No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The Persistent Effects of Concussion on Neuroelectric Indices of Attention
Abstract
Mild traumatic brain injuries (mTBIs) that result from participation in sports are a major public health issue affecting 1.6-3.8 million individuals annually. The injury has been postulated as transient and void of long-term consequences when rapidly diagnosed and properly managed. Emerging evidence, however, has suggested an increased risk for late life cognitive dysfunction in those with previous injuries. The purpose of this investigation was to evaluate young adults with and without a history of concussion using a standard clinical assessment and highly sensitive electrophysiological measures for persistent changes in cognitive functioning. Ninety participants (19.7 +/- 1.3 years; 44 without mTBI and 46 with previous mTBI) were evaluated using the ImPACT and event-related brain potentials (ERPs) that were recorded during a three-stimulus oddball task. Those with a history of concussion reported an average of 3.4 years post-injury. No significant differences were found between groups on the ImPACT. Significant decrements in the N2 and P3b amplitudes of the stimulus-locked ERP were noted for those with a history relative to those without a history of concussion. Although the previously concussed participants performed equal to those without injury on the clinical cognitive assessment, these findings support the notion that sport mTBI can no longer be thought of as a transient injury resulting in short-lived neurological impairment. It is not clear if these persistent deficits will manifest into clinical pathologies later in life.
... 19,20 Additionally, since the brain is still developing during high school, there is a greater concern for the effects concussions have on cognitive function throughout the recovery process. [21][22][23] Concussion management remains a subjective process with a clinical evaluation serving as the best diagnostic tool. Concussion sideline assessments are used largely as aides to measures cognitive deficits following injury. ...
... Research has shown the utility of ERPs following sport-related concussion and the ability for ERPs to identify continued concussion deficits. 22,23,[32][33][34][35] Specifically, research suggests decreased P3 and N2 amplitudes and longer P3 latencies following concussion, suggesting individuals have a harder time allocating attentional resources during tasks. 22,23,[32][33][34][35][36][37] Further, ERP use following concussion has identified working memory deficits. ...
... 22,23,[32][33][34][35] Specifically, research suggests decreased P3 and N2 amplitudes and longer P3 latencies following concussion, suggesting individuals have a harder time allocating attentional resources during tasks. 22,23,[32][33][34][35][36][37] Further, ERP use following concussion has identified working memory deficits. 37 These studies further support the use of ERP following concussion. ...
Context: 7 million athletes participate in high school sports annually. Approximately 1 million of these athletes participate in football, which is associated with repetitive head impacts. Concussion literature suggests sub-concussive impacts may lead to declines in brain function across a season of football. Furthermore, recent research suggests following clinical concussion recovery, metabolic and neurophysiological recovery may not be complete. Objective: The purpose of this study was to monitor head impacts and cognitive function during (72hour, asymptomatic) and after concussion and longer term over a full football season (pre-season, mid-season, post-season). Participants: 106 male adolescent (46 football-athletes, 42 controls for football-athletes, 9 concussed-athletes, 9 controls for concussed-athletes). Outcome measures: The Head Impact Telemetry System encoder was used to track the location and magnitude of head impacts during football participation. Psychophysiology was measured using Electroencephalography and was quantified using a 256 channel system to record brain activity during an auditory oddball task. All Participants completed Axon neurocognitive testing, clinical reaction time task (CRT), symptom inventory and two Health Related Quality of Life Surveys (Health Behavior Inventory, Satisfaction with Life) throughout the above testing time-points. Results: Football-athletes sustained a mean of 482 head impacts during all practices and games. Mixed measures ANOVA indicated a significant decrement on one BNA output score, Target amplitude, with lower post-season scores (p<0.05). No other BNA output scores, Axon, CRT, SWL, or HBI measurements showed significant deficits post-season (p>0.05). Furthermore, P3a amplitudes were significantly larger and N2 latency was longer during post-season testing. Mixed measured ANOVAs indicated no significant deficits in BNA output scores, Axon performance, CRT, and HRQOL, for concussed and matched controls across post-injury time points. Additionally, there was a significantly longer P3a latency post-season latencies across groups and smaller P3a amplitudes at post-season for concussed compared to controls (p<0.05). Conclusion: Overall, these findings suggest electrophysiology changes between pre and post-season testing among football athletes and control participants without concussion, with the majority demonstrating improved cognitive function. Therefore, no negative effects may be associated with repeated head impacts in one season of football. Furthermore, no cognitive deficits were present during asymptomatic testing following concussion.
... The N2b, which is generated from ACC (Crottaz-Herbette and Menon, 2006), is thought to primarily reflect higher-order "executive functions" requiring conscious attention (Patel and Azzam, 2005;Downes et al., 2017). N2b is believed to index cognitive processes including response selection and inhibition, stimulus-response conflict adaptation, emotional control, and stimulus discrimination (Courchesne et al., 1975;Czigler et al., 1996;Lange et al., 1998;Smid et al., 1999;Senkowski and Herrmann, 2002;Koivisto and Revonsuo, 2003;Wang et al., 2003;Czigler and Balázs, 2005;Knyazev et al., 2008;Broglio et al., 2009;Mäki-Marttunen et al., 2015). Several studies discussed in the present review utilized paradigms that elicit the N2b while referring to the component with the more general term known as N2. ...
... Observable symptoms of concussion, such as dizziness and increased sensitivity to light and sound, typically occur only for seven to 10 days postinjury, although ∼20-25% of patients experience symptoms beyond that period in what is termed post-concussion syndrome, or PCS (McCrory et al., 2017). Several studies have identified cognitive and executive functioning deficits, as well as psychiatric disorders such as post-traumatic stress disorder (PTSD) and depression, persisting years post-concussion (Broglio et al., 2009;Gosselin et al., 2012;Martini et al., 2017;Ruiter et al., 2019;Cunningham et al., 2020). However, many others have reported no significant changes in attention, executive functioning or information processing following symptom resolution as evaluated by neuropsychological testing (Potter et al., 2001(Potter et al., , 2002Segalowitz et al., 2001;Guskiewicz et al., 2002). ...
... Standard neuropsychological tests as well as computerized administration of cognitive tests including the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) are typically used to measure cognitive and emotional control among people with concussion, yet lack the sensitivity to measure the more subtle manifestations of cognition including executive functioning deficits after symptom resolution (Broglio et al., 2009;Ledwidge and Molfese, 2016;Hudac et al., 2018;Olson et al., 2018). Executive functioning skills, including time management, task switching, sustained attention and working memory, are vital for career and interpersonal success yet can be challenging to accurately measure (Elliott, 2003;Van Beek et al., 2015;Downes et al., 2017). ...
Objectives: The N2b is an event-related potential (ERP) component thought to index higher-order executive function. While the impact of concussion on executive functioning is frequently discussed in the literature, limited research has been done on the role of N2b in evaluating executive functioning in patients with concussion. The aims of this review are to consolidate an understanding of the cognitive functions reflected by the N2b and to account for discrepancies in literature findings regarding the N2b and concussion.
Methods: A scoping review was conducted on studies that used the N2b to measure cognitive functioning in healthy control populations, as well as in people with concussions.
Results: Sixty-six articles that met inclusion criteria demonstrated that the N2b effectively represents stimulus-response conflict management, response selection, and response inhibition. However, the 19 included articles investigating head injury (using terms such as concussion, mild head injury, and mild traumatic brain injury) found widely varied results: some studies found the amplitude of the N2b to be increased in the concussion group, while others found it to be decreased or unchanged.
Conclusion: Based on the available evidence, differences in the amplitude of the N2b have been linked to response selection, conflict, and inhibition deficits in concussion. However, due to large variations in methodology across studies, findings about the directionality of this effect remain inconclusive. The results of this review suggest that future research should be conducted with greater standardization and consistency.
... Attention is often diminished in the acute phase following concussion and attentional resources have been shown to be reduced months to years following concussion. 16,59,36,12,60 Finally, it is possible that these differences are the result of impaired learning. The healthy controls were able to adapt to the dual task by day 5, but the concussed individual were not. ...
... The decreased P3 was demonstrated in the absence of differences on the ImPACT. 59 These findings help to support the theory that previously concussed individuals have reduced attentional resources and may use greater cognitive resources to achieve equivalent performance and/or experience accelerated aging. ...
... 87 Over the course of a single season, college players receive an average 800-1000 impacts, 45,48,36 and while the frequency of NFL player impact exposure is unknown, it is likely even higher. Considering the growing link between neural damage and concussive/subconcussive impacts alone, 13,15,38,42,43,46,47,59,60,63 increasing the number of seasons an athlete participates in will yield a large increase in the total number of impacts an individual experiences in their lifetime. This would indicate that the longer an individual's career, the more likely they are to receive impacts that will result in long-term and permanent deficits. ...
Football is a high frequency and magnitude contact sport. Contact sports carry a higher rate of impacts to the head which are inherently associated with an increased risk of developing concussive injuries. Growing evidence indicates that subconcussive and concussive injuries can result in physiological changes which may lead to the development of cognitive, behavioral, and physical deficits. There is also evidence linking subconcussive and concussive injuries to neurodegenerative diseases like Chronic Traumatic Encephalopathy, Alzheimer’s Disease, and Amyotrophic Lateral Sclerosis. Over the course of an athlete's career, concussive and subconcussive damage may accumulate and can result in permanent and devastating long-term dysfunction. Certain positions experience different types and frequencies of impacts, therefore, concussive and subconcussive-induced deficits may vary by position. This study compared retired NFL players(n=24), similarly aged non-contact controls(n=15) and position matched collegiate players(n=24) using the VR HeadRehab 3 system in order to identify any potential long-term deficits. Players were tested on measures of balance, reaction time and spatial memory. Further analysis sought to identify any relationships or risk factors for the onset of these deficits. NFL players performed significantly worse than both control groups on all VR measures. This poorer performance was associated with player career length and position. Career length was significantly associated with longer reaction time. Players in positions that were more likely to receive concussive-type(less frequent but higher magnitude) impacts had poorer spatial memory, while players in positions that experience greater subconcussive(more frequent but lower magnitude) impacts were more likely to have poorer balance. Limited evidence suggests poorer VR performance at the collegiate level.
... Generally, ERP research on concussion employs an active "oddball" (Donchin and Ritter, 1978) protocol (e.g., Rugg et al., 1988;Gosselin et al., 2006;Ruiter et al., 2019). This protocol has been utilized to examine the effects of concussion on two ERP components in particular: the P300 and the N2b (e.g., Gaetz et al., 2000;Broglio et al., 2009;De Beaumont et al., 2009;Broglio et al., 2011;Baillargeon et al., 2012;Ruiter et al., 2019). The N2b is generated from the anterior cingulate cortex (ACC) (Huster et al., 2010) -an area associated with executive function and other executive-related cognitive processes (Carter et al., 1999;MacDonald et al., 2000). ...
... The N2b is generated from the anterior cingulate cortex (ACC) (Huster et al., 2010) -an area associated with executive function and other executive-related cognitive processes (Carter et al., 1999;MacDonald et al., 2000). The N2b is a negative-deflecting neurophysiological response peaking~200 ms post stimulus onset and characterized by a fronto-central scalp distribution linked to response inhibition, response conflict monitoring, and executive control (Boksem et al., 2005;Folstein & Van Petton., 2008;Broglio et al., 2009). Research has demonstrated attenuated N2b responses in adult concussed populations relative to healthy controls , reflecting cognitive dysfunction in both response inhibition and executive control. ...
... The P3b reduction found in the present study is consistent with previous concussion literature (Lavoie et al., 2004;Theriault et al., 2009;Baillargeon et al., 2012) and provides further evidence that specific neurophysiological markers of attention and working memory function can track commonly reported cognitive symptoms of concussion (Gronwall, 1989;Broglio et al., 2009;Theriault et al., 2009;Ozen et al., 2013). ...
Objective
The present study sought to determine: 1) whether concussed adolescents exhibited deficits in neurocognitive functioning as reflected by neurophysiological alterations; 2) if neurophysiological alterations could be linked to supplementary data such as the number of previous concussions and days since injury; and 3) if deficits in psychological health and behavioural tests increased during diagnosis duration.
Methods
Twenty-six concussed adolescents were compared to twenty-eight healthy controls with no prior concussions. Self-report inventories evaluated depressive and concussive symptomatology, while behavioral tests evaluated cognitive ability qualitatively. To assess neurophysiological markers of cognitive function, two separate auditory oddball tasks were employed: 1) an active oddball task measuring executive control and attention as reflected by the N2b and P300, respectively; and 2) a passive oddball task assessing the early, automatic pre-conscious awareness processes as reflected by the MMN.
Results
Concussed adolescents displayed delayed N2b and attenuated P300 responses relative to controls; showed elevated levels of depressive and concussive symptomatology; scored average-to- low-average in behavioral tests; and exhibited N2b response latencies that correlated with number of days since injury.
Conclusion
These findings demonstrate that concussed adolescents exhibit clear deficiencies in neurocognitive function, and that N2b response latency may be a marker of concussion recovery.
... Refinements in assessment tools have predominantly targeted the disentanglement of concussion's constellation of symptoms. Several methodologies have shown promise, such as eye movements (Heitger et al., 2009;Johnson et al., 2012), balance assessments , functional brain imaging (McAllister et al., 2001) and electrophysiology (Broglio et al., 2009;De Beaumont et al., 2009;Ruiter et al., 2019). In the last category, event-related potentials (ERPs) as recorded with electroencephalography (EEG) were shown to be altered following concussion (Gaetz et al., 2000;Gosselin et al., 2006;De Beaumont et al., 2007;Broglio et al., 2011). ...
... The extent of ERP alterations after concussion was demonstrated to correlate with number of hits Graphical Abstract to the head, severity of injury and time elapsed since injury (De Beaumont et al., 2007;Broglio et al., 2011). Most prominent in concussion research, the N2b-indexing executive control and response inhibition-and the P300-associated with attention, orientation, and memory-have been shown to be particularly affected after insult, either in response latency, amplitude, or both (Gosselin et al., 2006;De Beaumont et al., 2007Broglio et al., 2009;Ruiter et al., 2019). The association between these ERPs and specific cognitive processes has provided a valuable tool to pinpoint the functional and cognitive effects of concussion that have been reported to linger after symptom resolution (Gosselin et al., 2006;De Beaumont et al., 2007;Baillargeon et al., 2012). ...
... Most findings on the neurophysiological effects of concussion to date describe an attenuation or delaying of brain responses (Gosselin et al., 2006;De Beaumont et al., 2007Broglio et al., 2009;Ruiter et al., 2019). Contrary to these findings, several studies have reported hyperactivation post-injury during mentally taxing tasks (McAllister et al., 2001). ...
The current literature presents a discordant view of mild traumatic brain injury and its effects on the human brain. This dissonance has often been attributed to heterogeneities in study populations, etiology, acuteness, experimental paradigms, and/or testing modalities. To investigate the progression of mild traumatic brain injury in the human brain, the present study employed data from 93 subjects (48 healthy controls) representing both acute and chronic stages of mild traumatic brain injury. The effects of concussion across different stages of injury were measured using two metrics of functional connectivity in segments of electroencephalography (EEG) time-locked to an active oddball task. Coherence and weighted phase-lag index were calculated separately for individual frequency bands (delta, theta, alpha, and beta) to measure the FC between six electrode clusters distributed from frontal to parietal regions across both hemispheres. Results show an increase in functional connectivity in the acute stage after mild traumatic brain injury, contrasted with significantly reduced functional connectivity in chronic stages of injury. This finding indicates a non-linear time-dependent effect of injury. In order to understand this pattern of changing functional connectivity in relation to prior evidence, we propose a new model of the time-course of the effects of mild traumatic brain injury on the brain that brings together research from multiple neuroimaging modalities and unifies the various lines of evidence that at first appear to be in conflict.
... The N2b is an ERP often linked to executive function manifesting as a fronto-central negative deflection 200 ms after stimulus onset 16 . Similar to the P300, the N2b was affected after sustaining hits to the head 7,10,15,17,18 . Research has demonstrated the versatility and sensitivity of both the P300 and N2b to concussion; however, a transition from controlled, group-level findings to individual assessment is required before clinical adoption is made feasible. ...
... Combining all these tools was reported to exceed 90% sensitivity, although it is critical to be mindful that with these increments in sensitivity, specificity of these methods deteriorates and, by definition, reduces accuracy. Overall, we argue that the implementation of a single-subject EEG/ERP evaluation for acute/post-acute concussion is feasible provided group-level studies in the literature 17,35 and extended to single-subjects by the methodology presented here. Clinical applicability beyond the acute stage, however, requires further investigations that would augment the data used for training as discussed above. ...
... This is compatible with a hypothesis that alterations in earlier responses (in the mismatch negativity 10 or the N1/P2 complex 24 ) may correspond to irreversible effects of concussion and are strictly prominent in chronic cases. Further, tracing the model's results provides additional, empirical and data-driven, support of mTBI's impact on facets of cognitive function linked to the P300 and N2b such as attention and executive function 10,17,41 . ...
Concussion has been shown to leave the afflicted with significant cognitive and neurobehavioural deficits. The persistence of these deficits and their link to neurophysiological indices of cognition, as measured by event-related potentials (ERP) using electroencephalography (EEG), remains restricted to population level analyses that limit their utility in the clinical setting. In the present paper, a convolutional neural network is extended to capitalize on characteristics specific to EEG/ERP data in order to assess for post-concussive effects. An aggregated measure of single-trial performance was able to classify accurately (85%) between 26 acutely to post-acutely concussed participants and 28 healthy controls in a stratified 10-fold cross-validation design. Additionally, the model was evaluated in a longitudinal subsample of the concussed group to indicate a dissociation between the progression of EEG/ERP and that of self-reported inventories. Concordant with a number of previous studies, symptomatology was found to be uncorrelated to EEG/ERP results as assessed with the proposed models. Our results form a first-step towards the clinical integration of neurophysiological results in concussion management and motivate a multi-site validation study for a concussion assessment tool in acute and post-acute cases.
... These findings persisted long after behaviourally-identified symptoms had resolved, further demonstrating the inadequacy of assessing concussion using behavioural measures alone. Various ERPs were found to be affected by mTBI [5], [6], [14]. In this study we investigated how reliably the P300, a heavily studied ERP, and other precursor ERPs can be used as concussion identification markers for individuals who sustained their last injury years prior. ...
... This ERP has been shown to be attenuated and delayed after mTBI, with the effect persisting after symptom resolution [16]. The P300 can be subclassified into the P3a and the P3b, which were shown to be both altered after concussion [5], [6], [14]. The P3a is a fronto-central component associated with attention orienting and is followed by the P3b, a centro-parietal component often linked to processes related to memory and attention allocation [15]. ...
... Interestingly, our results indicate that the responses to the standard condition, particularly in the N100-P200 time span, carried substantial discriminative information, making up 12 of the 25 top features. These responses are commonly discarded or used strictly to calculate ERP difference waves (i.e., by subtracting the standard condition from the averaged ERP generated by a deviant condition; see [5], [6]). ...
There has been increased effort to understand the neurophysiological effects of concussion aimed to move diagnosis and identification beyond current subjective behavioural assessments that suffer from poor sensitivity. Recent evidence suggests that event-related potentials (ERPs) measured with electroencephalography (EEG) are persistent neurophysiological markers of past concussions. However, as such evidence is limited to group-level analyses, the extent to which they enable concussion detection at the individual-level is unclear. One promising avenue of research is the use of machine learning to create quantitative predictive models that can detect prior concussions in individuals. In this study we translate the recent group-level findings from ERP studies of concussed individuals into a machine learning framework for performing single-subject prediction of past concussion. We found that a combination of statistics of single-subject ERPs and wavelet features yielded a classification accuracy of 81% with a sensitivity of 82% and a specificity of 80%, improving on current practice. Notably, the model was able to detect concussion effects in individuals who sustained their last injury as much as 30 years earlier. However, failure to detect past concussions in a subset of individuals suggests that the clear effects found in group-level analyses may not provide us with a full picture of the neurophysiological effects of concussion.
... Preliminary evidence has shown that concussion-related deficits might be due to ongoing cognitive problems. Outside of sport performance, researchers 16,[26][27][28] have demonstrated ongoing cognitive deficits at the time when an athlete would RTP. For example, in a sample of collegiate American football athletes, McCrea et al 21 reported that up to 16% of asymptomatic athletes demonstrated abnormal neurocognitive performance. ...
... 21 Cremona-Meteyard and Geffen 27 described greater visual-spatial reaction time among rugby players up to a year postinjury, indicating impaired visual attention. Using electroencephalography, O n l i n e F i r s t investigators have detected attention-related deficits up to 30 years postinjury, 16,26 along with slower movement, 26 among an otherwise healthy sample. Collectively, the evidence has indicated that clinical resolution of symptoms may not represent true brain recovery postinjury. ...
... Our work was not designed to elucidate the biological underpinnings of performance decline, but persistent deficits in the domains of reaction time, 27 gait, 9 and decision making 16 have been reported postconcussion. Both the concussion and lower body injury groups experienced initial decreases in performance, yet the mechanisms for these declines might have been different. ...
Context:
Concussions elicit changes in brain function that may extend well beyond clinical symptom recovery. Whether these changes produce meaningful deficits outside the laboratory environment is unclear. The results of player performance postconcussion within professional sports have been mixed.
Objective:
To determine whether National Hockey League (NHL) players with concussions performed worse after returning to sport than players with lower body injuries or uninjured players.
Design:
Cohort study.
Setting:
Publically available Web sites that compiled injury and player statistics of NHL players.
Patients or other participants:
Male NHL players who missed games due to a concussion (n = 22), lower body injury (n = 21), or noninjury (ie, personal reason or season break; n = 13) during the 2013-2014 and 2014-2015 regular seasons. Data on concussed athletes were used to identify similar players with lower body injury and noninjury based on (1) position, (2) time loss, (3) time on the ice, and (4) team.
Main outcome measure(s):
The primary performance metric was a modified plus-minus statistic calculated by weighting the players' plus-minus metric by their team's simple rating system to account for varying team performances. Linear mixed models assessed the relationship between injury type (concussion, lower body, or noninjury) and performance (plus-minus score).
Results:
We observed a quadratic effect for a time × group interaction ( \chi _2^2 = 8.85, P = .01). This interaction revealed that the concussion and lower body injury groups had similar patterns of an initial decrease (ie, 2 weeks after return to play), followed by an increase in performance compared with the uninjured group in weeks 5 and 6. Meanwhile, the uninjured group had an initial increase in performance. We observed no group × linear time interaction (P = .47) or overall group effect (P = .57).
Conclusions:
The NHL players in the concussion and lower body injury groups displayed similar performance impairments. Both injured cohorts experienced an initial decrease in performance at weeks 1 to 2 after return to play, followed by improved performance at weeks 5 to 6 after return to play, suggesting that the performance implications of concussion may be short lived.
... In addition to measuring cognition psychophysically, researchers have utilized electrophysiological measurements of visuospatial attention in individuals who have sustained a mTBI. Briefly, electroencephalography (EEG) measures the electrical activity of an individual's brain while performing an experimental task (Broglio, Pontifex, O'Connor, & Hillman, 2009). One measurement obtained from EEG is event-related brain potentials (ERPs), which record electrical neural activity either in response to, or as a result of, a stimulus (Broglio et al., 2009). ...
... Briefly, electroencephalography (EEG) measures the electrical activity of an individual's brain while performing an experimental task (Broglio, Pontifex, O'Connor, & Hillman, 2009). One measurement obtained from EEG is event-related brain potentials (ERPs), which record electrical neural activity either in response to, or as a result of, a stimulus (Broglio et al., 2009). One ERP of interest in the mTBI literature has been the P300, or P3, wave (Broglio et al., 2009;De Beaumont et al., 2009). ...
... One measurement obtained from EEG is event-related brain potentials (ERPs), which record electrical neural activity either in response to, or as a result of, a stimulus (Broglio et al., 2009). One ERP of interest in the mTBI literature has been the P300, or P3, wave (Broglio et al., 2009;De Beaumont et al., 2009). This wave can be divided into two subcomponents, the P3a and P3b waves; the former is associated with stimulus Note. ...
Athletes must be able to successfully navigate the soccer pitch or hockey rink to win the game, requiring maximal cognitive resources to successfully compete. Concussions potentially deplete these resources, and the long-term impact of concussions on an individual’s goal-directed visually guided behavior continues to elude the scientific community. While the acute effects on cognition and the motor system have been elucidated elsewhere, long-term effects on performance have been less clear. Additionally, most investigations into long-term postinjury motor behaviors have focused on balance and gait, with little focus on functional upper extremity movements. These arm movements require both cognitive and motor functions to successfully complete the task, such as visually guided reaching, and have received little attention. This review examines the current state of the literature to date on the long-term effects of concussions on cognitive and motor deficits affecting visuomotor behavior.
... EEGs measure the sum of all the Event-related brain potentials (ERPs) occurring at the time of measurement. ERPs represent voltage changes in neurons in response to a specific stimulus (23). ERPs are useful in providing insight to underlying cognitive function (23), and tracking changes in electrical function after concussion (24). ...
... ERPs represent voltage changes in neurons in response to a specific stimulus (23). ERPs are useful in providing insight to underlying cognitive function (23), and tracking changes in electrical function after concussion (24). However, these deficits are not always accompanied with presentation of symptoms (25, 26). ...
... On average, all groups showed increased in P3a amplitude. This contradicts findings of no change in P3a amplitude following concussion in other studies (23). These changes eluded to an increase in attention needed to focus on the relevant task. ...
Abstract
Contact sport teams require their athletes to undergo baseline concussion testing for comparison to their post-concussion results. The standard test during this study was the Sport Concussion Assessment Tool-3rd edition (SCAT-3). Clinically used for return to play procedure, most athletes return to baseline scores 8-10 days’ post-concussion. Electroencephalography (EEG) is a non-invasive means of measuring the electro-physiological function of the brain. EEGs are the summative measure of Event-Related Potentials (ERPs) which are measures of brain activity after a specific event. P300 is an example of an ERP that is commonly used as a neurocognitive marker in concussion research. P300 can be further broken down into P3a and P3b, which relate to attention and decision making respectively. Using this technique, lasting functional deficits, beyond those that are highlighted on the SCAT-3 scores, have been noted. This study aims to evaluate the effect subconcussive impacts (SCI) have on SCAT-3 and electrophysiology from one season to the next in Canadian University football players over two seasons. Participants underwent standard SCAT-3 and EEG baseline testing at the beginning of two subsequent seasons. The EEG tests consist of two 5-minute baseline periods with eyes open and closed, followed by a 10-minute session collecting event-related potentials using a three-stimulus Oddball paradigm. Players mean scores showed increases in both number of symptoms (1±4.08) and symptom severity (1.9±6.6). Mean P3a and P3b latencies increased. Additionally, mean amplitudes decreased for both P3a and P3b. University Football players show physiological defects from accumulated SCI during a season. These deficits may accumulate each successive season without resolution. Due to their slow onset, evaluations of these changes are difficult identity. EEG measurements are sensitive to small changes in function and serve as an ideal tool to measure these changes. The SCAT-3 is less sensitive to these minor changes but still has value since it can be used acutely in sideline assessment of concussion.
... The majority of this evidence relates to an ERP known as the P300 (P300m in MEG), a cognitive response that reflects stimulus-driven activation of attention mechanisms and subsequent contextual updating in working memory (19). A variety of paradigms, both auditory and visual in nature, have repeatedly demonstrated reduced P300 amplitudes in individuals with concussion compared to healthy controls, which are suggestive of reduced attentional capacity (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Some studies have reported amplitude reduction months to years following injury, even in the absence of clinical symptoms, suggesting the presence of persistent neurophysiological changes (20,23,25,27,31). ...
... The present study also demonstrated reduction of the P300m with concussion, which aligns with a rich literature implicating this evoked response as an index of concussion (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). This research has been performed using a wide range of experimental paradigms and suggests reduced attentional capacity following injury. ...
... The majority of studies used participants whose concussions had occurred months or years prior (20)(21)(22)(23)(24)(25)(26)(27)(29)(30)(31). The present results therefore corroborate the findings of Pratap-Chand and colleagues, who studied patients approximately 4 days from injury, to confirm that P300 is reduced very early following concussion (28). ...
Primary objective: To examine the effect of concussion on indices of attention using magnetoencephalography.
Methods and procedures: Thirteen patients were recruited from the emergency department and scanned within 3–6 days of injury. Five returned for follow-up scans one and three months post-injury. Thirteen healthy controls also completed testing. During MEG acquisition, participants performed the Attention Network Test (ANT). Cognitive evoked responses to this task include a cue-evoked P300m, a contingent magnetic variation (CMV) and a target-evoked P300m. The Rivermead Postconcussion Symptom Questionnaire and Sport Concussion Assessment Tool (SCAT3) were administered in all sessions.
Results: Patients suffering from concussion had slower response times and benefitted more from spatial cues than did controls. Global activation for all three evoked responses was lower for patients than controls. In a small sample of patients who returned for follow-up, the CMV and target P300m improved with recovery.
Conclusions: MEG-evoked responses to the ANT reveal neurophysiological evidence of attentional dysfunction within days of injury. A pattern of improvement was also observed over the course of three months for the P300m, while behavioural performance did not change significantly. Further development of this method may yield a useful adjunct to neurological examination for concussion diagnosis and monitoring.
... Previous evidence indicates that adults with mild traumatic brain injury exhibited a reduced NoGo N2 responses when primed by a negative affective symbol (e.g., spider versus flower, 33). The N2 is likely a relevant and important target, as evidenced by reduced N2 amplitudes for young adults with a history of concussion during other cognitive tasks (34,35). However, despite the need to examine the instantaneous dynamic changes (36), no work has utilized a trial-level analytic approach to understand how increasing frustration influences cognition on a moment-to-moment basis during this task. ...
... injury (34,35,38). In contrast, the frustration induction was more effective in athletes that endorsed a history of anxiety, depression, and/or ADHD. ...
Introduction
Concussive events and other brain injuries are known to reduce cognitive inhibition, a key aspect of cognition that supports ones' behaviors and impacts regulation of mood or affect. Our primary objective is to investigate how induction of negative affect (such as frustration) impacts cognitive inhibition and the dynamic process by which youth athletes modulate responses. Secondary objective is to address the lack of Black representation in the scientific literature that promotes brain health and investigates pediatric sports-related brain injury. In particular, neuroscience studies predominantly include White participants despite broad racial representation in sport, in part due to technological hurdles and other obstacles that challenge research access for Black participants.
Methods
Using electroencephalography (EEG), we evaluate the dynamic brain processes associated with cognitive inhibition in the context of frustration induction in adolescent athletes during pre-season conditioning (i.e., prior to contact; N = 23) and a subset during post-season ( n = 17).
Results
The N2 component was sensitive to frustration induction (decreased N2 amplitude, slower N2 latency), although effects were less robust at postseason. Trial-by-trial changes indicated a steady decrease of the N2 amplitude during the frustration block during the preseason visit, suggesting that affective interference had a dynamic effect on cognitive inhibition. Lastly, exploratory analyses provide preliminary evidence that frustration induction was less effective for athletes with a previous history of concussion or migraines (trending result) yet more effective for athletes endorsing a history with mental health disorders.
Discussion
We emphasize the urgent need to improve representation in cognitive neuroscience, particularly as it pertains to brain health. Importantly, we provide detailed guides to our methodological framework and practical suggestions to improve representative participation in studies utilizing high-density mobile EEG.
... Conversely, research investigating between-group differences in cognitive performance in the chronic stage of mTBI has revealed conflicting findings. While some evidence suggests reduced cognitive performance in the above-mentioned domains persists in the months to years following injury 11,12 , other studies have observed no long-term deficits in mTBI populations 13,14 . Review papers exploring cognitive outcome in the chronic stage of mTBI have also revealed mixed findings. ...
... These findings align with numerous past studies demonstrating that, at a group level, mTBI is not associated with long-term cognitive impairment 13,14,28,29 . While recent research by Arciniega et al. 34 revealed evidence for prolonged visual working memory deficits in undergraduate students with a history of mTBI, we failed to replicate these findings in a Bayesian, preregistered study with a comparable sample size. ...
The long-term cognitive consequences of mild traumatic brain injury (mTBI) are poorly understood. Studies investigating cognitive performance in the chronic stage of injury in both hospital-based and population-based samples have revealed inconsistent findings. Importantly, population-based mTBI samples remain under-studied in the literature. This study investigated cognitive performance among individuals with a history of self-reported mTBI using a battery of cognitively demanding behavioural tasks. Importantly, more than half of the mTBI participants had experienced multiple mild head injuries. Compared to control participants (n = 49), participants with a history of mTBI (n = 30) did not demonstrate deficits in working memory, multitasking ability, cognitive flexibility, visuospatial ability, response inhibition, information processing speed or social cognition. There was moderate evidence that the mTBI group performed better than control participants on the visual working memory measure. Overall, these findings suggest that even multiple instances of mTBI do not necessarily lead to long-term cognitive impairment at the group level. Thus, we provide important evidence of the impact of chronic mTBI across a number of cognitive processes in a population-based sample. Further studies are necessary to determine the impact that individual differences in injury-related variables have on cognitive performance in the chronic stage of injury.
... In two successive studies Gosselin et al. examined the root cause of persistant symptoms post-TBI [113,114]. Using functional magnetic resonance imaging (fMRI), blood-oxygen-level-dependent (BOLD) signal changes and ERPs they compared 14 mTBI subjects with 23 controls [113]. fMRI findings were positively correlated while BOLD signal changes and N350 amplitude were inversely correlated with symptom severity. ...
... Amplitude and latency of frontal (N200 and N350) and parietal (P200 and P300) were studied. Groups did not differ by ERP latency [114]; however, mTBI had significantly smaller N350 and P300 amplitudes, slower reaction times, worse accuracy and a lower percentage of correct answers than the control group (p<0.05). They reported that given current follow-up testing for mTBI clinicians may fail to detect and therefore treat consequences of mTBI especially if sub-clinical cerebral/ cortical dysfunction existed. ...
... Noteworthy were the findings of Hung et al (2017) and van Heugten et al (2006), who reported long-term decreases in attentional abilities after moderate to severe TBI. Broglio et al (2009) used EEG to measure cortical responses to a visual oddball task in a mild TBI population sample with an average of 3.4 (SD = 3.0) years post injury. In this study, individuals who had experienced a TBI showed a significant reduction in amplitude of the N2 and P3b event-related potential components to target stimuli, suggesting that deficits in stimulus categorization processes and attention orienting after a mild TBI do not resolve quickly during the postacute stage of TBI recovery. ...
... Twenty-four studies (46%) measured processing speed, with all but six reporting a reduction in processing speed in individuals with TBI compared with HC (Alexander et al, 2015;Broglio et al, 2009;Ettenhofer and Abeles, 2009;MacDonald, 2016;Ozen et al, 2010;Robinson-Boone, 1999). The six studies not reporting a reduction in performance in individuals with TBI included only individuals with mild and/or mild and moderate TBI severity. ...
Given the importance of the period of life from 10 to 30 years in terms of cognitive development and education, combined with the high incidence of traumatic brain injury (TBI) during this period, and limited consensus as to the pattern and degree of cognitive impairment post TBI during this period, we conducted a systematic review to investigate cognitive performance across a range of domains among individuals between the ages of 10 and 30 years who had sustained a TBI. We searched five databases and identified 799 unique records; 52 met our inclusion criteria. These studies reported cognitive function for intelligence, attention, memory, processing speed, and executive function. The majority of the studies reported significant effects, suggesting that TBI is associated with cognitive impairments in these domains. Nine of the studies used physiological tests (EEG and fMRI), the outcomes of which supported behaviorally demonstrated cognitive deficits. In the studies we reviewed, individuals aged 10–30 years who had experienced a TBI performed worse than healthy controls on cognitive function measures—specifically for attention, memory, processing speed, and executive function. In the studies that subjected the individuals with TBI to EEG and fMRI, atypical activation in associated brain regions was demonstrated while the individuals were undergoing cognitive tasks. However, caution should be taken when interpreting the overall results due to the high risk of bias across the majority of the studies. The broader implications of reduced cognitive performance after TBI across this age range are yet to be fully understood.
... There are an estimated 1.6-3.8 million concussions that occur from sports and recreational activity in the United States annually 1 . Board Certified Athletic Trainers (ATC) provide a critical safety net due to limited knowledge and misconceptions of concussions held by some coaches and athletes. ...
... Concussions account for 5-9% of all sports injuries, which often translate into visits to the emergency room 3 . For most athletes (80-90%) concussions resolve in 7-10 days, however in some cases, symptoms can persist for months or even years 1 . The dangers of these injuries include prolonged post-concussive symptoms, increased risk of subsequent concussions, seizures, mental health issues including depression, and in rare cases, death. ...
Annually, 1.6-3.8 million concussions occur from sports in the United States, which account for 5-9% of all sports injuries. The dangers of concussions include prolonged post-concussive symptoms, increased risk of subsequent concussions, seizures, mental health issues, and in cases of second-impact syndrome (SIS), possible death. Certified Athletic Trainers (ATC) continue to serve an important role in providing assessment and treatments for athletes with sports-related injuries. They provide a critical safety net due to limited knowledge and misconceptions of concussion held by some youth sports coaches and athletes. However, availability of services from ATCs in rural areas is a challenge. In order to help extend coverage to more rural student athletes, we propose designing a telemedicine app following the mHealth development roadmap from the Center for eHealth Research (CeHRes). In this paper we will document contextual inquiry, user requirements capture, design phases, and app evaluation from the targeted user base.
... Ces anomalies neuroélectriques pourraient être permanentes. En effet, Broglio et al. ont constaté 3 ans après une commotion que certains dérèglements persistaient toujours (Broglio, Pontifex, O'Connor, & Hillman, 2009). Pour arriver à cette observation, ils ont évalué 90 participants (44 sans TCCL et 46 avec TCCL) à l'aide de l'ImPACT et ont aussi évalué les potentiels cérébraux évoqués par une tâche. ...
Objectif: Rechercher systématiquement et regrouper tous les articles publiés depuis la dernière recherche systématique sur le sujet, mais avec des critères d’inclusion précis pour faciliter les comparaisons et offrir une vision explicite des méthodologies employées et des résultats. Ceci permettra une présentation globale du comportement de la variabilité du rythme cardiaque au repos et à l’effort suite à une commotion cérébrale chez des adultes. Méthodologie: Une recherche systématique a été conduite en utilisant la méthode du PRISMA en décembre 2019 au travers des bases de données PubMed, Scopus et SPORTDiscus. Une recherche manuelle a été conduite au travers des références de tous les articles inclus. La fiabilité de la recherche systématique a été assurée par un deuxième auteur qui a entièrement répété le processus de sélection d’articles. Résultats: 15 articles ont été sélectionnés suite à la recherche systématique. Les résultats de ces études démontrent une altération de la variabilité du rythme cardiaque à l’effort suite à une commotion cérébrale, des études très hétérogènes avec un manque de contrôle des facteurs confondants et, seulement environ 50% des résultats démontraient une différence entre le groupe contrôle et le groupe avec commotion. Conclusion: Les recherches futures devraient tenter de standardiser les méthodes d’acquisition de VRC en contrôlant davantage les facteurs confondants pour faciliter les comparaisons futures et, éventuellement permettre le développement d’une méta-analyse.
... However, it is important to note that a growing body of literature suggests that long-term alterations may be observed using experimental cognitive paradigms several months to years after a concussion. Those alterations seem to be specific to the aspects of EF, such as cognitive flexibility, working memory, and inhibition and interference control (22,26,27,32,33,44,51,52,54,64,(68)(69)(70)(71)(72)(73)(74)(75)(76). Together with previous studies, the current findings reinforce the need for the development and validation of more sophisticated tests of complex cognitive processes to measure deficits that persist after a concussion. ...
This meta-analysis aimed to investigate the long-term (3+ months) consequences of concussion across cognitive domains (processing speed, memory, attention, and executive functions) and subdomains in young adult athletes (university, professional, or recreational). Six databases (EMBASE, PubMed, PsycINFO, SPORTDiscus, Web of Science, and Cochrane List of Registered Trials) were searched for studies that compared cognitive performance between athletes with a history of concussion (HOC) and control athletes who never sustained a brain injury. Thus, the analyses were restricted to the studies investigating sports concussions. Nineteen studies, including 20 independent experiments with 1514 participants (521 HOC athletes, 1184 controls), were identified. Athletes from the HOC group sustained an average of 2.40 ± 0.99 concussions, with an average of 29.88 ± 19.26 months after injury. Importantly, all HOC athletes were tested at least 3 months after their most recent concussion. The results indicated significant medium-to-large group differences (Hedges’ g = 0.55–1.03; P values < 0.0001) for executive functions subdomains on both standardized clinical tests and screening tools. Specifically, HOC athletes had lower cognitive performance relative to controls in strategy generation/regulation, verbal set-shifting and interference management on standardized clinical tests (Regensburger verbal fluency S words and G/R words), and response inhibition (ImPACT Impulse Control composite) and prospective working memory (Cogstate two-back task) on screening tools. Encoding phase of visual memory (Brief Visuospatial Memory Test) on standardized clinical tests approached significance (Hedges’ g = 0.40; P values = 0.08). The current findings provide a preliminary guideline to clinicians for the assessment of cognition in HOC athletes and inform future guidelines on common data elements of sport-related concussions.
... Per previously published research (Guskiewicz et al., 2007;Mainwaring, Hutchison, Comper, Richards, & Trenerry, 2012;Moore et al., 2015a), we employed the Beck Depression Inventory-II (BDI-II) and the Profile of Mood States (POMS) to assess psycho-affective states, and a modified Cogstate test battery to assess both lower-and upper-level cognitive functions (Sicard, Moore, & Ellemberg, 2018, 2019. Similar to prior concussion research (Baillargeon et al., 2012;Broglio et al., 2009;Moore et al., 2014), we sought to explore neurophysiological alterations associated with concussion by examining ERPs during a three-stimulus oddball task. Specifically, we sought to evaluate the ERP indices of lower-level attentional orienting (P3a; Polich, 2007), upper-level attentional resource allocation (P3b; Polich, 2007) during stimulus engagement, action monitoring (ERN; Gehring & Fencsik, 2001), and error awareness (Pe; Gehring & Fencsik, 2001) during response evaluation. ...
Objective
This study sought to cross-sectionally evaluate the relation between learning disorders (LD) and long-term concussion outcomes.
Method
Seventy-three asymptomatic male university athletes (23 history of concussion with LD; 24 history of concussion no LD; 26 controls) completed the Beck Depression Inventory-2 (BDI-II), the Profile of Mood States (POMS), the Cogstate battery, and an Oddball task during which event-related brain potentials were recorded.
Results
Concussed athletes with LD exhibited greater depressive symptoms (BDI-II), greater total mood disturbance (POMS) and decreased accuracy on the One-Card Learning and the N-back task (Cogstate), decreased accuracy on the Oddball task, and reduced ERN amplitude relative to both the concussed athletes without a LD and the controls. Concussed athletes with LD also exhibited prolonged P3 latency relative to controls. Irrespective of LD, concussed athletes exhibited increased anger-hostility and decreased Pe amplitudes relative to controls. No differences were observed in P3a amplitude or latency.
Conclusion
Having LD may be a significant factor moderating the neurophysiological, cognitive and psycho-affective outcomes of concussion, and may explain a significant portion of the persistent deficits observed by researchers and clinicians.
... They also noted that there is scant information regarding effects of concussion on an athlete when gender, type of sport, player position, concussion history and age at injury are considered -although paediatric injuries seem to have longest duration of effect. Evaluation of cognitive ability after concussion found no evidence of cognitive decline associated with concussion history -although this may reflect the lack of sensitivity of particular tests used to capture subtle long-term deficits [66,67]. Similarly, Hart et al., [68] found no correlation between concussion history, duration of play and cognitive performance in retired athletes. ...
Brain training apps are becoming increasingly popular for at home use and as an adjunct to more traditional therapies. There is uncertainty about whether the effects of brain training transfer to real-world cognition, or performance on other cognitive assessment tests, or is specific only to the brain training app. Executive functions (EF's) are higher-order cognitive processes important for activities of everyday living and autonomous goal-directed behaviour [1]. EF's are associated with frontal brain networks that are susceptible to injury after head trauma and concussion so it is important to know whether these functions can be trained after a short training period (transfer effects beyond gains on app play), to general cognitive ability but findings so far have been mixed. The present study investigated efficacy of brief computerised brain training to in producing far-transfer effects to performance on standardised clinical tests of cognition in young rugby players with mixed concussion history, over a 4-week period. Athletes cognitive ability was assessed at baseline and after the training period on standardised tests to establish whether there were transfer effects. The putative relationship between concussion frequency and severity on baseline cognitive performance was also investigated. Results showed effective transfer effects from initial training to selective visuospatial executive functions. There was also a decline over the training period in non-verbal strategy initiation, although ability remained at average levels. Players showed no cognitive deficits at baseline, but correlational analyses and MR results indicated that concussion frequency, not severity, was a significant predictor of some visuospatial executive function scores at baseline. These preliminary findings hold promise for full scale studies investigating efficacy of brief brain training and association between sport-related concussion and cognition.
... Despite reporting being asymptomatic, athletes in the concussion group exhibited a lower cognitive performance, as evidenced by low ACC, higher inverse efficiency, and higher global and working memory costs on the switch task relative to the control group. These results are in line with a growing body of literature suggesting significant group differences that persist beyond clinical recovery (23)(24)(25)(26)(27)(28)(29)(30), where clinical recovery is defined functionally as a return to normal activities, including school and sports, after injury (31). In the current study, a subgroup of athletes who were cleared to RTP after their concussion exhibited diminished performance in multiple aspects of executive functions relative to teammate controls, suggesting that although clinical recovery was achieved, neurophysiological recovery was not completed. ...
Introduction: The decision to clear an athlete to return to play (RTP) after a concussion is critical given the potential consequences of premature RTP. Accordingly, this study aimed to investigate more sensitive ways to assess readiness for RTP. We examined postexercise cognitive assessment in recently concussed and asymptomatic university athletes who were cleared to RTP.
Methods: Forty recently concussed athletes and 40 control athletes without a history of concussion participated in the study. Athletes completed a switch task preexercise and postexercise (20 min on an ergometer at 80% maximal heart rate). A series of one-way ANOVA were performed to compare accuracy and response time between the concussion and the control groups on the switch task. Given that the clinical recovery of the participants in the concussion group could be heterogeneous, we also ran χ2 tests to identify the presence of subgroups. Specifically, we aimed to determine whether a group difference existed in the proportion of concussed participants who underperformed.
Results: No difference between the concussion and control groups was observed for reaction time. However, a significant group difference was found for accuracy, with athletes from the concussion group exhibiting lower accuracy relative to the control group. Irrespective of condition (rest, postexercise), up to 30% of athletes from the concussion group were 2 SD lower when compared with the control group's average score. A third of the athletes only exhibited deficits after exercise.
Conclusions: Our results highlight the importance of considering interindividual differences in recovery trajectories. Although asymptomatic and cleared to RTP, an important portion of athletes had not completely recovered from their concussion. Fortunately, these athletes can be readily identified by using sensitive cognitive tests administered after a moderate-to-vigorous exercise.
... ERP's are typically labeled by their polarity (P for positive or N for negative) and their time of occurrence after the stimulus in milliseconds (e.g., P300). Numerous studies have reported ERP-related differences between mTBI and control groups, even as some of these found no differences using neuropsychological measures [19][20][21][22][23][24][25][26][27][28][29]. ...
Purpose:
Electrophysiological event-related potentials (ERP's) have been reported to change after concussion. The objective of this study is to use a simple 2-tone auditory P300 ERP in routine clinical settings to measure changes from baseline after concussion and to determine if these changes persist at return to play when other standard measures have normalized.
Methods:
Three-hundred sixty-four (364) student athletes, aged 17-23 years, participating in contact sports were tracked over consecutive years. In this blinded study P300, plus physical reaction times and Trail Making tests, were collected alongside standard clinical evaluations. Changes in these measures after concussion were compared to clinical outcomes over various stages of post-injury recovery.
Results:
Concussed players experienced significant reaction time and/or P300 amplitude changes compared to pre-concussion baseline measurements (p< 0.005). P300 changes persisted in 38% of the players after standard measures, including reaction times, had cleared. Many of those players slow to normalize were part of the sub-concussive symptom group and/or appeared more prone to repeat concussions.
Conclusion:
These data suggest significant P300 amplitude changes after concussion that are quantifiable and consistent. These changes often normalized slower than other standard assessments. More data are needed to determine if slow normalization relates to sub-concussive or repeated events.
... When using behavioral measures to detect differences between asymptomatic individuals with a remote history of concussion and controls, a null result is common [11,13,29,[51][52][53][54][55][56]. However, interpretation of these results has been difficult due to methodological issues such as experimental design or the heterogeneity of participants. ...
Aim:
We examined the long-term effects of concussions in young adult females on visuomotor behavior during a visually-guided reaching task of various complexities.
Materials & methods:
20 females with a history of longer than 6 months since a concussion and 20 healthy females quickly and accurately performed a delayed reach to a previously cued target.
Results:
As both cognitive and motor load increased, task performance decreased for both groups (p < 0.05). However, contrary to our primary hypothesis, no differences in task performance were found between the two experimental groups (p > 0.05).
Conclusion:
The young adult females with a remote history of concussion demonstrated no deficits in visuomotor behavior on an attention-mediated reaching task as compared with control participants.
... Previous studies have found that the use of more difficult cognitive tasks when assessing a sport-related concussion on cognition when a person is asymptomatic will show larger deficits in domains such as executive function and attention and processing speed [26][27][28]. Ellemberg, et al. [25] found that 6-8 months after initial sport-related concussion those in the concussed group still scored significantly lower on cognitive tasks that measured planning time, inhibition speed and response time, all tasks that would be categorized as executive function or attention and processing speed. In other words, the damage from a sport-related concussion on high level cognitive tasks may still be present well after initial symptoms have conceded than previously reported [29]. ...
... The electrophysiological literature, specifically studies of evoked potentials, has informed this thinking. For example, Broglio, Pontifex, O'Connor, and Hillman (2009) and Kashluba et al. (2008) found that the P300 response, which has been linked to resource allocation (Polich, 2007), was abnormal in young adults 3 years postinjury and who demonstrated deficits. Adults with mTBI also have shown longer P300 latencies and decreased amplitudes than their uninjured peers, despite similar performance (Dupuis, Johnston, Lavoie, Lepore, & Lassonde, 2000;Gaetz & Weinberg, 2000;Gosselin et al., 2012;Lavoie, Dupuis, Johnston, Leclerc, & Lassonde, 2004;Ozen, Itier, Preston, & Fernandes, 2013;Thériault, De Beaumont, Gosselin, Filipinni, & Lassonde, 2009). ...
Purpose
The aim of this study was to characterize language comprehension in mild traumatic brain injury (mTBI) by testing a speed-based hypothesis. We hypothesized that adults with mTBI would perform worse than a group of adults with orthopedic injuries (OIs) on an experimental language comprehension task.
Method
The study employed a prospective experimental design. Participants were 19 adults with mTBI and 19 adults with OI ages 18–55 years. Participants completed the Whatdunit task, a sentence agent selection task in speeded and unspeeded conditions.
Results
In the unspeeded condition, the mTBI group performed with a marginally significant higher accuracy than the OI group. In the speeded condition, the mTBI group performed with lower accuracy than the OI group; however, this difference did not reach statistical significance. There was a marginally significant interaction of Sentence Type × Group for reaction time in the speeded condition.
Conclusions
While our task might have been sensitive to cognitive processing abilities in both groups (as evidenced by the main effects of condition and sentence type), the task was not specific enough to capture mTBI-related deficits. The similarities in performance between both groups have clinical implications for the treatment of not just brain-related trauma but also trauma in general.
... Despite the fact that few of these individuals have hearing outside the normal range on a clinical audiogram, a significant percentage report difficulty understanding speech in background noise as well as difficulty on other complex auditory tasks, such as understanding rapid speech or detecting small gaps in noise (5)(6)(7)(8)(9)(10)(11)(12)(13). Difficulties with these tasks may result from damage to structures in the central auditory pathway from the brainstem to the primary auditory cortex may be vulnerable to mTBI, including auditory brainstem nuclei, structures in the left temporal lobe, pathways between the thalamus and primary auditory cortex, the planum temporale, and the corpus callosum (14)(15)(16). Identifying whether there is electrophysiological evidence of changes in how speech information is represented along the central auditory pathway and whether behavioral deficits correlate with these neural representations is of interest to better understand the long-term auditory consequences of mTBI. ...
Background: The purpose of the study was to examine auditory event-related potential (AERP) evidence of changes in earlier and later stages of auditory processing in individuals with long-term post-concussion problems compared to healthy controls, with a secondary aim of comparing AERPs by functional auditory behavioral outcomes.
Methods: P1-N1-P2 complex and P300 components recorded to speech in quiet and background noise conditions were completed in individuals with ongoing post-concussion symptoms following mTBI and healthy controls. AERPs were also examined between sub-groups with normal or impaired auditory processing by behavioral tests.
Results: Group differences were present for later stages of auditory processing (P300). Earlier components did not significantly differ by group overall but were more affected by noise in the mTBI group. P2 amplitude in noise differed between mTBI sub-groups with normal or impaired auditory processing.
Conclusion: AERPs revealed differences between healthy controls and those with chronic post-concussion symptoms following mTBI at a later stage of auditory processing (P300). Neural processing at the earlier stage (P1-N1-P2) was more affected by noise in the mTBI group. Preliminary evidence suggested that it may be only the proportion of individuals with functional evidence of central auditory dysfunction with changes in AERPs at earlier stages of processing.
... Common symptoms after mTBI include headache, fatigue, forgetfulness, sleep problems, and cognitive dysfunction. Cognitive impairments are evident on both tests of global cognitive abilities (e.g., IQ) (14) and on tests of specific cognitive domains such as attention (15) and speed of information processing (16,17). Stout and colleagues (18) found that when compared to healthy adults, individuals with mTBI showed impairments such as linguistic inefficiency, disorganization, and fewer meaningful content units per minute on experimental tasks, all of which hint at possible information processing deficits. ...
Objective: The purpose of this study was to characterize cognitive-linguistic performance in adults with mild traumatic brain injury (mTBI) to advance assessment and treatment practices. We hypothesized that individuals with mTBI would demonstrate longer reaction times (RTs) and greater error rates when compared to an orthopedic injury (OI) group on a category-naming task.
Method: Participants were age and education-matched adults with mTBI (n = 20; 12 females) and adults with OI (n = 21; 5 females) who were discharged to home after an Emergency Department visit. Our primary task was a category-naming task shown to be sensitive to language deficits after mTBI. The task was adapted and administered under speeded and unspeeded conditions.
Results: There was a significant main effect of condition on RT (speeded faster than unspeeded) and accuracy (more errors in the speeded condition). There was a marginally significant effect of group on errors, with more errors in the mTBI group than the OI group. Naming RT and accuracy in both conditions were moderately correlated with injury variables and symptom burden.
Conclusions: Our data showed a marginal effect of group on accuracy of performance. Correlations found between naming and neurobehavioural symptoms, including sleep quality, suggest that the latter should be considered in future research.
... The presentation and range of symptomatic experiences after a concussion are well-documented and include potential impairment to affect (8)(9)(10)(11), cognition (12)(13)(14)(15), sleep (16)(17)(18), vesitbular-occulomotor (19)(20)(21), and cardiovascular autonomic function (22,23). The challenge for clinicians has been a limited ability to predict the type, number, and severity of symptoms that may emerge, and equally important, how long they persist after a concussion. ...
A difference exists between sexes for the incidence of concussion injuries and severity of post-injury outcomes with females having a higher incidence rate (in comparable sports) and experience more robust symptoms than males. The basis for this disparity has remained largely unresolved. Recent findings point to a potential biological mechanism that may be related to the menstrual cycle as an arbiter of post-injury outcomes. What has not been addressed, is whether the phase of menstrual cycle (inferred fluctuations of ovarian hormones) contributes to an increased vulnerability to sustain a concussion injury. This prospective, observational study sought to determine if concussions occurred at different frequencies throughout the phase of the menstrual cycle. Female athletes who sustained a concussion injury were queried three times over the 7-day study (e.g., within 48 h of injury, and 4 and 7 days after injury) to recall the number of days that have elapsed since the beginning of their most recent menstruation. Twenty female athletes enrolled after sustaining a concussion; 18 were eumenorrheic and 2 amenorrheic. Among eumenorrheic participants at the time of injury, 2 were in the follicular phase, 4 were in the early luteal phase and 9 were in the late luteal phase. Two athletes were injured on the first and 1 was injured on the second day of menstruation. The greatest number of concussions were sustained during the late luteal phase and during the first 2 days of menstruation. This 9-day window accounted for 2/3rd of the sustained concussions in our study.
... Rather, damage to structures along the pathway from the inner ear to the cortex may disrupt encoding and perceptual processing of auditory information in the central auditory nervous system, disrupting speech understanding and other auditory perceptual skills, such as sound localization, auditory discrimination, temporal aspects of audition, and hearing in degraded or noisy conditions. The auditory centers in the brain responsible for these skills are highly vulnerable to mTBI, including structures in the left temporal lobe and pathways between the thalamus and primary auditory cortex, the planum temporale, and the corpus callosum (Broglio, Pontifex, O'Connor, & Hillman, 2009;Cubon, Putukian, Boyer, & Dettwiler, 2011). Existing literature suggests that, across a range of severities, up to 50% of individuals with TBI-related injuries may have central auditory processing problems (Bergemalm & Borg, 2001;Bergemalm & Lyxell, 2005;Flood, Dumas, & Haley, 2005). ...
Purpose
This study examined auditory deficits and symptom reporting in individuals with long-term postconcussion symptoms following a single mild traumatic brain injury (mTBI) compared to age- and gender-matched controls without a history of mTBI.
Method
Case history interviews, symptom questionnaires, and a battery of central auditory and neuropsychological tests were administered to 2 groups. The mTBI group was a civilian population recruited from a local concussion management program who were seeking rehabilitation for postconcussion-related problems in a postacute period between 3 and 18 months following injury. Symptom validity testing was included to assess the rate of possible insufficient test effort and its influence on scores for all outcome measures. Analyses of group differences in test scores were performed both with and without the participants who showed insufficient test effort. Rates of symptom reporting, correlations among symptoms and behavioral test outcomes, and the relationships between auditory and cognitive test performance were analyzed.
Results
The mTBI group reported a high rate of auditory symptoms and general postconcussion symptoms. Performance on neuropsychological tests of cognitive function showed some differences in raw scores between groups, but when effort was considered, there were no significant differences in the rate of abnormal performance between groups. In contrast, there were significant differences in both raw scores and the rate of abnormal performance between groups for some auditory tests when only considering participants with sufficient effort. Auditory symptoms were strongly correlated with other general postconcussion symptoms.
Conclusions
Significant auditory symptoms and evidence of long-term central auditory dysfunction were found in a subset of individuals who had chronic postconcussion symptoms after a single mTBI unrelated to blast trauma. The rate of abnormal performance on auditory behavioral tests exceeded the rate of abnormal performance on tests of cognitive function.
Supplemental Material
https://doi.org/10.23641/asha.8329955
... This is a particularly important highlight of the Fickling et al. (2019) study, which to our knowledge represents the first observation of P300 changes in the early acute phase immediately following concussion (this equally applies to the N100 and N400 components). As Rosburg and Mager (2019) correctly point out, the closest comparison of post-concussive results occurred 1 week after injury (Candrian et al., 2018), with the remainder of P300 studies reviewed by Brush et al. (2018) taking place weeks (Gosselin et al., 2006), months (Dupuis et al., 2000;Gaetz et al., 2000;Lavoie et al., 2004;Thériault et al., 2009;Baillargeon et al., 2012), and the majority, years after injury (De Beaumont et al., 2007Broglio et al., 2009;Pontifex et al., 2009;Ozen et al., 2013;Moore et al., 2014Moore et al., , 2015Moore et al., , 2017Parks et al., 2015;Ledwidge and Molfese, 2016). ...
... Power frequency bands include: Delta: 0.5-4 Hz, Theta: 4 − 8 Hz, Alpha: 8-12 Hz, Beta: 12-20 Hz, Gamma: 20-80 Hz, where common findings associated with concussion are increased alpha, increased delta, and decreased theta (Ianof and Anghinah, 2017;Kenzie et al., 2017;Nuwer et al., 2005;Oster et al., 2010;Sandsmark et al., 2017). Common ERP components that have been studied for sports-related concussions in human subjects include: N2, found at 200-350 ms with a frontal central distribution on the scalp ( Broglio et al., 2009;Ledwidge and Molfese, 2016;Moore et al., 2015); the P3, found at 300-800 ms with a midline parietal distribution ( Baillargeon et al., 2012;De Beaumont et al., 2009;Dupuis et al., 2000; Gosselin et al., 2006;Lavoie et al., 2004;Moore et al., 2016;Moore et al., 2014;Moore et al., 2017;Nandrajog et al., 2017;Ozen et al., 2013;Parks et al., 2015;Theriault et al., 2009); the error-related negativity (ERN) Pontifex et al., 2009), typically occurring at 50-100 ms at the midline frontal and central scalp sites; and the error positivity (eP), which occurs at 200-500 ms following the ERN, typically observed in the midline central and parietal scalp areas ( Brush et al., 2018;Lesiakowski et al., 2018). General trends across research studies denote a decrease in amplitude and increase in latency for ERP components associated with concussed cohorts in comparison with healthy controls, furthermore the P3 or P300 is the most widely used for injury (Brush et al., 2018). ...
Traumatic brain injury is a leading cause of cognitive and behavioral deficits in children in the US each year. There is an increasing interest in both clinical and pre-clinical studies to discover biomarkers to accurately diagnose traumatic brain injury (TBI), predict its outcomes, and monitor its progression especially in the developing brain. In humans, the heterogeneity of TBI in terms of clinical presentation, injury causation, and mechanism has contributed to the many challenges associated with finding unifying diagnosis, treatment, and management practices. In addition, findings from adult human research may have little application to pediatric TBI, as age and maturation levels affect the injury biomechanics and neurophysiological consequences of injury. Animal models of TBI are vital to address the variability and heterogeneity of TBI seen in human by isolating the causation and mechanism of injury in reproducible manner. However, a gap between the pre-clinical findings and clinical applications remains in TBI research today. To take a step toward bridging this gap, we reviewed several potential TBI tools such as biofluid biomarkers, electroencephalography (EEG), actigraphy, eye responses, and balance that have been explored in both clinical and pre-clinical studies and have shown potential diagnostic, prognostic, or monitoring utility for TBI. Each of these tools measures specific deficits following TBI, is easily accessible, non/minimally invasive, and is potentially highly translatable between animals and human outcomes because they involve effort-independent and non-verbal tasks. Especially conspicuous is the fact that these biomarkers and techniques can be tailored for infants and toddlers. However, translation of preclinical outcomes to clinical applications of these tools necessitates addressing several challenges. Among the challenges are the heterogeneity of clinical TBI, age dependency of some of the biomarkers, different brain structure, life span, and possible variation between temporal profiles of biomarkers in human and animals. Conducting parallel clinical and pre-clinical research, in addition to the integration of findings across species from several pre-clinical models to generate a spectrum of TBI mechanisms and severities is a path toward overcoming some of these challenges. This effort is possible through large scale collaborative research and data sharing across multiple centers. In addition, TBI causes dynamic deficits in multiple domains, and thus, a panel of biomarkers combining these measures to consider different deficits is more promising than a single biomarker for TBI. In this review, each of these tools are presented along with the clinical and pre-clinical findings, advantages, challenges and prospects of translating the pre-clinical knowledge into the human clinical setting.
... P for positive and N for negative) and time range in milliseconds. 80 Furthermore, concussed subjects who were, on average, over three years post-injury demonstrated decrements in N2 and P3b amplitudes relative to individuals without a history of concussion, 83 in response to a three-stimulus oddball task, although other research has shown no difference. 84 Nevertheless, the P3 component has been repeatedly shown to have chronic amplitude suppression among multi-concussion athletes. ...
The diagnosis of mild traumatic brain injury in concussion is difficult since it is often unwitnessed, the patient’s recall is unreliable and initial clinical examination is often unrevealing, correlating poorly with the extent of brain injury. At present, there are no objective biomarkers of mild traumatic brain injury in concussion. Thus, a sensitive gold standard test is required to enable the effective and safe triage of patients who present to the acute services. As well as triage, objective monitoring of patients’ recovery over time and separate from clinical features that patients may develop following the injury (e.g. depression and migraine) is also needed. In contrast to neuroimaging, which is widely used to investigate traumatic brain injury patients, electrophysiology is readily available, is cheap and there are internationally recognized standardised methodologies. Herein, we review the existing literature on electrophysiological testing in concussion and mild traumatic brain injury; specifically, electroencephalogram, polysomnography, brainstem auditory evoked potentials, electro- and videonystagmography, vestibular evoked myogenic potentials, visually evoked potentials, somatosensory evoked potentials and transcranial magnetic stimulation.
... When considered alongside the existing literature, the supposition that attentionally demanding tasks are particularly effective for eliciting sports-related concussion decrements in cognition appears well supported. Indeed, a growing body of literature has demonstrated subtle yet persistent deficits in cognition several years following a concussive injury ( Broglio et al., 2009;de Beaumont, Brisson, Lassonde, & Jolicoeur, 2007;Dupuis, John- ston, Lavoie, Lepore, & Lassonde, 2000;Ellemberg et al., 2007;Giza & Hovda, 2001;Guskiewicz et al., 2005;Halterman et al., 2006;D. R. Moore et al., 2016;). ...
Objective:
A critical barrier to the understanding of disruptions to cognitive flexibility following sports-related concussion is the use of assessments that conflate shifts of visuospatial attention and contextual rules. Because these dissociable forms of cognitive flexibility are subserved by distinct neural networks, the utility of a cognitive flexibility assessment following concussion may be reduced, depending upon the extent to which the task requires shifting visuospatial attention relative to shifting contextual rules. Accordingly, the current investigation examined the extent to which these aspects of cognitive flexibility exhibit differential trajectories of recovery following a sports-related concussion.
Method:
Twenty-two athletes with sports-related concussions were assessed on a cognitive flexibility task with 2 switch conditions (i.e., perceptual-based and contextual rule-based) within 72 hr of injury, after return to play, and within 1 month following return to play. Thirty-three healthy control athletes were tested at the same intervals.
Results:
Findings revealed that concussed athletes demonstrated protracted disruptions in task performance on a visuospatial attention-based cognitive flexibility task relative to healthy controls, whereas disruptions in task performance on a contextual rule-based cognitive flexibility task resolved after the acute phase of injury. These findings suggest that dissociable forms of cognitive flexibility exhibit differential trajectories of recovery.
Conclusions:
Therefore, evaluations detecting sports-related concussion disruptions in cognitive flexibility may be reduced depending on the extent to which they rely on contextual rule-based decisions. Test batteries focusing on visuospatial attention-based demands may be useful additions to aid in the objective assessment and follow-up management of athletes following the acute phase of injury. (PsycINFO Database Record
... However, athletes with a concussion history exhibited significantly larger N2 amplitudes, suggesting increased recruitment of inhibitory control processes in order to successfully meet task demands. In contrast, Broglio et al. (2009) reported smaller N2 amplitudes elicited by a three-stimulus oddball task among a group of young athletes with a self-reported history of concussion relative to those athletes who reported no previous concussion history. Moreover, a number of previous studies have not found differences in N2 amplitude or latency to be associated with a history of concussion (e.g., Gaetz et al., 2000;Gosselin et al., 2012;Moore et al., 2016). ...
Previous research has demonstrated long-term deficits in neurocognitive function in individuals with a history of sport-related concussion. The purpose of this study was to examine the relationship between a history of concussion and behavioral and event-related potential (ERP) indices of pre- and post-response conflict and error monitoring. A secondary aim was to determine whether years of high risk sport participation were related to impairments in these cognitive control processes. Forty-seven former athletes (age = 20.8 ± 2.2 years) with (n = 25; 5 females) and without (n = 22; 9 females) a history of concussion completed a modified flanker task while behavioral performance, N2, error-related negativity (ERN), and error positivity (Pe) components were assessed. An increase in post-response error-related (ERN) brain activity and a nonsignificant trend of increased pre-response conflict (N2) was observed in individuals with a prior sport-related concussion relative to non-concussed controls; however, no behavioral performance differences were found between groups. No significant associations were found between ERP and behavioral measures and the number of years of high-risk sport participation; however, time since last head injury was associated with shorter N2 latency. Together, these findings suggest a persistent impairment in cognitive control and error-related processing in individuals with a history of concussion. These findings are interpreted within the framework of the compensatory error-monitoring hypothesis.
... For more comprehensive reviews of the literature regarding ERPs and their use in concussion, please see the reviews by Alderman et al. and Broglio et al. [28,29]. A study by Broglio et al. compared the ERPs of a group of young adults with a concussion history to a group without a concussion history (N = 90, 19.7 ± 1.3 years: 44 without concussion and 46 with previous concussion)-a novelty oddball task [30]. The results showed decreased N2 and P3b latencies in the group with a concussion history relative to the control group. ...
Sports-related concussions are an increasing public health issue with much concern about the possible long-term decrements in cognitive function and quality of life that may occur in athletes. The measurement of cognitive function is a common component of concussion management protocols due to cognitive impairments that occur after sustaining a concussion; however, the tools that are often used may not be sensitive enough to expose long term problems with cognitive function. The current paper is a brief review, which suggests that measuring cognitive processing through the use of event related potentials (ERPs) may provide a more sensitive assessment of cognitive function, as shown through recent research showing concussion history to influence ERPs components. The potential influence of genetics on cognitive function and ERPs components will also be discussed in relation to future concussion management.
Our study aimed at detecting a potential cumulative effect of subsequent concussions on the neural activation patterns of young rugby athletes with or without concussion history. Event-related brain potential (ERP) data from 24 rugby players, 22-year-old on average, were retrospectively examined. All underwent a Sport Concussion Assessment Tool (SCAT2) during preseason and an on-site ERP task (P300) following a recent concussion event (<48 hours). Sixteen players suffered at least one concussion in the previous 3 years and eight were without self-reported past concussion. While no differences were reported between groups regarding symptom appraisal on the SCAT2 assessment, ERP revealed significantly decreased P3b amplitude and a trend for increased P3b latency in players who experienced prior concussions. Our data thus support the cumulative effect of concussions on neuroelectric events in young rugby players, highlighting the importance of managing player's concussion load to reduce the risk of long-term injuries.
Purpose:
Numerous studies have reported electrophysiological differences between concussed and non-concussed groups, but few studies have systematically explored recovery trajectories from acute concussion to symptom recovery and the transition from acute concussion to prolonged phases. Questions remain about recovery prognosis and the extent to which symptom resolution coincides with injury resolution. This study therefore investigated the electrophysiological differences in recoveries between simple and complex concussion.
Methods:
Student athletes with acute concussion from a previous study (19(2) years old) were tracked from pre-injury baseline, 24-48 hours after concussion, and through in-season recovery. The electroencephalography (EEG) with P300 evoked response trajectories from this acute study were compared to an age-matched population of 71 patients (18(2) years old) with prolonged post-concussive symptoms (PPCS), 61 (SD 31) days after concussion.
Results:
Acute, return-to-play, and PPCS groups all experienced a significant deficit in P300 amplitude compared to the pre-injury baseline group. The PPCS group, however, had significantly different EEG spectral and coherence patterns from every other group.
Conclusion:
These data suggest that while the evoked response potentials deficits of simple concussion may persist in more prolonged stages, there are certain EEG measures unique to PPCS. These metrics are readily accessible to clinicians and may provide useful parameters to help predict trajectories, characterize injury (phenotype), and track the course of injury.
Objective
Individuals with a concussion history tend to perform worse on dual-tasks compared controls but the underlying neural mechanisms contributing to these deficits are not understood. This study used event-related potentials (ERPs) to investigate sensory gating and cognitive processing in athletes with and without a history of concussion while they performed a challenging dual-task.
Methods
We recorded sensory (P50, N100) and cognitive (P300) ERPs in 30 athletes (18 no previous concussion; 12 history of concussion) while they simultaneously performed an auditory oddball task and a working memory task that progressively increased in difficulty.
Results
The concussion group had reduced auditory performance as workload increased compared to the no-concussion group. Sensory gating and cognitive processing were reduced in the concussion group indicating problems with filtering relevant from irrelevant information and appropriately allocating resources. Sensory gating (N100) was positively correlated with cognitive processing (P300) at the hardest workload in the no-concussion group but negatively correlated in the concussion group.
Conclusion
Concussions result in long-term problems in behavioral performance, which may be due to poorer sensory gating that impacts cognitive processing.
Significance
Problems effectively gating sensory information may influence the availability or allocation of attention at the cognitive stage in those with a concussion.
Language deficits and alterations to the N400 ERP are commonly reported in aphasia and moderate-to-severe traumatic brain injury (TBI), but have seldomly been investigated after mild TBI, such as concussion. In the present study, the N400 was recorded from young adults within 1-month after concussion and matched controls during a sentence processing task. The N400 recorded to semantically incongruent sentence-final words was significantly more negative and with a more anterior distribution in the concussion group than control group. Among the concussion group, a weaker N400 was associated with more concussion symptoms, slower response time, and poorer executive functioning. Multiple regression results showed that concussion occurrence and male gender were independently associated with a more negative N400-effect, whereas symptoms were associated with a weaker N400. These findings provide novel evidence that alterations to lexical-semantic networks may occur after concussion and vary based on individual differences in post-concussion symptoms and cognitive function.
The present study investigated executive function and sustained attention of non-athlete, young adults (ages 18–23) with a history of concussion beyond ten months post incident. Cognitive functioning was examined in 24 non-athletic, college students with a concussion history (mean age 21 yrs.; mean time and range post-injury: 4 years, 10–90 months) and 24 non-athletic controls with no history (NH) of concussion. Computerized versions of two cognitive assessment techniques were utilized to examine executive functioning (Stroop) and sustained attention capacity (D2). Primary dependent variables were response time, error score, and sustained attention score. Relationships between dependent variables and concussion metrics were also analyzed. ANOVA’s revealed a significantly higher error rate in concussion history (CH) participants when performing the Stroop task (p < 0.05), including a trend for greater errors in the incongruent task condition (p < 0.05). Group measures did not differ in the sustained attention test (all p > 0.05). Nevertheless, there was a significant relationship between D2 error rate and time since concussion (p < 0.01), showing that D2 error rate was greater for participants with more time since concussion sustainment. Our findings indicate the potential for prolonged cognitive dysfunction linked to decision-making, but not to processing speed, in young adult non-athletes with a CH averaging four years post-injury. These findings may provide evidence of residual cognitive deficits in young adults with a concussion history over time.
Traumatic brain injury (TBI) at all levels, from concussion through severe TBI, can negatively impact multiple systems in the human body. This multisystem disturbance is evidenced by the distributed nature and complex symptom patterns of TBI individuals including brain-based symptoms such as cognitive deficits and emotional lability, as well as autonomic symptoms such as headache, nausea, and dizziness. In order to properly diagnose, predict prognosis, and guide recovery, assessment following TBI must include all physiologic systems that may have disrupted function following TBI, and must include the use of appropriate tools in order to administer a comprehensive assessment. Electrophysiology is the only available tool that directly reflects real-time neurological function through the measurement of the moment-to-moment electrical discharges of firing neurons. Tools such as event-related potentials (ERPs), derived from the electroencephalogram, and heart rate variability, derived from the electrocardiogram, are reliable, valid, and clinically available tools that have decades of research and clinical support for their use in evaluating the underlying pathophysiology of TBI on nervous system function. This chapter reviews ERP and autonomic nervous system biomarkers that have demonstrated utility in assessment and recovery tracking for individuals suffering TBI.
Objective:
Jockeys have high rates of concussion, with 5% of jockeys receiving at least one concussion annually. The impact of acute concussion upon cognition is well understood, but less is known about the long-term effects of concussion upon cognition. Our aim was to assess the impact of concussion upon jockeys who had provided pre-concussion assessments of cognition using a prospective design.
Method:
In this study, over a 5-year period, we assessed the cognitive performance of jockeys with ≥1 medically diagnosed concussion (MDC; n = 17, months since concussion, M = 29.18), against those who had not been concussed (NC; n = 41). Jockeys who had not been concussed in the preceding 6 months completed four computer-based cognitive assessments from the CogSport battery.
Results:
Unlike the majority of the small existing literature, there was no difference (p ≥ .05) between the MDC and NC groups after controlling for age and baseline performance. Additionally, we used a measure of reliable change to assess for clinically meaningful decrements from baseline in each test and composite score 5 years later. None of the jockeys in the MDC group recorded significant decrements on any CogSport measure from baseline (z > -1.65).
Conclusions:
The findings suggest that the presence of concussion does not result in persistent decrements in cognitive performance and that when findings are considered collectively, assessing factors beyond medically diagnosed concussion (e.g., chronic stress, undiagnosed concussion) may improve the interpretation of our current findings.
Concussion and Traumatic Encephalopathy - edited by Jeff Victoroff February 2019
Concussion and Traumatic Encephalopathy - edited by Jeff Victoroff February 2019
Cambridge Core - Psychiatry - Concussion and Traumatic Encephalopathy - edited by Jeff Victoroff
Concussion and Traumatic Encephalopathy - edited by Jeff Victoroff February 2019
Objectives:
This report examined theta-band neurodynamics for potential biomarkers of brain health in athletes with concussion.
Methods:
Participants included college-age contact/collision athletes with (N=24) and without a history of concussion (N=16) in Study 1. Study 2 (N=10) examined changes over time in contact/collision athletes. There were two primary dependent variables: (1) theta-band phase-synchronization (e.g., functional connectivity) between medial and right-lateral electrodes; and (2) the within-subject correlation between synchronization strength on error trials and post-error reaction time (i.e., operationalization of cognitive control).
Results:
Head injury history was inversely related with medial-lateral connectivity. Head injury was also related to declines in a neurobehavioral measure of cognitive control (i.e., the single-trial relationship between connectivity and post-error slowing).
Conclusions:
Results align with a theory of connectivity-mediated cognitive control. Mild injuries undetectable by behavioral measures may still be apparent on direct measures of neural functioning. This report demonstrates that connectivity and cognitive control measures may be useful for tracking recovery from concussion. Theoretically relevant neuroscientific findings in healthy adults may have applications in patient populations, especially with regard to monitoring brain health. (JINS 2019, 25, 314-323).
Despite increasing use of pupillometry to understand cognitive deficits in clinical populations, there is no consensus on what pupillary metrics are most useful. In this study, we compare the reliability, sensitivity to mild traumatic brain injury (TBI) and cognitive load differences, and the likelihood of replication between various pupillary metrics. Raw pupil diameter was recorded from 15 patients with chronic mild TBI and 23 uninjured controls while they performed a cognitive task with three levels of cognitive load. Several pupillary metrics were quantified from the pupillary data and submitted to tests of internal consistency, group ∗ cognitive load repeated measures ANOVAs, and bootstrapping analyses of effect size. Most pupillary metrics demonstrated acceptable, good, or excellent reliability. Metrics differed in sensitivity to group, cognitive load, and their interaction. Bootstrapping analyses revealed that peak-based metrics are more likely to replicate than means- or ratio-based metrics. Several pupillary metrics were determined to have great utility for measuring cognitive load in clinical or normative samples. This study directly addresses a known methodological gap in the cognitive pupillometry literature.
Objectives:
Research on the cognitive sequelae of mild traumatic brain injury (mTBI) suggests that, despite generally rapid recovery, difficulties may persist in the domain of cognitive control. The goal of this study was to examine whether individuals with chronic blast-related mTBI show behavioral or neural alterations associated with cognitive control.
Methods:
We collected event-related functional magnetic resonance imaging (fMRI) data during a flanker task in 17 individuals with blast-related mTBI and 16 individuals with blast-exposure without TBI (control).
Results:
Groups did not significantly differ in behavioral measures of cognitive control. Relative to the control group, the mTBI group showed greater deactivation of regions associated with the default mode network during the processing of errors. Additionally, error processing in the mTBI group was associated with enhanced negative coupling between the default mode network and the dorsal anterior cingulate cortex as well as the dorsolateral prefrontal cortex, regions of the salience and central executive networks that are associated with cognitive control.
Conclusions:
These results suggest that deactivation of default mode network regions and associated enhancements of connectivity with cognitive control regions may act as a compensatory mechanism for successful cognitive control task performance in mTBI. (JINS, 2018, 24, 1-11).
Annually, 1.6-3.8 million concussions occur from sports in the United States, which account for 5-9% of all sports injuries. The dangers of concussions include prolonged post-concussive symptoms, increased risk of subsequent concussions, seizures, mental health issues, and in cases of second-impact syndrome (SIS), possible death. Certified Athletic Trainers (ATC) continue to serve an important role in providing assessment and treatments for athletes with sports-related injuries. They provide a critical safety net due to limited knowledge and misconceptions of concussion held by some youth sports coaches and athletes. However, availability of services from ATCs in rural areas is a challenge. In order to help extend coverage to more rural student athletes, we propose designing a telemedicine app following the mHealth development roadmap from the Center for eHealth Research (CeHRes). In this paper we will document contextual inquiry, user requirements capture, design phases, and app evaluation from the targeted user base.
Notes that to understand the endogenous components of the event-related potential (ERP), data about the components' antecedent conditions to form hypotheses about the information-processing function of the underlying brain activity must be used. These hypotheses generate testable predictions about the consequences of the component. The application of this approach to the analysis of the P300 component is reviewed. Certain factors suggest that P300 is a manifestation of activity occurring whenever one's model of the environment must be revised. Tests of 3 predictions based on this "context updating" model are reviewed. Open peer commentary follows. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The triarchic model of P300 amplitude (Johnson, 1986, 1988a) postulated that the overall amplitude of the P300 recorded at any given electrode site represented the summation of activity from different neural generators, each related to the processing of a different type of information. However, neither of these original accounts provided an explicit description of the methods required to establish experimentally the presence of multiple neural sources. This paper reviews the triarchic amplitude model, the subsequently obtained data that support the postulated presence of multiple generators underlying the P300, and the methods used to demonstrate the presence of these multiple sources. These methods are straightforward because it is only necessary to show that the portions of P300 amplitude associated with different experimental variables have different scalp distributions. The implications of the multiple-generator basis of P300 on such factors as component definition, neural source analyses, and the cognitive processes underlying its activity are discussed.
A technique for measuring the latency of the P300 component of event-related brain potentials on individual trials is described.
Choice reaction times and the latency of the P300 were compared under speed-maximizing and under accuracy-mazimising instructions.
The choice stimuli required different levels of semantic categorization. The data support the proposition that the latency
of P300 corresponds to stimulus evaluation time and is independent of response selection.
Despite the high prevalence and potentially serious outcomes associated with concussion in athletes, there is little systematic research examining risk factors and short- and long-term outcomes.
To assess the relationship between concussion history and learning disability (LD) and the association of these variables with neuropsychological performance and to evaluate postconcussion recovery in a sample of college football players.
A total of 393 athletes from 4 university football programs across the United States received preseason baseline evaluations between May 1997 and February 1999. Subjects who had subsequent football-related acute concussions (n = 16) underwent neuropsychological comparison with matched control athletes from within the sample (n = 10).
Clinical interview, 8 neuropsychological measures, and concussion symptom scale ratings at baseline and after concussion.
Of the 393 players, 129 (34%) had experienced 1 previous concussion and 79 (20%) had experienced 2 or more concussions. Multivariate analysis of variance yielded significant main effects for both LD (P<.001) and concussion history (P=.009), resulting in lowered baseline neuropsychological performance. A significant interaction was found between LD and history of multiple concussions and LD on 2 neuropsychological measures (Trail-Making Test, Form B [P=.007] and Symbol Digit Modalities Test [P=.009]), indicating poorer performance for the group with LD and multiple concussions compared with other groups. A discriminant function analysis using neuropsychological testing of athletes 24 hours after acute in-season concussion compared with controls resulted in an overall 89.5% correct classification rate.
Our study suggests that neuropsychological assessment is a useful indicator of cognitive functioning in athletes and that both history of multiple concussions and LD are associated with reduced cognitive performance. These variables may be detrimentally synergistic and should receive further study.
Our understanding of developmental changes in attentional selection in the growing child has been advanced substantially by the results of (a relatively small number of) studies undertaken from a psychophysiological perspective. The basic outcome of these studies is that, in attentional filtering as well as selective set (the two basic paradigms in attention research), the processes necessary for attentional selection are in essence available even to the young child; however, the speed and efficiency of these processes tends to increase as the child grows into an adolescent. Under optimal conditions, filtering is performed at early stages of information processing, but less optimal stimulus characteristics and task requirements may induce a shift in the locus of selection to later processing stages for young children whereas older individuals are better able to preserve their early locus of selection. When early selection is constrained, young children are substantially more sensitive to the adverse effects of response competition. In selective set, sub-optimal conditions lead not so much to a shift in locus of selection processes, but to a shift in the age at which asymptote efficiency is attained. We have proposed hierarchical regression analysis as a useful technique to examine whether age-related differences in attention effects, as observed in specific ERP components and in RT, are reflections of an age effect on a single source of attentional selection or of separate sources that each contribute uniquely to the developmental trends seen in (attention effects on) RT. Re-analyses of existing data demonstrated that (again depending on task specifics) many but not all of the different component processes involved in attentional selection contributed unique variance to the age-related changes in attention effects.
We have used event-related potentials (ERP) to assess cerebral activity following mild traumatic brain injuries in 20 college athletes practising contact sports. Concussion victims showed a striking decrease in P300 amplitude, an effect presumed to reflect alterations in attentional-cognitive processes. Moreover, the degree of impairment was strongly related to the severity of post-concussion symptoms. Our data suggest that concussions cause objectively measurable changes in the electrophysiological markers of brain activity and hence in the functions of the structures from which they originate. ERPs may thus constitute a reliable method to accurately monitor the clinical course and recovery of head injuries in athletes.
Lack of empirical data on recovery time following sport-related concussion hampers clinical decision making about return to play after injury.
To prospectively measure immediate effects and natural recovery course relating to symptoms, cognitive functioning, and postural stability following sport-related concussion.
Prospective cohort study of 1631 football players from 15 US colleges. All players underwent preseason baseline testing on concussion assessment measures in 1999, 2000, and 2001. Ninety-four players with concussion (based on American Academy of Neurology criteria) and 56 noninjured controls underwent assessment of symptoms, cognitive functioning, and postural stability immediately, 3 hours, and 1, 2, 3, 5, 7, and 90 days after injury.
Scores on the Graded Symptom Checklist (GSC), Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and a neuropsychological test battery.
No player with concussion was excluded from participation; 79 players with concussion (84%) completed the protocol through day 90. Players with concussion exhibited more severe symptoms (mean GSC score 20.93 [95% confidence interval [CI], 15.65-26.21] points higher than that of controls), cognitive impairment (mean SAC score 2.94 [95% CI, 1.50-4.38] points lower than that of controls), and balance problems (mean BESS score 5.81 [95% CI, -0.67 to 12.30] points higher than that of controls) immediately after concussion. On average, symptoms gradually resolved by day 7 (GSC mean difference, 0.33; 95% CI, -1.41 to 2.06), cognitive functioning improved to baseline levels within 5 to 7 days (day 7 SAC mean difference, -0.03; 95% CI, -1.33 to 1.26), and balance deficits dissipated within 3 to 5 days after injury (day 5 BESS mean difference, -0.31; 95% CI, -3.02 to 2.40). Mild impairments in cognitive processing and verbal memory evident on neuropsychological testing 2 days after concussion resolved by day 7. There were no significant differences in symptoms or functional impairments in the concussion and control groups 90 days after concussion.
Collegiate football players may require several days for recovery of symptoms, cognitive dysfunction, and postural instability after concussion. Further research is required to determine factors that predict variability in recovery time after concussion. Standardized measurement of postconcussive symptoms, cognitive functioning, and postural stability may enhance clinical management of athletes recovering from concussion.
Although concussion is common among athletes, evidence-based methods for clinical evaluation, treatment, and recovery are lacking. We used a prospective, functional neuroimaging approach to assess sports-related concussion in which imaging was performed before injury so that brain changes resulting from concussion could be better understood.
Neurophysiologic correlates of sports-related concussion were investigated in eight college football players by using functional MR imaging. Preseason baseline levels of blood oxygen level-dependent (BOLD) activity were acquired during the performance of a test battery that included mathematical, memory, and sensorimotor coordination tasks. Four players who had a concussion repeated these baseline procedures within 1 week of injury. The remaining control players were retested at the end of the season.
Specific neural signatures of concussion were detected in individual players by comparing postconcussion results to preconcussion baseline values. The validity of these indicators was confirmed by comparing them with the same measures in noninjured control subjects. When compared with control subjects, concussed players had marked within-subject increases in the amplitude and extent of BOLD activity during a finger-sequencing task. Effects were observed primarily in the parietal and lateral frontal and cerebellar regions.
Differences in neural functioning were observed in the absence of observed deficits in behavioral performance, suggesting that this approach may increase sensitivity to concussion compared with neuropsychological evaluation alone. Though preliminary, the proposed prospective neuroimaging approach may have great potential for understanding mild traumatic brain injury and identifying mechanisms underlying recovery.
Neuropsychological testing is a valuable tool in concussion diagnosis and management. ImPACT, a computerized neuropsychological testing program, consists of eight cognitive tasks and a 21-item symptom inventory.
ImPACT was used to examine the cognitive performance of 104 concussed athletes at baseline, 2, 7 and 14 days post-injury. Dependent measures included composite scores from the ImPACT computerized test battery, as well as a total symptom score from the Post-Concussion Symptom Scale.
Differences between baseline and day 2 post-injury scores were observed for all ImPACT composites (Verbal memory-VERM, visual memory-VISM, processing speed-PROC and reaction time-RT) as well as in total symptom score (SX). At day 7, concussed athletes continued to perform significantly poorer on VERM, VISM, RT and SX. At day 14, only VERM scores were significantly different from baseline.
Cognitive performance deficits in concussed athletes may persist to 7 and even to 14 days in some cases. In addition to symptom status, the athlete's post-concussion cognitive functioning should be considered when making return-to-play decisions.
The purpose of this study was to illustrate the serial use of computerized neuropsychological screening with ImPACT to monitor recovery in a clinical case series of injured athletes.
Amateur athletes with concussions (n= 30, average age= 16.1, SD= 2.1 years) underwent pre-season testing and three post-concussion evaluations within the following intervals: 1-2 days, 3-7 days (M= 5.2 days) and 1-3 weeks (M= 10.3 days). The study selection criteria increased the probability of including athletes with slow recovery.
Repeated measures ANOVAs revealed significant main effects for all five composite scores (verbal memory, visual memory, reaction time, processing speed and total symptoms). In group analyses, performance decrements and symptoms relating to concussion appeared to largely resolve by 5 days post-injury and fully resolve by 10 days. Athletes' scores were examined individually using the reliable change methodology. At 1 day post-injury, 90% had two or more reliable declines in performance or increases in symptom reporting. At 10 days, 37% were still showing two or more reliable changes from pre-season levels.
This study illustrates the importance of analysing individual athletes' test data because group analyses can obscure slow recovery in a substantial minority of athletes.
The long term effects of self reported concussion on neurocognitive functioning have been found to be variable.
To evaluate cognitive performance on the Headminder concussion resolution index (CRI) and ImPACT assessment tests of subjects with and without a history of self reported concussion.
A retrospective analysis was completed on 235 Headminder CRI baseline assessments and 264 ImPACT baseline assessments. Participants were divided into four groups on the basis of reported number of concussions (zero, one, two, or three). Multivariate analysis of variance was used to evaluate differences between the concussion history groups on the two computer based concussion assessment programs.
Multivariate analysis of variance indicated no significant difference between those with and without a history of concussion on the CRI (Lambda = 0.963, F((15, 627.05)) = 0.57, p = 0.898). It also revealed no significant differences between groups on the ImPACT test (Lambda = 0.951, F((12, 672.31)) = 1.07, p = 0.381).
The results suggest that either long term cognitive decrements may not be associated with a history of concussion or the decrements may be subtle and undetectable by these computer programs.
Interpretation of the cellular and molecular pathogenic basis of post-minimal traumatic brain injury is a significant clinical and scientific problem, especially due to the high prevalence of motor vehicle--and other accidents. Pathogenetic brain mechanisms following traumatic impact are usually investigated by using models of severe or moderate trauma. Apoptotic neuronal degeneration after notable brain trauma is a well-known phenomenon, but the source of its activation is not clear, especially after mild, subclinical brain trauma. In the present study, we used a closed head weight-drop model to induce minimal brain injury in mice. Pellets of 5, 10, 15, 20, 25 and 30 g were dropped on the right side of mice's head kept under light ether anesthesia. No abnormal behavioral or neurophysiological changes were seen following the head trauma. Morphological assessment was done 72 h after the traumatic impact using TUNEL assay and silver staining. We found gradual increase of TUNEL-positive and silver-impregnated cells number in different cortical and hippocampal regions of both injured and contralateral hemispheres. The threshold of traumatic impact that caused a significant activation was 10-15 g pellets (evident by silver staining), and 15-20 g for apoptosis. The most sensitive zones for trauma were anterior cingulate cortex and CA3 area of hippocampus. No bilateral hemispheric differences were found. Our results demonstrate that even closed head minimal traumatic brain injury can cause diffused neuronal damage and apoptosis. This results correlate well with cognitive and behavioral deficits described for mice suffering similar mTBI and can also explain the wide variety of mental disturbances described for post-concussion syndrome in patients who suffered mild head injury.
Recommendations for the improvement of safety and health of athletes who may suffer concussive injuries
In November 2001, the first International Symposium on Concussion in Sport was held in Vienna, Austria. This symposium was organised by the International Ice Hockey Federation (IIHF), the Federation Internationale de Football Association Medical Assessment and Research Centre (FIFA, F-MARC), and the International Olympic Committee Medical Commission (IOC).
The aim of the symposium was to provide recommendations for the improvement of safety and health of athletes who suffer concussive injuries in ice hockey, football (soccer), and other sports. To this end a range of experts were invited to address specific issues of epidemiology, basic and clinical science, grading systems, cognitive assessment, new research methods, protective equipment, management, prevention, and long term outcome, and to discuss a unitary model for understanding concussive injury. At the conclusion of the conference, a small group of experts were given a mandate by the conference delegates and organising bodies to draft a document describing the agreement position reached by those in attendance at that meeting. For the purpose of this paper, this group will be called the Concussion in Sport Group (CISG).
This review seeks to summarise the findings of the Vienna conference and to provide a working document that will be widely applicable to sport related concussion. This document is developed for use by doctors, therapists, health professionals, coaches, and other people involved in the care of injured athletes, whether at the recreational, elite, or professional level.
During the course of the symposium, a persuasive argument was made that a comprehensive systematic approach to concussion would be of potential benefit to aid the injured athlete and direct management decisions.1 This protocol represents a work in progress, and, as with all other guidelines or proposals, it must undergo revision …
The contribution of prefrontal and posterior association cortex to voluntary and involuntary visual attention was as sessed using electrophysiological techniques in patients with focal lesions in prefrontal (n = 11), temporal-parietal (n = 10), or lateral parietal cortex (n = 7). Subjects participated in a task requiring detection of designated target stimuli embedded in trains of repetitive stimuli. Infrequent and irrelevant novel visual stimuli were randomly interspersed with the target and background stimuli. Controls generated attention dependent N1 (170 msec) and N2 (243 msec) potentials maximal over extrastriate cortex. Anterior and posterior association cortex lesions reduced the amplitude of both the N1 and N2 potentials recorded over extrastriate cortex of the lesioned hemisphere. The pattern of results obtained reveals that an intrahemispheric network involving prefrontal and posterior association cortex modulates early visual processing in extrastriate regions. Voluntary target detection generated a parietal maximal P300 response (P3b) and irrelevant novel stimuli generated a more frontocentrally distributed P300 (P3a). Cortical lesions had differential effects on P3a and P3b potentials. The P3b was not significantly reduced in any cortical lesioned group. Conversely, the P3a was reduced by both prefrontal and posterior lesions with decrements most severe throughout the lesioned hemisphere. These data provide evidence that an association cortex network involving prefrontal and posterior regions is activated during orientation to novel events. The lack of a significant effect on the visual target P3b in patients with novelty P3a reductions supports the notion that different neural systems are engaged during voluntary vs involuntary atten- tion to visual stimuli.
Reports on experiments that investigated the locus of the effect of stimulus probability on choice RT and the locus of interference in performance on the Stroop Color–Word Test. When P300 latency was used to index stimulus-evaluation time, both stimulus- and response-processing were affected by stimulus probability—more probable events were identified faster, and responses to them were emitted more rapidly. With the Stroop task, response competition appears to be the primary source of Stroop interference. (49 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Topics include: introduction (evolutionary origin of mind–body integration, the role of psychophysiology, caveats: limitations of the convergent indicator paradigm); views of the autonomic nervous system (the classical view, autonomic balance, role of the vagus, autonomic space, central lateralized control of autonomic responses); attention and the autonomic nervous system (introduction: a stimulus-rich environment, varieties of attention); the orienting reflex (Russian origins, habituation of the orienting reflex, elicitation of the orienting reflex, theories of habituation: critical role of the comparator, stimulus significance and elicitation of the orienting reflex, an information-processing model of orienting, the efferent link: physiological markers of the orienting reflex and the defense reflex); voluntary attention: anticipation of impending stimuli (the conception of the Laceys, Obrist and cardiac-somatic coupling, evaluation of the Lacey-Obrist controversy, anticipatory HR deceleration and motor processes); and Pavlovian conditioning of autonomic responses. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The P300 event-related brain potential (ERP) was elicited with auditory and visual stimuli in two different tasks. The oddball paradigm presented both target and standard stimuli; the single-stimulus paradigm presented a target but no standard stimulus, with the intertarget interval the same as that for the oddball condition. Target probability was .20 for the oddball task, with target stimuli occurring at the same temporal frequency in the single-stimulus paradigm. Scalp topography was assessed with 15 electrode locations. P300 amplitude was larger and latency was longer for the oddball than for single-stimulus procedure. P300 from auditory stimuli was smaller and shorter in latency than that from the visual stimuli, and both modalities showed similar but not identical scalp topographies. The findings suggest that the single-stimulus paradigm may be useful in experimental and applied contexts that require very simple ERP task conditions.
McCarthy and Donchin (1981) found that the latency of a late positive component of the event-related potential (ERP) was influenced by the presence of noise in a stimulus matrix but not by the compatibility between the stimulus presented and the response required. They concluded that this component is a P300 and that its latency was influenced by stimulus evaluation but not by response selection processes. The present experiments were designed to confirm that the component identified by McCarthy and Donchin was indeed a P300 and to determine if its latency varies systematically with increases in stimulus evaluation time produced by graded changes in noise level.
The nature of the psychophysiological enterprise is examined as it bears on the study of the endogenous components of event-related brain potentials (ERP). The view is taken that success in Psychophysiology should be measured by the degree to which psychophysiological data can be used in elucidating the processes that underly the behavioral product rather than by the enumeration of psychophysiological “correlates” of behavior. It is proposed that endogenous ERP components are best viewed as manifestations of the activities of “subroutines” invoked during the informational transactions of the brain.
A theoretical account of an ERP component consists of the specification of the functional role of the subroutine it manifests. Studies of the P300 components are examined for the contribution they make to the development of such a theory of the P300. Experiments focusing on P300 latency and amplitude are reviewed and it is concluded that P300 may be a manifestation of the processes whereby schemas are revised. The relationship between P300 and the Orienting Reflex is discussed within the framework of this model. It is suggested that P300 amplitude may predict the memorability of events. A preliminary test of this prediction is described.
The present review focuses on the utility of the amplitude of P3 of as a measure of processing capacity and mental workload. The paper starts with a brief outline of the conceptual framework underlying the relationship between P3 amplitude and task demands, and the cognitive task manipulations that determine demands on capacity. P3 amplitude results are then discussed on the basis of an extensive review of the relevant literature. It is concluded that although it has often been assumed that P3 amplitude depends on the capacity for processing task relevant stimuli, the utility of P3 amplitude as a sensitive and diagnostic measure of processing capacity remains limited. The major factor that prompts this conclusion is that the two principal task variables that have been used to manipulate capacity allocation, namely task difficulty and task emphasis, have opposite effects on the amplitude of P3. I suggest that this is because, in many tasks, an increase in difficulty transforms the structure or actual content of the flow of information in the processing systems, thereby interfering with the very processes that underlie P3 generation. Finally, in an attempt to theoretically integrate the results of the reviewed studies, it is proposed that P3 amplitude reflects activation of elements in a event-categorization network that is controlled by the joint operation of attention and working memory.
Experiments were conducted to study the contribution of prefrontal cortex to the generation and modulation of two varieties of P300 activity. Control subjects generated typical parietal maximal P300 responses to detected target stimuli. Unexpected, novel auditory stimuli presented to controls generated an earlier latency, fronto-centrally distributed P300 response. A similar earlier latency, fronto-central P300 is generated to unexpected, novel visual stimuli. The occurrence of this phenomenon in both the auditory and visual modalities suggests that it may reflect neural activity of a common CNS system involved in the orienting response.
Management of a sport-related concussion, especially involving return-to-play decisions, is one of the most important challenges confronting sports medicine professionals. Current guidelines result from thoughtful consensus recommendations by expert committees but are chiefly based on the resolution of symptoms and the results of neuropsychological testing, if available. Adherence to this paradigm results in most injured athletes resuming competition in 1 to 2 weeks.
Two distinct late-positive components of the scalp-recorded auditory evoked potential were identified which differed in their latency, scalp topography and psychological correlates. The earlier component, called "P3a" (latency about 240 msec), was elicited by infrequent, unpredictable shifts of either intensity or frequency in a train of tone pips whether the subject was ignoring (reading a book) or attending to the tones (counting). The later component, called "P3a" (mean latency about 350 msec), occurred only when the subject was actively attending to the tones; it was evoked by the infrequent, unpredictable stimulus shifts, regardless of whether the subject was counting that stimulus or the more frequently occurring stimulus. Both of these distinct psychophysiological entities have previously been refered to as the "P3" or "P300" in the literature.
The P300 event-related potential was elicited with auditory stimuli in 4 experiments which manipulated combinations of stimulus target probability (10% vs. 30%), task difficulty (easy vs. hard), and inter-stimulus interval (5 sec vs. 2 sec). P300 amplitude was smaller and peak latency longer for the more difficult relative to the easier tasks across experiments. Increases in stimulus target probability generally diminished P300 amplitude and shortened peak latency more for the easy relative to difficult task conditions. Increasing the number of non-target stimulus tones decreased P300 amplitude reliably, but increased latency only slightly. Task difficulty did not interact with variations in inter-stimulus interval which produced generally weak effects for both amplitude and latency. These findings suggest that P300 amplitude and latency obtained from auditory discrimination paradigms reflect processing difficulty independently of stimulus target probability unless differences in task requirements affect stimulus encoding.
Postmortem examination was performed on 137 residents (average age 85.5 years) of a skilled nursing facility whose mental status, memory, and functional status had been evaluated during life. Seventy-eight percent were demented using conservative criteria; 55% had characteristic Alzheimer's disease. Choline acetyltransferase and somatostatin were significantly reduced in the brains of patients with Alzheimer's disease as compared with age-matched nursing home control subjects, although the degree of the reduction was less severe than found in subjects less than 80 years of age. Ten subjects whose functional and cognitive performance was in the upper quintile of the nursing home residents, as good as or better than the performance of the upper quintile of residents without brain pathology (control subjects), showed the pathological features of mild Alzheimer's disease, with many neocortical plaques. Plaque counts were 80% of those of demented patients with Alzheimer's disease. Choline acetyltransferase and somatostatin levels were intermediate between controls and demented patients with Alzheimer's disease. The unexpected findings in these subjects were higher brain weights and greater number of neurons (greater than 90 micron 2 in a cross-sectional area in cerebral cortex) as compared to age-matched nursing home control subjects. These people may have had incipient Alzheimer's disease but escaped loss of large neurons, or alternatively, started with larger brains and more large neurons and thus might be said to have had a greater reserve.
The need for a simply applied quantitative assessment of handedness is discussed and some previous forms reviewed. An inventory of 20 items with a set of instructions and response- and computational-conventions is proposed and the results obtained from a young adult population numbering some 1100 individuals are reported. The separate items are examined from the point of view of sex, cultural and socio-economic factors which might appertain to them and also of their inter-relationship to each other and to the measure computed from them all. Criteria derived from these considerations are then applied to eliminate 10 of the original 20 items and the results recomputed to provide frequency-distribution and cumulative frequency functions and a revised item-analysis. The difference of incidence of handedness between the sexes is discussed.
The theoretical and empirical backgrounds for the utility of the P300 event-related potential (ERP) as a measure of cognitive aging are summarized. P300 latency data from 32 different normative aging studies are then reviewed and assessed with meta-analytic procedures. Evaluation of moderator variables indicates that sample characteristics, stimulus factors, and task conditions contribute significantly to the "normal" change in peak latency that occurs with aging. These findings are critiqued in the context of previous reports, and implications are outlined for future applications of ERPs to normative aging. It is concluded that P300 latency can provide useful information about cognitive aging but that specific variables must be considered to obtain more precise results.
The stimulus evaluation view on P3 latency holds that P3 latency mainly reflects stimulus-processing time, in contrast to response-processing time. A review of the experimental evidence, however, leads to the conclusion that P3 is not a sensitive tool for separating between stimulus- and response-related processes. Rather, it appears that P3 latency is a sensitive index of any response-time changes when response times in the fast condition are brief, with its sensitivity decreasing when response times in the fast condition get longer. This regularity was confirmed by a detailed analysis of the published evidence from Sternberg's task and was not attributable to speed-accuracy trade-off or to different methods of parametrization. The structures generating the scalp P3b are involved both in stimulus processing and in response selection. Response selection may exert its effect on P3 in one of two ways; either directly, fully delaying P3 latency, or affecting a second P3 component (P-CR) only, thus having an attenuated effect on P3 latency.
EEG was recorded from 120 normal adult subjects who ranged in age from 20 to 80+ years in separate eyes open/closed conditions. The P3(00) event-related brain potential (ERP) was elicited with auditory and visual stimuli in separate conditions in the same subjects. Spectral analysis indicated that overall EEG power decreased as subject age increased. P3 amplitude decreased and peak latency increased for both the auditory and visual stimulus conditions as subject age increased. Few age-related differences were observed for the N1, P2, or N2 components. Spectral power from the delta, theta, and alpha bands correlated positively with P3 amplitude across subject age, but mean band frequency demonstrated only weak associations with P3 latency. No strong relationships were found between EEG and the other ERP component variables. The results suggest that age contributes to EEG power shifts, and that such changes significantly affect age-related variability of the P3 ERP component.