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Do the Eyes Have It? Can Consideration of Concussion Variants Improve Management?



A concussion can be considered a disorder of information processing. Concussions are currently viewed as a homogenous condition. The wide range of signs and symptoms associated with concussion syndromes suggest there may be variants of subtypes of concussion. The mainstream recommendations for concussion management suggest physical and cognitive rest on the presumption that decreased stimuli will allow restoration of cellular homeostasis in the neural tissue. We believe adding computer gaming glasses to the treatment of concussed patients with prominent visual symptoms follows the same line of reasoning and will prove to be an effective management technique. We also suggest that targeted management interventions aimed at other prominent symptoms present in a concussed patient may improve recovery.
Curr Res Concussion Vol 2 No 2 Summer 2015 61
JM Lynch, S Stanley Green. Do the eyes have it? Can consideration
of concussion variants improve management? Curr Res Concussion
A concussion can be considered to be a disorder of information processing.
Concussions are currently viewed as a homogenous condition. The wide
range of signs and symptoms associated with concussion syndromes suggest
there may be variants of subtypes of concussion. The mainstream recom-
mendations for concussion management suggest physical and cognitive rest
on the presumption that decreased stimuli will allow restoration of cellular
homeostasis in the neural tissue. The authors believe that adding computer
gaming glasses to the treatment of concussed patients with prominent
visual symptoms follows the same line of reasoning and will prove to be an
effective management technique. They also suggest that targeted manage-
ment interventions aimed at other prominent symptoms present in a con-
cussed patient may improve recovery.
Key Words: Computer glasses; Concussion; Concussion management; Gaming
glasses; Postconcussion syndrome
Do the eyes have it? Can consideration of concussion
variants improve management?
James M Lynch MD, Sue Stanley Green MS ATC LAT
Concussions have witnessed a remarkable increase in media
attention over the past decade. Concussions are brain injuries
that are considered to be diffuse in nature, rather than focal and
structural. A concussion is a traumatically induced alteration in
brain function (1-4) that can be summarized as a disorder of informa-
tion processing (5). Concussions occur frequently within the sport-
ing arena, with the incidence varying among sports (6). Concussions
are also a common occurrence in occupational settings and motor
vehicle collisions, accounting for a significant number of visits to
emergency departments.
There are a variety of symptoms associated with concussion includ-
ing dizziness and vertigo, difficulty concentrating, light sensitivity,
headaches, depression, difficulty sleeping, irritability, word-finding
difficulty, impulsiveness and amnesia (7,8). Difficulty concentrating
and feeling slowed down are often prominent symptoms during the
first week after a concussion (7). The assortment of clinical symptoms
that occur in individuals with concussion or postconcussion syndrome
has not correlated well with the mechanism of injury or the cellular
Concussions have traditionally been viewed as a uniform condi-
tion. In previous decades, health care professionals evaluated the pres-
ence and severity of symptoms at time of presentation to establish the
diagnosis and determine a grade. The grade and history of previous
concussion then established a definitive time period for restriction of
activity. Recent recommendations emphasize the length of time symp-
toms are present, rather than the initial severity, as the crucial factor
in concussion diagnosis and management (1-4).
The constellation of symptoms actually present in any individual is
currently of secondary importance, conveying the perspective of uni-
formity in concussion. Contemporary management is not changed
across the range of symptoms. Complaints of headache versus light
sensitivity, dizziness or depression do not significantly change the
protocol used for management.
The brain is a complex organ, with the various structures accom-
plishing differing functions. The injury forces involved in concussions
have unique vectors that may traverse different parts of the brain. The
variety of symptoms in concussion and postconcussion syndromes has
sparked consideration of subtypes in both conditions and prompted
attempts to categorize symptoms into groups (8-11). These subtypes are
most commonly grouped into some version of three categories: cogni-
tive, somatic and emotional/behavioural symptoms (8-10). Subsequent
treatment may be tailored to the particular symptom complex or clas-
sification an individual patient is experiencing. Our group believes the
treatment of visual symptoms will be one of these differentiations.
Cerebral concussions involve a cascade of metabolic changes that occur
at the cellular level of the brain (12). The initial injury causes a change
in membrane permeability, resulting in abnormal distribution of ions
across the axon and excessive excitatory neurotransmitter release. The
restoration of normal ion and neurotransmitter distribution requires a
great deal of cellular energy from ATP to power the sodium-potassium
pump. This requires increased glucose metabolism to support the accel-
erated energy demand (12).
Other cell components begin to malfunction later in the cascade.
Increased intracellular calcium concentration results in mitochondrial
dysfunction, worsening the energy crisis. The calcium increase also
disrupts neurofilaments and microtubules, impairing neural connectiv-
ity (12). The altered cellular homeostasis accompanies the energy
imbalance (13). As clinical symptoms resolve, it can be presumed that
cellular homeostasis is re-established. Postconcussion syndrome may
occur with a failure to restore homeostasis.
Symptoms generally resolve within 21 days, with the majority of
concussions resolving in seven to 10 days (13,14). Adolescent athletes
appear to experience a longer recovery time than mature athletes (14-
16). A significant percentage of patients diagnosed with concussions
experience persistent symptoms (13,17). Ten percent to 20% of con-
cussed patients experience symptoms that last >2 weeks, whereas
approximately 2% experience symptoms that last weeks to months
(18,19). The incidence may be higher in emergency room patients
presenting with concussion (20).
Visual symptoms are included in one of the three categories often
used to describe the proposed subtypes of concussion, although visual
symptoms may be placed in the cognitive or somatic category (21-26).
The visual system is located throughout the brain, from the retina and
optic chiasm anteriorly to the occipital lobe posteriorly, with several
crucial structures in between. Injury forces are likely to involve some
of the numerous components of the visual system. Visual changes,
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Florida Southern College, Lakeland, Florida, USA
Correspondence: Dr James M Lynch, Florida Southern College, 111 Lake Hollingsworth Drive, Lakeland, Florida 33801, USA.
Telephone 863-680-6205, fax 863-680-4251, e-mail
Lynch and Stanley Green
Curr Res Concussion Vol 2 No 2 Summer 201562
including increased photosensitivity and photophobia, have been
reported in concussion patients (21-26). A high incidence of visual
dysfunction has been reported in soldiers who sustain mild traumatic
brain injury (mTBI) following blast injuries (25). Vestibular ocular
dysfunction has also been noted in a large percentage of sport-related
concussion (27).
The diagnosis of concussion was made through clinical examination
historically. Neuropsychological means have been added to the regi-
men over the past couple of decades. Balance testing gained popularity
with the Balance Error Scoring System test (28). Inroads have been
made with identifying serum biomarkers associated with concussion,
although this remains in its infancy (29).
A brief vestibular ocular assessment was able to differentiate
between concussed and nonconcussed patients (27). The increasingly
popular King-Devick test uses a simple timed test to assess visual sac-
cades as well as concentration and language function in patients with
concussions (30-32). Eye tracking technology has been shown to be
accurate in detecting third and sixth cranial nerve palsies in brain
injured patients (33). There is not yet documentation of the utility of
eye tracking in concussion but the prevalence of identified dysfunc-
tion (21-27) suggests that eye tracking technologies will be helpful.
Treatment options for concussion are limited (34), with mainstream
recommendations emphasizing physical and cognitive rest (14). There
is some question as to the necessity or efficacy of prescribed rest
(16,35,36). A recent report with a strong research design (36) suggests
that more rest is not better. Other therapies have had limited efficacy
and/or have had limited research designs. The more successful treat-
ment strategies have focused on a particular symptom complex (34).
Our group recently reported two adolescent athletes suffering post-
concussion syndrome with debilitating symptoms of one years’ dur-
ation, which adversely affected both academic and sports activity (5).
The dominant symptom complex in each involved the visual system.
Both patients began using computer gaming glasses (Gunnar Optiks,
Inc, USA) with resolution of symptoms (5). We have subsequently
used the gaming glasses with success in three of four collegiate athletes
with prominent visual symptoms following a concussion.
The brand of glasses (Gunnar Optiks) we chose appeared to have
the highest quality with the best pricing (Figure 1). The frame style
was left to each patient’s preference to increase the likelihood of use.
This brand of computer gaming glasses has a patented amber tint that
filters nearly 100% of blue light at 400 nm to 45% of blue light in the
450 nm wavelength. Blue light in the 400 nm to 450 nm wavelength
range activates s-cones in the retina. The focal area of the lens has a
flatter and wider midpoint, lessening the need for accommodation
(focusing) at a distance of 51 cm to 61 cm (20 in to 24 in), the typical
viewing distance for a computer monitor.
The present report provides an interesting suggestion but does not
constitute a definitive recommendation. We believe additional data
from a variety of researchers are necessary to determine whether the
use of computer gaming glasses is a reasonable recommendation for
concussion management on a larger scale.
The incidence of visual dysfunction in concussion has a strong base
in the literature (21-27); however, additional work specifically
addressing sport-related concussion will be useful. Investigation of the
particular types of visual dysfunction should also be addressed in future
studies. Vestibulo-ocular deficits (27), oculomotor deficits of vergence,
version and accommodation (alignment, tracking and focusing) (25)
have all been demonstrated previously. Abnormalities in visual sac-
cades are the premise underlying the success of the King-Devick test
(30-32). Functional magnetic resonance imaging in the presence of
these abnormalities will provide some fascinating data. The efficacy of
computer gaming glasses should be evaluated in a randomized con-
trolled trial of concussed patients with visual symptoms.
We also believe the same principles can be applied to other prom-
inent symptoms of concussion to improve management. An obvious
example is the use of noise-cancelling headphones in patients who
demonstrate noise sensitivity.
The mainstream recommendations for concussion management sug-
gest physical and cognitive rest on the presumption that decreased
stimuli will allow restoration of cellular homeostasis in the neural tis-
sue. We believe adding computer gaming glasses to the treatment of
concussed patients with prominent visual symptoms follows the same
line of reasoning and will prove to be an effective management tech-
nique. We also suggest that targeted management interventions aimed
at other prominent symptoms present in a concussed patient may
improve recovery.
DISCLOSURES: The authors have no financial disclosures or conflicts
of interest to declare.
1. Giza CC, Kutcher JS, Ashwal S, et al. Summary of evidence-based
guideline update: evaluation and management of concussion in
sports: Report of the Guideline Development Subcommittee of the
American Academy of Neurology. Neurology 2013;80:2250-7.
2. Harmon KG, Drezner JA, Gammons M, et al. American Medical
Society for Sports Medicine position statement: Concussion in
sport. Br J Sports Med 2013;47:15-26.
3. McCrory P, Meeuwisse W, Aubry M, et al. Consensus statement on
concussion in sport – the 4th International Conference on
Concussion in Sport held in Zurich, November 2012.
Clin J Sport Med 2013;23:89-117.
4. Halstead ME, Walter KD, Council on Sports Medicine and Fitness;
American Academy of Pediatrics. Clinical report:
Sport-related concussion in children and adolescents.
Pediatrics 2010;126:597-615.
5. Lynch JM, Anderson MA, Benton B, Stanley Green S.
The gaming of concussions: A unique intervention in post-
concussion syndrome. J Athletic Train 2015;50:270-6.
6. Marar M, McIlvain NM, Fields SK, Comstock RD. Epidemiology of
concussions among United States high school athletes in 20 sports.
Am J Sports Med 2012;40:747-55.
7. Kontos AP, Elbin RJ, Shatz P, et al. A revised factor structure for
the Post-Concussion Symptom Scale: Baseline and postconcussion
factors. Am J Sports Med 2012;40:2375-84.
8. DeKosky ST, Ikonomovic MD, Gandy S. Traumatic brain injury:
Football, warfare, and long-term effects. N Engl J Med
9. Piland SG, Motl RW, Guskiewicz KM, McCrea M, Ferrara MS.
Structural validity of a self-report concussion-related symptom scale.
Med Sci Sports Exerc 2006;38:27-32.
Figure 1) Gaming glasses (photo courtesy of Gunnar Optiks, Inc, USA)
Consideration of concussion variants
Curr Res Concussion Vol 2 No 2 Summer 2015 63
10. Potter S, Leigh E, Wade D, Fleminger S. The Rivermead Post
Concussion Symptoms Questionnaire: A confirmatory factor
analysis. J Neurol 2006;253:1603-14.
11. Cicerone KD, Kalmar K. Persistent postconcussion syndrome:
The structure of subjective complaints after mild traumatic brain
injury. J Head Trauma Rehabil 1995;10:1-17.
12. Giza CC, Hovda DA. The neurometabolic cascade of concussion.
J Athl Train 2001;36:228-35.
13. McCrory P, Meeuwisse WH, Echemendia RJ, Iversen GL, Dvorak J,
Kutcher JS. What is the lowest threshold to make a diagnosis of
concussion? Br J Sports Med 2013;47:268-71.
14. Moser RS, Glatts C, Schatz P. Efficacy of immediate and delayed
cognitive and physical rest for treatment of sports-related
concussion. J Pediatr 2012;161:922-6.
15. Field M, Collins MW, Lovell MR, Maroon J. Does age play a role in
recovery from sports-related concussion? A comparison of high
school and collegiate athletes. J Pediatr 2003;142:546-53.
16. Majerske CW, Mihalik JP, Ren D, et al. Concussion in sports:
Postconcussive activity levels, symptoms, and neurocognitive
performance. J Athl Train 2008;43:265-74.
17. Bohnen N, Twijnstra A, Jolles J. Persistence of postconcussional
symptoms in uncomplicated mildly head-injured patients:
A prospective cohort study. Neuropsychiatry Neuropsychol
Behav Neurol 1993;6:193-200.
18. McCrea M, Guskiewicz K, Randolph C, et al. Incidence, clinical
course, and predictors of prolonged recovery time following sport
related concussion in high school and college athletes.
J Int Neuropsychol Soc 2013;19:22-33.
19. Makdissi M, Darby D, Maruff P, Ugoni A, Brukner P, McCrory PR.
Natural history of concussion in sport: Markers of severity and
implications for management. Am J Sports Med 2010;38:464-71.
20. Bazarian JJ, Wong T, Harris M, Leahey N, Mookerjee S, Dombovy M.
Epidemiology and predictors of post-concussive syndrome after minor
head injury in an emergency population. Brain Inj 1999;13:173-89.
21. Waddell PA, Gronwall DM. Sensitivity to light and sound following
minor head injury. Acta Neurol Scand 1984;69:270-6.
22. Halterman CI, Langan J, Drew A, et al. Tracking the recovery of
visuospatial attention deficits in mild traumatic brain injury.
Brain 2006;129:747-53.
23. Stovner LJ, Schrader H, Mickeviciene D, Surkiene D, Sand T.
Headache after concussion. Eur J Neurol 2009;16:112-20.
24. Heitger MH, Jones RD, Macleod AD, Snell DL, Frampton CM,
Anderson TJ. Impaired eye movements in post-concussion
syndrome indicate suboptimal brain function beyond the influence
of depression, malingering or intellectual ability.
Brain 2009;132:2850-70.
25. Cap´o-Aponte JE, Urosevich TG, Temme LA, Tarbett AK,
Sanghera NK. Visual dysfunctions and symptoms during the
subacute stage of blast-induced mild traumatic brain injury.
Mil Med 2012;177:804-13.
26. Doble JE, Feinberg DL, Rosner MS, Rosner AJ. Identification of
binocular vision dysfunction (vertical heterophoria) in traumatic
brain injury patients and effects of individualized prismatic spectacle
lenses in the treatment of postconcussive symptoms: A retrospective
analysis. PMR 2010;2:244-53.
27. Mucha A, Collins MW, Elbin RJ, et al. A brief vestibular/ocular
motor screening (VOMS) assessment to evaluate concussions:
Preliminary findings. Am J Sports Med 2014:42:2479-86.
28. Riemann BL, Guskiewicz KM. Effects of mild head injury on
postural stability as measured through clinical balance testing.
J Athl Train 2000;35:19-25.
29. Siman R, Shahim P, Tegner Y, Blennow K, Zetterberg H, Smith DH.
Serum SNTF increased in concussed professional ice hockey players
and relates to the severity of the post-concussion symptoms.
J Neurotrauma 2015 May 14. (Epub ahead of print).
30. Galetta MS, Galetta KM, McCrossin J, et al. Saccades and memory:
Baseline associations of the King-Devick and SCAT2 SAC tests in
professional ice hockey players. J Neurol Sci 2013;328:28-31.
31. Galetta KM, Barret J, Allen M, et al. The King-Devick test as a
determinant of head trauma and concussion in boxers and MMA
fighters. Neurology 2011;76:1456-62.
32. Galetta KM, Brandes LE, Maki K, et al. The King-Devick test and
sports-related concussion: Study of a rapid visual screening tool in a
collegiate cohort. J Neurol Sci 2011;309:34-9.
33. Samadani U, Farooq S, Ritlop R, et al. Detection of third and sixth
cranial nerve palsies with a novel method for eye tracking while
watching a short film clip. J Neurosurg 2015:122:707-20.
34. Leddy JJ, Sandhu J, Sodhi V, Baker JG, Willer B. Rehabilitation of
concussion and post-concussion syndrome. Sports Health
35. Kirkwood MW, Randolph C, Yeates KO. Sport-related concussion:
A call for evidence and perspective amidst the alarms.
Clin J Sport Med 2012;22:383-4.
36. Thomas, DG, Apps JN, Hoffmann RG, McCrea M, Hammeke T.
Benefits of strict rest after acute concussion: A randomized
controlled trial. Pediatrics 2016:135:213-23.
... It is equally important to differentiate between adult and youth athletes, since age is known to affect eye tracking performance (Leigh and Zee 2015) and considered a modifying factor for SRC Giza and Hovda 2014;Iverson et al. 2017). Thus, not only are the concussion rates often higher in youth athletes compared to adult athletes (McCrory et al. 2017;Purcell 2005) but the adolescent years might represent the greatest period of susceptibility to longer recovery times and more pronounced symptoms (Baillargeon et al. 2012;DeMatteo et al. 2015;Iverson et al. 2017;Lynch et al. 2015;Rivara and Graham 2014). Yet eye tracking test-retest reliability studies in youth athletes are virtually nonexistent. ...
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Eye movements that are dependent on cognition hold promise in assessing sports-related concussions but research on reliability of eye tracking measurements in athletic cohorts is very limited. This observational test–retest study aimed to establish whether eye tracking technology is a reliable tool for assessing sports-related concussions in youth and adult athletes partaking in contact and collision team sports. Forty-three youth (15.4 ± 2.2 years) and 27 adult (22.2 ± 2.9 years) Rugby Union and soccer players completed the study. Eye movements were recorded using SMIRED250mobile while participants completed a test battery twice, with a 1-week interval that included self-paced saccade (SPS), fixation stability, memory-guided sequence (MGS), smooth pursuit (SP), and antisaccades (AS) tasks. Intra-class correlation coefficient (ICC), measurement error (SEM) and smallest real difference (SRD) were calculated for 47 variables. Seventeen variables achieved an ICC > 0.50. In the adults, saccade count in SPS had good reliability (ICC = 0.86, SRD = 146.6 saccades). In the youth, the average blink duration in MGS had excellent reliability (ICC = 0.99, SRD = 59.4 ms); directional errors in AS tasks and gain of diagonal SP had good reliability (ICC = 0.78 and 0.77, SRD = 25.3 and 395.1%, respectively). Four metrics were found in this study to be reliable candidates for further biomarker validity research in contact and collision sport cohorts. Many variables failed to present a sufficient level of robustness for a practical diagnostic tool; possibly, because athletic cohorts have higher homogeneity, along with latent adverse effects of undetected concussions and repetitive head impacts. Since reliability of a measure can influence type II error, effect sizes, and confidence intervals, it is strongly advocated to conduct dedicated reliability evaluations prior to any validity studies.
... A t least 3.8 million persons in the United States sustain a concussion every year, many of whom have experienced a previous concussion. 1 As with a number of other health conditions, the presentation of concussion symptoms can vary greatly among the concussed population. 2,3 Some individuals exhibit very little to no change in function and might report no symptoms at all. Others experience confusion, headache, decreased balance, and vision disturbances including blurry vision, trouble focusing, and sensitivity to light. ...
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Context: After a concussion or mild traumatic brain injury (mTBI), patients often suffer from light sensitivity, or photophobia, which contributes to decreased quality of life post-mTBI. Whereas sunglasses may provide some relief from photophobia, they are not practical indoors or in low light. A light-mitigation strategy that can be easily used indoors as needed to optimize the relief. We have found that many photophobic patients experience relief using colored sunglasses. Objective: To provide the athletic trainer with a means and method to assess whether an athlete is suffering from photophobia after concussion and to determine if colored glasses provide relief. Design: Cross-sectional study. Setting: Rehabilitation clinic. Patients or other participants: Fifty-one patients being treated after concussion. Intervention(s): We assessed postconcussion patients for visual symptoms including photophobia and photosensitivity. Off-the-shelf glasses were used to determine whether specific colors provided relief from photophobia. Screening was done using a penlight and multiple colored glasses. Main outcome measure(s): Self-reported mitigation of photophobia symptoms and the specific color frequency that reduced symptoms in each individual. Results: Of the 39 patients studied who had vision symptoms, 76% complained of photophobia. Using glasses of 1 or more colors, symptoms were relieved in 85% of patients reporting photophobia. The colors that provided the most relief were blue, green, red, and purple. No adverse events were reported. Conclusions: An empirical assessment of frequency-specific photophobia is easy to perform. A traditional penlight is used to elicit photophobia and then the colored glasses are tested for optimal relief. Frequency-specific photophobia can be reduced with a strategy of light-mitigation therapy, including colored glasses, sunglasses, hats, and light avoidance. This, we believe, helps to improve the patients' quality of life and may aid in the recovery process. More work is needed to identify the best colors and methods of mitigating frequency-specific photophobia.
Objective: The development of objective quantitative tools for the assessment and monitoring of sports-related concussion is critical. Eye tracking is a novel tool that may provide suitable metrics. The aim of this review was to appraise current evidence for the use of eye tracking technology in sports-related concussion assessment and monitoring. Approach: A systematic literature review was conducted following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. A search was run using Google Scholar, Microsoft Academic and PubMed for literature published between January 1980 and May 2018. Included were empirical research studies in English where at least 50% of the research participants were athletes, the participants were individuals with a diagnosis of concussion, and eye movements were measured using an eye tracking device. Main results: This systematic review integrates 21 publications on sports-related concussion and eye tracking technology, nine of which also qualified for the meta-analysis. Overall, the literature reported significant findings for variables in each of the four classes of eye tracking measurements (movement, position, count, and latency). Meta-comparison was made for seven variables for the acute concussions (the difference between the concussed and the control groups was significant for all of them) and one variable for the latent concussions (the difference was not significant). Significance: Most saccadic and pursuit deficits may be missed during clinical examination, and therefore eye tracking technology may be a useful and sensitive screening and monitoring tool for sports-related concussions. The inconsistencies between the eye movement metrics and methodology still make inferences challenging; however, using tasks that are closely related to brain areas involved in executive functions (such as memory-based saccade or antisaccade tasks) in the acute injury phase holds promise in differentiating between athletes who have a concussion compared to those who do not.
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To determine if recommending strict rest improved concussion recovery and outcome after discharge from the pediatric emergency department (ED). Patients aged 11 to 22 years presenting to a pediatric ED within 24 hours of concussion were recruited. Participants underwent neurocognitive, balance, and symptom assessment in the ED and were randomized to strict rest for 5 days versus usual care (1-2 days rest, followed by stepwise return to activity). Patients completed a diary used to record physical and mental activity level, calculate energy exertion, and record daily postconcussive symptoms. Neurocognitive and balance assessments were performed at 3 and 10 days postinjury. Sample size calculations were powered to detect clinically meaningful differences in postconcussive symptom, neurocognitive, and balance scores between treatment groups. Linear mixed modeling was used to detect contributions of group assignment to individual recovery trajectory. Ninety-nine patients were enrolled; 88 completed all study procedures (45 intervention, 43 control). Postdischarge, both groups reported a 20% decrease in energy exertion and physical activity levels. As expected, the intervention group reported less school and after-school attendance for days 2 to 5 postconcussion (3.8 vs 6.7 hours total, P < .05). There was no clinically significant difference in neurocognitive or balance outcomes. However, the intervention group reported more daily postconcussive symptoms (total symptom score over 10 days, 187.9 vs 131.9, P < .03) and slower symptom resolution. Recommending strict rest for adolescents immediately after concussion offered no added benefit over the usual care. Adolescents' symptom reporting was influenced by recommending strict rest. Copyright © 2015 by the American Academy of Pediatrics.
Full-text available
Object: Automated eye movement tracking may provide clues to nervous system function at many levels. Spatial calibration of the eye tracking device requires the subject to have relatively intact ocular motility that implies function of cranial nerves (CNs) III (oculomotor), IV (trochlear), and VI (abducent) and their associated nuclei, along with the multiple regions of the brain imparting cognition and volition. The authors have developed a technique for eye tracking that uses temporal rather than spatial calibration, enabling detection of impaired ability to move the pupil relative to normal (neurologically healthy) control volunteers. This work was performed to demonstrate that this technique may detect CN palsies related to brain compression and to provide insight into how the technique may be of value for evaluating neuropathological conditions associated with CN palsy, such as hydrocephalus or acute mass effect. Methods: The authors recorded subjects' eye movements by using an Eyelink 1000 eye tracker sampling at 500 Hz over 200 seconds while the subject viewed a music video playing inside an aperture on a computer monitor. The aperture moved in a rectangular pattern over a fixed time period. This technique was used to assess ocular motility in 157 neurologically healthy control subjects and 12 patients with either clinical CN III or VI palsy confirmed by neuro-ophthalmological examination, or surgically treatable pathological conditions potentially impacting these nerves. The authors compared the ratio of vertical to horizontal eye movement (height/width defined as aspect ratio) in normal and test subjects. Results: In 157 normal controls, the aspect ratio (height/width) for the left eye had a mean value ± SD of 1.0117 ± 0.0706. For the right eye, the aspect ratio had a mean of 1.0077 ± 0.0679 in these 157 subjects. There was no difference between sexes or ages. A patient with known CN VI palsy had a significantly increased aspect ratio (1.39), whereas 2 patients with known CN III palsy had significantly decreased ratios of 0.19 and 0.06, respectively. Three patients with surgically treatable pathological conditions impacting CN VI, such as infratentorial mass effect or hydrocephalus, had significantly increased ratios (1.84, 1.44, and 1.34, respectively) relative to normal controls, and 6 patients with supratentorial mass effect had significantly decreased ratios (0.27, 0.53, 0.62, 0.45, 0.49, and 0.41, respectively). These alterations in eye tracking all reverted to normal ranges after surgical treatment of underlying pathological conditions in these 9 neurosurgical cases. Conclusions: This proof of concept series of cases suggests that the use of eye tracking to detect CN palsy while the patient watches television or its equivalent represents a new capacity for this technology. It may provide a new tool for the assessment of multiple CNS functions that can potentially be useful in the assessment of awake patients with elevated intracranial pressure from hydrocephalus or trauma.
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Abstract Biomarkers for diffuse axonal injury could have utilities for the acute diagnosis and clinical care of concussion, including those related to sports. The calpain-derived alpha-spectrin N-terminal fragment SNTF accumulates in axons after traumatic injury, and increases in human blood following mild traumatic brain injury (mTBI) in relation to white matter abnormalities and persistent cognitive dysfunction. However, SNTF has never been evaluated as a biomarker for sports-related concussion. Here, we conducted longitudinal analysis of serum SNTF in professional ice hockey players, 28 of whom had a concussion, along with 45 players evaluated during the preseason, 17 of whom were also tested after a concussion-free training game. Compared to preseason levels, serum SNTF increased at 1 hour after concussion and remained significantly elevated from 12 hours to 6 days, before declining to preseason baseline. In contrast, serum SNTF levels were unchanged after training. In eight players, post-concussion symptoms resolved within a few days, and in these cases serum SNTF levels were at baseline. On the other hand, for the 20 players withheld from play for 6 days or longer, serum SNTF levels rose from 1 hour to 6 days post-concussion, and at 12-36 hours differed significantly from the less severe concussions (p=.004). Serum SNTF exhibited diagnostic accuracy for concussion, especially so with delayed return to play (AUC = 0.87). Multivariate analyses of serum SNTF and tau improved the diagnostic accuracy, the relationship with the delay in return to play, and the temporal window beyond tau alone. These results provide evidence that blood SNTF, a biomarker for axonal injury after mTBI, may be useful for diagnosis and prognosis of sports-related concussion, and for guiding neurobiologically-informed decisions on return to play.
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Objective: To present the case of 2 adolescent high school student–athletes who developed postconcussion syndrome with protracted and limiting visual complaints that markedly affected academic, social, and athletic activity for a year after the onset of symptoms. Both had significant improvement soon after a unique intervention was administered. Background: A 14-year-old female soccer and softball player sustained 2 concussions in the same week. She had persistent symptoms for a year that affected her grades and precluded athletic participation. A 15-year-old male football player sustained a concussion during an altercation with 2 other male adolescents. He continued to have symptoms 1 year later, with a marked decrease in academic performance and restriction from athletics. Both adolescents reported blurry vision, photophobia, and associated headache as significant components of the postconcussion syndrome. Differential Diagnosis: Concussion, postconcussion syndrome, skull fracture, subdural hematoma, epidural hematoma, second-impact syndrome, and visually sensitive migraine. Treatment: Both patients were advised to obtain computer gaming glasses to use throughout the day. The female patient was diligent in her use of the glasses, with marked lessening of symptoms. The male patient was less accepting of the glasses but did report lessening of symptoms when using the glasses. Uniqueness: We hypothesized that postconcussion syndrome with marked visual complaints would respond to and improve with decreased stimulation of the visual system. This was attempted with the addition of computer gaming glasses. Both adolescent athletes responded well to the filtering of visual stimuli by off-the-shelf computer gaming glasses. Conclusions: Postconcussion syndrome is a persistent condition with a myriad of symptoms. Two young athletes developed postconcussion syndrome with prominent visual symptoms that lasted a year. The addition of computer gaming glasses markedly lessened symptoms in both patients.
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Unlabelled: PURPOSE OF THE STATEMENT: ▸ To provide an evidence-based, best practises summary to assist physicians with the evaluation and management of sports concussion. ▸ To establish the level of evidence, knowledge gaps and areas requiring additional research. Importance of an amssm statement: ▸ Sports medicine physicians are frequently involved in the care of patients with sports concussion. ▸ Sports medicine physicians are specifically trained to provide care along the continuum of sports concussion from the acute injury to return-to-play (RTP) decisions. ▸ The care of athletes with sports concussion is ideally performed by healthcare professionals with specific training and experience in the assessment and management of concussion. Competence should be determined by training and experience, not dictated by specialty. ▸ While this statement is directed towards sports medicine physicians, it may also assist other physicians and healthcare professionals in the care of patients with sports concussion. Definition: ▸ Concussion is defined as a traumatically induced transient disturbance of brain function and involves a complex pathophysiological process. Concussion is a subset of mild traumatic brain injury (MTBI) which is generally self-limited and at the less-severe end of the brain injury spectrum. Pathophysiology: ▸ Animal and human studies support the concept of postconcussive vulnerability, showing that a second blow before the brain has recovered results in worsening metabolic changes within the cell. ▸ Experimental evidence suggests the concussed brain is less responsive to usual neural activation and when premature cognitive or physical activity occurs before complete recovery the brain may be vulnerable to prolonged dysfunction. Incidence: ▸ It is estimated that as many as 3.8 million concussions occur in the USA per year during competitive sports and recreational activities; however, as many as 50% of the concussions may go unreported. ▸ Concussions occur in all sports with the highest incidence in football, hockey, rugby, soccer and basketball. RISK FACTORS FOR SPORT-RELATED CONCUSSION: ▸ A history of concussion is associated with a higher risk of sustaining another concussion. ▸ A greater number, severity and duration of symptoms after a concussion are predictors of a prolonged recovery. ▸ In sports with similar playing rules, the reported incidence of concussion is higher in female athletes than in male athletes. ▸ Certain sports, positions and individual playing styles have a greater risk of concussion. ▸ Youth athletes may have a more prolonged recovery and are more susceptible to a concussion accompanied by a catastrophic injury. ▸ Preinjury mood disorders, learning disorders, attention-deficit disorders (ADD/ADHD) and migraine headaches complicate diagnosis and management of a concussion. Diagnosis of concussion: ▸ Concussion remains a clinical diagnosis ideally made by a healthcare provider familiar with the athlete and knowledgeable in the recognition and evaluation of concussion. ▸ Graded symptom checklists provide an objective tool for assessing a variety of symptoms related to concussions, while also tracking the severity of those symptoms over serial evaluations. ▸ Standardised assessment tools provide a helpful structure for the evaluation of concussion, although limited validation of these assessment tools is available. Sideline evaluation and management: ▸ Any athlete suspected of having a concussion should be stopped from playing and assessed by a licenced healthcare provider trained in the evaluation and management of concussions. ▸ Recognition and initial assessment of a concussion should be guided by a symptoms checklist, cognitive evaluation (including orientation, past and immediate memory, new learning and concentration), balance tests and further neurological physical examination. ▸ While standardised sideline tests are a useful framework for examination, the sensitivity, specificity, validity and reliability of these tests among different age groups, cultural groups and settings is largely undefined. Their practical usefulness with or without an individual baseline test is also largely unknown. ▸ Balance disturbance is a specific indicator of a concussion, but not very sensitive. Balance testing on the sideline may be substantially different than baseline tests because of differences in shoe/cleat-type or surface, use of ankle tape or braces, or the presence of other lower extremity injury. ▸ Imaging is reserved for athletes where intracerebral bleeding is suspected. ▸ There is no same day RTP for an athlete diagnosed with a concussion. ▸ Athletes suspected or diagnosed with a concussion should be monitored for deteriorating physical or mental status. Neuropsychological testing: ▸ Neuropsychological (NP) tests are an objective measure of brain-behaviour relationships and are more sensitive for subtle cognitive impairment than clinical exam. ▸ Most concussions can be managed appropriately without the use of NP testing. ▸ Computerised neuropsychological (CNP) testing should be interpreted by healthcare professionals trained and familiar with the type of test and the individual test limitations, including a knowledgeable assessment of the reliable change index, baseline variability and false-positive and false-negative rates. ▸ Paper and pencil NP tests can be more comprehensive, test different domains and assess for other conditions which may masquerade as or complicate assessment of concussion. ▸ NP testing should be used only as part of a comprehensive concussion management strategy and should not be used in isolation. ▸ The ideal timing, frequency and type of NP testing have not been determined. ▸ In some cases, properly administered and interpreted NP testing provides an added value to assess cognitive function and recovery in the management of sports concussions. ▸ It is unknown if use of NP testing in the management of sports concussion helps prevent recurrent concussion, catastrophic injury or long-term complications. ▸ Comprehensive NP evaluation is helpful in the post-concussion management of athletes with persistent symptoms or complicated courses. Return to class: ▸ Students will require cognitive rest and may require academic accommodations such as reduced workload and extended time for tests while recovering from a concussion. Return to play: ▸ Concussion symptoms should be resolved before returning to exercise. ▸ A RTP progression involves a gradual, step-wise increase in physical demands, sports-specific activities and the risk for contact. ▸ If symptoms occur with activity, the progression should be halted and restarted at the preceding symptom-free step. ▸ RTP after concussion should occur only with medical clearance from a licenced healthcare provider trained in the evaluation and management of concussions. SHORT-TERM RISKS OF PREMATURE RTP: ▸ The primary concern with early RTP is decreased reaction time leading to an increased risk of a repeat concussion or other injury and prolongation of symptoms. LONG-TERM EFFECTS: ▸ There is an increasing concern that head impact exposure and recurrent concussions contribute to long-term neurological sequelae. ▸ Some studies have suggested an association between prior concussions and chronic cognitive dysfunction. Large-scale epidemiological studies are needed to more clearly define risk factors and causation of any long-term neurological impairment. Disqualification from sport: ▸ There are no evidence-based guidelines for disqualifying/retiring an athlete from a sport after a concussion. Each case should be carefully deliberated and an individualised approach to determining disqualification taken. Education: ▸ Greater efforts are needed to educate involved parties, including athletes, parents, coaches, officials, school administrators and healthcare providers to improve concussion recognition, management and prevention. ▸ Physicians should be prepared to provide counselling regarding potential long-term consequences of a concussion and recurrent concussions. Prevention: ▸ Primary prevention of some injuries may be possible with modification and enforcement of the rules and fair play. ▸ Helmets, both hard (football, lacrosse and hockey) and soft (soccer, rugby) are best suited to prevent impact injuries (fracture, bleeding, laceration, etc.) but have not been shown to reduce the incidence and severity of concussions. ▸ There is no current evidence that mouth guards can reduce the severity of or prevent concussions. ▸ Secondary prevention may be possible by appropriate RTP management. Legislation: ▸ Legislative efforts provide a uniform standard for scholastic and non-scholastic sports organisations regarding concussion safety and management. Future directions: ▸ Additional research is needed to validate current assessment tools, delineate the role of NP testing and improve identification of those at risk of prolonged post-concussive symptoms or other long-term complications. ▸ Evolving technologies for the diagnosis of concussion, such as newer neuroimaging techniques or biological markers, may provide new insights into the evaluation and management of sports concussion.
Background: Vestibular and ocular motor impairments and symptoms have been documented in patients with sport-related concussions. However, there is no current brief clinical screen to assess and monitor these issues. Purpose: To describe and provide initial data for the internal consistency and validity of a brief clinical screening tool for vestibular and ocular motor impairments and symptoms after sport-related concussions. Study design: Cross-sectional study; Level of evidence, 2. Methods: Sixty-four patients, aged 13.9 ± 2.5 years and seen approximately 5.5 ± 4.0 days after a sport-related concussion, and 78 controls were administered the Vestibular/Ocular Motor Screening (VOMS) assessment, which included 5 domains: (1) smooth pursuit, (2) horizontal and vertical saccades, (3) near point of convergence (NPC) distance, (4) horizontal vestibular ocular reflex (VOR), and (5) visual motion sensitivity (VMS). Participants were also administered the Post-Concussion Symptom Scale (PCSS). Results: Sixty-one percent of patients reported symptom provocation after at least 1 VOMS item. All VOMS items were positively correlated to the PCSS total symptom score. The VOR (odds ratio [OR], 3.89; P < .001) and VMS (OR, 3.37; P < .01) components of the VOMS were most predictive of being in the concussed group. An NPC distance ≥5 cm and any VOMS item symptom score ≥2 resulted in an increase in the probability of correctly identifying concussed patients of 38% and 50%, respectively. Receiver operating characteristic curves supported a model including the VOR, VMS, NPC distance, and ln(age) that resulted in a high predicted probability (area under the curve = 0.89) for identifying concussed patients. Conclusion: The VOMS demonstrated internal consistency as well as sensitivity in identifying patients with concussions. The current findings provide preliminary support for the utility of the VOMS as a brief vestibular/ocular motor screen after sport-related concussions. The VOMS may augment current assessment tools and may serve as a single component of a comprehensive approach to the assessment of concussions.
Objective: The Sports Concussion Assessment Tool 2 (SCAT2) and King-Devick (K-D) tests have both been proposed as sideline tools to detect sports-related concussion. We performed an exploratory analysis to determine the relation of SCAT2 components, particularly the Standardized Assessment of Concussion (SAC), to K-D test scores in a professional ice hockey team cohort during pre-season baseline testing. We also examined changes in scores for two athletes who developed concussion and had rinkside testing. Methods: A modified SCAT2 (no balance testing) and the K-D test, a brief measure of rapid number naming, were administered to 27 members of a professional ice hockey team during the 2011-2012 pre-season. Athletes with concussion also underwent rinkside testing. Results: Lower (worse) scores for the SCAT2 SAC Immediate Memory Score and the overall SAC score were associated with greater (worse) times required to complete the K-D test at baseline. On average, for every 1-point reduction in SAC Immediate Memory Score, we found a corresponding increase (worsening) of K-D time score of 7.3s (95% CI 4.9, 9.7, p<0.001, R(2)=0.62, linear regression, accounting for age). For the overall SAC score, 1-point reductions were associated with K-D score worsening of 2.2s (95% CI 0.6, 3.8, p=0.01, R(2)=0.25, linear regression). In two players tested rinkside immediately following concussion, K-D test scores worsened from baseline by 4.2 and 6.4s. These athletes had no differences found for SCAT2 SAC components, but reported symptoms of concussion. Conclusion: In this study of professional athletes, scores for the K-D test, a measure for which saccadic (fast) eye movements are required for the task of rapid number naming, were associated with reductions in Immediate Memory at a pre-season baseline. Both working memory and saccadic eye movements share closely related anatomical structures, including the dorsolateral prefrontal cortex (DLPFC). A composite of brief rapid sideline tests, including SAC and K-D (and balance testing for non-ice hockey sports), is likely to provide an effective clinical tool to assess the athlete with suspected concussion.
The purpose of this review is to examine the evidence for determining the lowest threshold for diagnosing a sport-related concussion. MEDLINE, CINAHL, EMBASE, Mosby's Index, PsycEXTRA, PsycINFO and Scopus. Key words included sports concussion, concussion assessment, diagnosis, concussion symptoms, onfield assessment and sports-related traumatic brain injury. The majority of concussions in sport occur without loss of consciousness or frank neurological signs. Some of the hallmark signs of acute concussion include mental confusion, memory and balance disturbance. Over the course of the first 24 h, the most common symptoms include headache, nausea, dizziness and balance problems, blurred vision or other visual disturbance, confusion, memory loss and 'fatigue'. Symptoms such as tiredness, irritability, nervousness or anxiety, sleep disturbance and sensitivity to light or noise may be noticed in the days after injury. The pathophysiology of sports concussion remains poorly understood. There appears to be a period of vulnerability following concussion in which an overlapping injury might cause magnified pathophysiology. Sport-related concussions can be difficult to diagnose. Concussion produces an evolving constellation of somatic, cognitive and neurobehavioral symptoms that are typically most severe during the earliest acute postinjury period (ie, within the first 24-48 h) and diminish over a matter of several days to weeks in the majority of athletes. Athletes suspected of concussion should be removed from play and evaluated thoroughly.