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Glucose effects on a continuous performance test of attention in adults
Abstract
Increases in plasma blood glucose levels modulate memory, mood, and, to some extent, attention in adults. Participants in the present study were administered glucose (10, 100, and 500 mg/kg, or 50 g) or placebo (23.7 mg saccharin) shortly prior to completing the test of variables of attention (TOVA), a continuous performance test (CPT) commonly used to assess attention for diagnostic purposes. There were significant increases in blood glucose levels for the 500 mg/kg and 50 g groups, but only the 100 mg/kg group showed significant changes in behavior in comparison to the saccharin group. Specifically, the 100 mg/kg group performed worse on measures of commission errors, post-commission responses, and post-commission response time variability. There were no differences among the groups on other major variables of attention, including omission errors, response time, and response time variability. The results of this study demonstrate that large doses of glucose which increase blood glucose levels do not influence attention, but that a moderate dose (100 mg/kg) selectively impairs measures of impulsivity or disinhibition. Practitioners and researchers should maintain an awareness of dietary effects on attention and continue to examine micronutrients as potential confounds on diagnostic tests of cognition and behavior.
... More errors occurred in the interference condition compared with the word-reading and color-naming conditions. In another study, Flint and Turek (2003) used the Test of Variable Attention (TOVA), a Continuous Performance task (CPT) for 21.6 minutes in non-diabetic college students. During the TOVA task, participants pressed a button every time a square with a hole near the top appeared and refrained from pressing a button when a square with a hole near the bottom appeared. ...
... Schächinger and colleagues (2003) reported that PASAT omission errors may have be due to participants' receiving inadequate glucose supplies such that they become so inattentive that they fail to notice stimuli, or are too overwhelmed to respond. Increased errors of commission (responding incorrectly) occurred on the CPT in participants at 100 mg/kg as compared to the saccharin group (Flint & Turek, 2003). Furthermore, impaired performance (on CRT and response selection) of healthy individuals remained, even after participants were restored to normal blood glucose levels at 85 mg/dl. ...
... Furthermore, impaired performance (on CRT and response selection) of healthy individuals remained, even after participants were restored to normal blood glucose levels at 85 mg/dl. Flint and Turek (2003) attribute errors of omission on the CPT task to inattention, and errors of commission to impulsivity, disinhibition, boredom, or fatigue. They suggest that 100 mg/kg of glucose is capable of producing increased commission errors. ...
... There is little evidence to support this proposition in the limited number of dose response studies that have been undertaken in healthy young samples. Flint and Turek [46] reported impaired attention performance after 100 mg/kg glucose drink. However, 500 mg/kg did not impair performance. ...
... The facilitative effect of glucose on sustained attention and vigilance has been demonstrated (e.g., [13,[25][26][27]55]), but not consistently [26,28,35,46]. However, there is little evidence to support the facilitative effects of glucose intake on the mood and motivation dimensions of mental energy. ...
This review examines the effects of carbohydrates, delivered individually and in combination with caffeine, on a range of cognitive domains and subjective mood. There is evidence for beneficial effects of glucose at a dose of 25 g on episodic memory, but exploration of dose effects has not been systematic and the effects on other cognitive domains is not known. Factors contributing to the differential sensitivity to glucose facilitation include age, task difficulty/demand, task domain, and glucoregulatory control. There is modest evidence to suggest modulating glycemic response may impact cognitive function. The evidence presented in this review identifies dose ranges of glucose and caffeine which improve cognition, but fails to find convincing consistent synergistic effects of combining caffeine and glucose. Whilst combining glucose and caffeine has been shown to facilitate cognitive performance and mood compared to placebo or glucose alone, the relative contribution of caffeine and glucose to the observed effects is difficult to ascertain, due to the paucity of studies that have appropriately compared the effects of these ingredients combined and in isolation. This review identifies a number of methodological challenges which need to be considered in the design of future hypothesis driven research in this area.
... Por otra parte, el control de la ejecución se puede realizar con pruebas de ejecución continua (Greenberg, 1996), con tareas de vigilancia (Servera y Cardo, 2006) o con escalas de observación (Conners, 1997;Miranda, García y Soriano, 2005;Swanson, 2003). Uno de los test más utilizadas para contrastar los niveles de activación cortical, según Flink y Turek (2003) o Rossiter (2004), es el TOVA de Greenberg (1996). ...
... El EEG Spectrum modifica los niveles de activación cortical con juegos interactivos que precisan, para su puesta en marcha y para su mantenimiento, de un nivel de activación programado en función de las posibilidades reales de cada sujeto. La eficacia de este tipo de intervención se suele contrastar habitualmente a través de pruebas de ejecución continua (Flink y Turek, 2003), tipo TOVA, pero en la práctica, parece mucho más operativo tener la posibilidad de valorar los cambios reales de activación que puede alcanzar cada sujeto entrenado, puesto que esta medida va a permitir comprobar, como afirman Lubar, White, Swartwood y Swartwood (1999), si es más o menos eficaz que el apoyo farmacológico. Como el entrenamiento con neurofeedback, según Lubar (1995), trata de disminuir la actividad theta (4-8 Hz) y aumentar la actividad beta (16-20Hz), es preciso controlar el cambio de ambas ondas de EEG a la vez. ...
Actualmente, no hay duda de que la atención sostenida se modifica con la práctica, de ahí que cada sujeto pueda generar un potencial atencional propio. También se sabe que este modelo dinámico de la atención está condicionado por variables cognitivas, conativas y afectivas que precisan de una evaluación y una intervención «adaptada». El trabajo cuasi-experimental que aquí se describe se enmarca dentro de esta perspectiva, siendo su objetivo conocer la eficacia de una intervención combinada (activación cortical y práctica continuada) para la disminución de los déficit en atención sostenida asociados a bajo rendimiento escolar. Se trabaja con una muestra de 64 sujetos con déficit en atención sostenida, con edades comprendidas entre los 10 y 16 años, de los cuales 30 forman el grupo control y 34 el grupo experimental. Los resultados obtenidos evidencian la eficacia de la intervención para la mejora de la atención sostenida (a mayor grado de activación aumenta la calidad de la concentración y el control de la ejecución). Estos resultados son discutidos, así mismo, tomando conciencia de algunas limitaciones metodológicas del estudio.
... Not all studies have found that glucose improves attention control (e.g., Flint & Turek, 2003;Manning, Hall, & Gold, 1990). One possible explanation for these seemingly contradictory findings is that glucose might benefit attention control primarily under difficult or demanding situations. ...
... The children were probably fatigued by the end of the day and perhaps wanted to go home, and therefore the task may have been especially difficult. Likewise, studies that used very demanding attention-control tasks (e.g., the Rapid Information Processing Task) have typically found that glucose improves performance (e.g., Benton et al., 1994), whereas studies that have used less demanding attention-control tasks (e.g., a task requiring that participants indicated when a square approached a target) have not found any benefit of glucose (e.g., Flint & Turek, 2003). As we noted above, increasing glucose among research participants who already have enough is not likely to yield discernible benefits, and the effects of glucose interventions will be best observed with difficult tasks and other measures that require effortful control by the self. ...
Past research indicates that self-control relies on some sort of limited energy source. This review suggests that blood glucose is one important part of the energy source of self-control. Acts of self-control deplete relatively large amounts of glucose. Self-control failures are more likely when glucose is low or cannot be mobilized effectively to the brain (i.e., when insulin is low or insensitive). Restoring glucose to a sufficient level typically improves self-control. Numerous self-control behaviors fit this pattern, including controlling attention, regulating emotions, quitting smoking, coping with stress, resisting impulsivity, and refraining from criminal and aggressive behavior. Alcohol reduces glucose throughout the brain and body and likewise impairs many forms of self-control. Furthermore, self-control failure is most likely during times of the day when glucose is used least effectively. Self-control thus appears highly susceptible to glucose. Self-control benefits numerous social and interpersonal processes. Glucose might therefore be related to a broad range of social behavior.
... Social competence is negatively affected by impulsivity traits, and impulse control may be metabolically expensive process, creating higher glucose demand (Gailliot and Baumeister, 2007). Low blood glucose levels are indeed associated with impulsive aggression (DeWall et al., 2011); administration of glucose can reduce aggression in response to provocation among people high in trait aggression (Denson et al., 2010) and reduce disinhibition in a continuous performance test (Flint and Turek, 2003), whereas behavioural flexibility depends on glucoregulation (Riby et al., 2017). ...
Rewards are rewarding owing to their hedonic or metabolic value. Individual differences in sensitivity to rewards are predictive of mental health problems but may reflect variation in metabolic types. We have assessed the association of two distinguishable aspects of reward sensitivity, openness to rewards (the striving towards multiple rewards) and insatiability by reward (the strong pursuit and fixation to a particular reward), with measures of metabolism and activity in a longitudinal study of representative birth cohort samples. We used data of the Estonian Children Personality Behaviour and Health Study (original n = 1238) collected at age 15, 18 and 25. Reward sensitivity and physical activity were self-reported during a laboratory visit, when also blood sampling, measurement of blood pressure, height and weight, aerobic exercise testing and the diet interview, after the participants had kept food diary, took place. In the younger cohort, physical activity was also assessed by accelerometry at age 18 and 25. Across adolescence and young adulthood, openness to rewards was positively associated with physical activity and negatively with blood pressure and serum levels of glucose, insulin and cholesterol levels. In contrast, insatiability by reward was positively associated with serum triglyceride levels and negatively with energy intake and cardiorespiratory fitness. In conclusion, the two facets of reward sensitivity have a fairly different association with a variety of metabolic and health-related measures. This may explain the variable findings in literature, and suggests that individual differences in reward sensitivity are part of a complex physiological variability, including energy expenditure profiles.
... Sunram-Lea et al. [106] found a positive correlation between BGL and a number of memory performance measures which were not present when only the glucose condition was analysed, suggesting that 25 g glucose consumption may have breached the upper threshold of optimal BGL in this young adult sample. Four studies found no association between AUC or changes in BGL with cognitive performance [63,80,104,107]. These studies analysed changes in BGL over 30-53 min, which may not have been long enough to identify significant changes in BGL. ...
A relationship between excessive sugar consumption and cognitive function has been described in animal models, but the specific effects of sugars in humans remains unclear. This systematic review and meta-analysis aimed to evaluate the current knowledge, research characteristics, and quality of evidence of studies investigating the impacts of free and added sugars on human cognition in healthy participants. The review identified 77 studies (65 experimental trials, n = 3831; 9 cross-sectional studies, n = 11,456; and 3 cohort studies, n = 2059). All cohort studies and eight of the nine cross-sectional studies found significant positive correlations between added sugar consumption and risk of cognitive impairment. Four studies identified reduced risk of cognitive impairment associated with natural fructose-containing foods. The majority of randomised control trials assessed short-term glucose facilitation effects on cognitive outcomes. The results from these studies suggest the need for a tightly regulated blood glucose level, dependent on individualised physiological factors, for optimal cognitive function. A meta-analysis of a subset of studies that assessed the impact of glucose on recall found improvements in immediate free recall compared to controls (p = 0.002). The findings highlight the potentially detrimental effect of excessive, long-term, or prenatal added sugar consumption on cognitive function. Further research is needed to examine the specific effects of free and added sugars on cognitive function.
... The outcomes of the 18 studies in which glucose and/or insulin responses were measured for time periods < 120 min postprandially are mostly consistent with the results of our metaanalyses. Most studies reported no effects (67,(69)(70)(71)(72)(73)(74)(75)(76)(77)(78)83) or very small changes (70,74,76) in PPG and PPI responses after LES ingestion. ...
Background:
It has been suggested that low-energy sweeteners (LES) may be associated with an increased risk of metabolic diseases, possibly due to stimulation of glucose-responsive mechanisms.
Objective:
We conducted a systematic review and meta-analysis of human intervention studies examining the acute effect of LES intake on postprandial glucose (PPG) and postprandial insulin (PPI) responses, in order to comprehensively and objectively quantify these relations.
Methods:
We systematically searched the Medline, OVID FSTA, and SCOPUS databases until January 2020. Randomized controlled trials comparing acute postprandial effects on PPG and/or PPI after exposure to LES, either alone, with a meal, or with other nutrient-containing preloads to the same intervention without LES were eligible for inclusion. PPG and PPI responses were calculated as mean incremental area under the curve divided by time. Meta-analyses were performed using random effects models with inverse variance weighing.
Results:
Twenty-six papers (34 PPG trials and 29 PPI trials) were included. There were no reports of statistically significant differences in the effects of LES on PPG and PPI responses compared with control interventions. Pooled effects of LES intake on the mean change difference in PPG and PPI were -0.02 mmol/L (95% CI: -0.09, 0.05) and -2.39 pmol/L (95% CI: -11.83, 7.05), respectively. The results did not appreciably differ by the type or dose of LES consumed, cointervention type, or fasting glucose and insulin levels. Among patients with type 2 diabetes, the mean change difference indicated a smaller PPG response after exposure to LES compared with the control (-0.3 mmol/L; 95% CI: -0.53, -0.07).
Conclusions:
Ingestion of LES, administered alone or in combination with a nutrient-containing preload, has no acute effects on the mean change in postprandial glycemic or insulinemic responses compared with a control intervention. Apart from a small beneficial effect on PPG (-0.3 mmol/L) in studies enrolling patients with type 2 diabetes, the effects did not differ by type or dose of LES, or fasting glucose or insulin levels. This review and meta-analysis was registered at PROSPERO as CRD42018099608.
... A recent meta-analysis of 29 acute RCTs [50,65,67,79,83,93,96,98,[101][102][103][105][106][107][108][109][110][111][112][113][114][115][116][117][118][119][120][121][122] of 741 subjects examined by Nichol et al. [123••] showed that intakes of aspartame, sucralose, saccharine and steviosides consumed without glucose or other calories did not alter blood glucose levels compared with baseline. No differences in glycaemic effects by type of NNS were observed. ...
Purpose of Review
The consumption of foods and beverages containing non-nutritive sweeteners (NNS) has increased worldwide over the last three decades. Consumers’ choice of NNS rather than sugar or other nutritive sweeteners may be attributable to their potential to reduce weight gain.
Recent Findings
It is not clear what the effects of NNS consumption are on glycaemic control and the incidence of type 2 diabetes. This review aims to examine this question in epidemiological, human intervention and animal studies.
Summary
It is not clear that NNS consumption has an effect on the incidence of type 2 diabetes or on glycaemic control even though there is some evidence for the modification of the microbiome and for interaction with sweet taste receptors in the oral cavity and the intestines’ modification of secretion of glucagon-like peptide-1 (GLP-1), peptide YY (PYY), ghrelin and glucose-dependent insulinotropic polypeptide (GIP), which may affect glycaemia following consumption of NNS. In conclusion, long-term studies of NNS consumption are required to draw a firm conclusion about the role of NNS consumption on glycaemic control.
... However, performance during some cognitive tasks (such as working memory and attention) may be impacted more than others (Lamport et al. 2009). Glucose has also been shown to have memory enhancing effects that are dose dependent, with small and large (e.g., 10 and 500 mg/kg, respectively) doses showing little effect but moderate (e.g., 100 mg/kg) doses providing memory enhancement (Flint and Turek 2003;Smith et al. 2011). Whether glucose levels influence cognitive function (such as executive function and behavioral flexibility-as measured through a complement of behavioral responses, for instance extinction, inhibition, and reversal learning) is also not well understood ( Riby et al. 2017). ...
Inhibitory control is a term used to envelop a collection of processes that allow an organism to refrain from engaging in an inappropriate prepotent or responsive behavior. Studies have examined the propensity of inhibitory control by nonhuman animals, from the cognitively complex processes involved in self-control to potentially less cognitively taxing processes such as motoric self-regulation. Focusing on canines, research has suggested that the domestication process as well as experiences during ontogeny contribute to inhibitory control. Diet may also play an important role in an individual’s ability to self-regulate. This study examined this possibility by investigating motoric self-regulation in sled dogs, using three well-established tasks (i.e., A-not-B Bucket, Cylinder, and A-not-B Barrier tasks), performed after consumption of one of three dietary treatments with different glycemic index values. We also compared the performance of sled dogs during these tasks with results previously obtained from pet dogs. Overall, the results show many similarities in the performance of sled dogs and pet dogs on the motoric self-regulation tasks, with the notable exception that sled dogs may have a stronger spatial perseveration during the A-not-B Bucket task. Previous research findings reporting a lack of correlation among these tasks are also supported. Finally, during the early postprandial phase (period after consumption), dietary treatments with different glycemic index values did not influence self-regulatory performance for sled dogs.
... 20% or lower. In contrast, merely five studies [22,26,44,46,47] provided a sample size justification. ...
Background/objectives:
Nonnutritive sweeteners (NNSs) are zero- or low-calorie alternatives to nutritive sweeteners, such as table sugars. A systematic review and meta-analysis of randomized controlled trials was conducted to quantitatively synthesize existing scientific evidence on the glycemic impact of NNSs.
Subjects/methods:
PubMed and Web of Science databases were searched. Two authors screened the titles and abstracts of candidate publications. The third author was consulted to resolve discrepancies. Twenty-nine randomized controlled trials, with a total of 741 participants, were included and their quality assessed. NNSs under examination included aspartame, saccharin, steviosides, and sucralose. The review followed the PRISMA guidelines.
Results:
Meta-analysis was performed to estimate and track the trajectory of blood glucose concentrations over time after NNS consumption, and to test differential effects by type of NNS and participants' age, weight, and disease status. In comparison with the baseline, NNS consumption was not found to increase blood glucose level, and its concentration gradually declined over the course of observation following NNS consumption. The glycemic impact of NNS consumption did not differ by type of NNS but to some extent varied by participants' age, body weight, and diabetic status.
Conclusions:
NNS consumption was not found to elevate blood glucose level. Future studies are warranted to assess the health implications of frequent and chronic NNS consumption and elucidate the underlying biological mechanisms.
... Indeed, laboratory depletion of glucose resources using taxing mental exertion tasks results in limited performance (Martijn et al., 2002). Other research provides evidence for selective impairments in attentional performance due to blood glucose levels such that attentional performance was not affected by higher levels of glucose but was improved with moderate levels of glucose (Flint & Turek, 2003). However, Molden and colleagues (2012) found that simply rinsing the mouth with a glucose solution also increased self-control. ...
Self-control is an important aspect of human daily functioning. Humans must choose how to respond in stressful or emotional situations while simultaneously trying to limit poor decision making. Effective selfcontrol bolsters the ability to delay gratification, regulate social behaviors, mitigate mistakes, and make decisions. However, many variables can affect the human ability to utilize these attributes. In recent years, a number of studies have started to focus on self-control in humans and on how humans use or deplete self-control resources. One area that is not yet well-understood is the impact of sleep habits on self-control and, more generally, on physiological and cognitive resources that may impact self-control. It is increasingly clear; however, that sleep impacts daily functioning and behaviors. Many researchers now view self-control as a finite resource that not only affects daily behaviors and choices but also is affected in turn by these behaviors and choices. Poor sleep and sleepdeprivation could be part of this feedback loop and may negatively impact these resources for self-control in three ways: (1) Sleep-deprived individuals, simply by being awake more hours, could be expected to expend more self-control. (2) The lack of sleep could create a physiological load that could deplete self-control resources. (3) Poor sleep or the lack of sleep could negatively affect the resources for selfcontrol if those resources are reset or replenished during normal sleep.
... However, the authors warned of the need for longitudinal studies to determine the directionality of the relationship between high blood glucose and impulsivity. Flint and Turek (2003) assessed 67 subjects, 18-50 years in age, through a SART similar to the Go/No-Go task, after offering them 10, 100, or 500mg/kg, or 50g of glucose, or placebo. Moderate doses of 100mg/kg of glucose correlated with indicators of impulsivity and disinhibition (commission errors). ...
Aims:
The objectives were to use inexpensive and easy-to-apply tasks in order to investigate the differences between type 1 diabetes mellitus (T1DM) patients and controls regarding attention and impulsivity, which are the basis for key-executive function components that are traditionally assessed using subjective, long and difficult to reproduce questionnaires. Additionally, we sought to correlate these differences with clinical characteristics, and to explore correlations between the tasks.
Methods:
We compared the scores of 20 T1DM patients with 20 controls. The sample population included both males and females, aged 12-15 years. They were tested using a Go/No-Go paradigm and a Maze task, and correlations were verified between the groups.
Results:
The T1DM group had more anticipatory answers (AA) in the Go/No-Go task (p <0.05), and made more direction changes in Mazes (p<0.01). There was a correlation between non-severe hypoglycemia and AA (p=0.01), as well as between severe hypoglycemia and the number of touches in Mazes' walls (p<0.05). Glycated hemoglobin (HbA1c)>9% correlated with a greater number of alleys in Mazes (p<0.05). The tasks' parameters were coherent among each test, and also between them.
Conclusions:
We found indicators of inattention and impulsivity to be associated with T1DM, with inattention being closely related with hyperglycemia, and impulsivity being associated with hypoglycemia. Further research is needed to study diabetes-associated cognitive decline with more objective parameters, and to analyse the reliability and psychometric properties of the tasks proposed in this study.
... Another version of this type of test is the Bakan test, in which subjects view a computer screen presenting digits, one at a time, and are asked to press a key upon seeing 3 consecutive even or 3 consecutive odd digits. Whereas 5 studies that examined vigilance demonstrated no significant effects (15,(20)(21)(22)(23), 3 exhibited better performance after breakfast than after nobreakfast (24)(25)(26) conditions. No test emerged as best able to detect differences, and methodologic variability in study designs precludes pattern detection for these disparate findings. ...
Extensive literature has addressed the acute cognitive effects of breaking a fast. Recent reviews in this line of work have synthesized available research on the cognitive consequences of fasting compared with nutrient intake and the cognitive effects of macronutrient consumption. These largely have been inconclusive, possibly in part because of selection criteria limiting the scope of studies covered. The purpose of the current review is to integrate the results of the literature examining the cognitive effects of breakfast and breakfast composition in adults with the use of a flexible definition of breakfast, specifically, any caloric intake after a fasting period of ≥8 h. This review includes 38 studies that examine the acute cognitive impact of breakfast and 16 studies that examine the effects of breakfast composition. Results suggest that healthy adults show a small but robust advantage for memory (particularly delayed recall) fromconsuming breakfast. Largely equivocal results emerge for attention and motor and executive function; there were no effects from breakfast on language. Regarding breakfast composition, a smaller number of studies and widely disparate methodology addressing this question preclude definitive conclusions about the effects of cognition. A subset of this literature examines these questions in the context of glucoregulation; the findings emphasize the importance of considering differences in glucoregulation in research designs, even among healthy cohorts. The limitations of this literature includemethodologic differences, such as the use of different tests to measure cognitive constructs, as well as the effects of timing in test administration.
... Individuals with low inhibition are at risk for poor glycemic control leading to enhanced inhibition difficulties (Duke & Harris, 2014;Gailliot et al., 2007). Indeed, high blood glucose levels are associated with decreased inhibition (Flint & Turek, 2003). Furthermore, diabetes management is often associated with anxiety provoking behaviors (e.g., daily insulin self-injections, finger-pricks, social interactions) that are imperative to achieving optimal diabetes control (Snoek & Skinner, 2006). ...
Individuals who perform poorly on measures of the executive function of inhibition have higher anxious arousal in comparison to those with better performance. High anxious arousal is associated with a pro-inflammatory response. Chronically high anxious arousal and inflammation increase one’s risk of developing type 2 diabetes. We sought to evaluate anxious arousal and inflammation as underlying mechanisms linking inhibition with diabetes incidence. Participants (N = 835) completed measures of cognitive abilities, a self-report measure of anxious arousal, and donated blood to assess interleukin-6 (IL-6) and glycated hemoglobin (HbA1c). Individuals with low inhibition were more likely to have diabetes than those with high inhibition due to the serial pathway from high anxious arousal to IL-6. Findings remained when entering other indicators of cognitive abilities as covariates, suggesting that inhibition is a unique cognitive ability associated with diabetes incidence. On the basis of our results, we propose several avenues to explore for improved prevention and treatment efforts for type 2 diabetes.
... Otra hipótesis acerca de la función cognitiva relacionada al desempeño de una CPT es el posible rol de las funciones motoras relacionadas (Epstein, Johnson, Varia y Conners, 2001;Fallgatter, 2001;Flint y Turek. 2003;Goldberg y Weinberger, 1995;Ornitz, Gehricke, Russell, Pynoos y Siddarth, 2001; van den Bosch, Rombouts y van Asma, 1996), argumentando esto sobre la base de que la atención empleada en las CPT pueden reflejar un proceso de preparación de la respuesta más que una vigilancia efectiva. ...
Attention processes are essential for optimal athletic performance, particularly in combat sports. Previous studies of task-related event-related potentials (ERPs) in athletes have reported differences in amplitudes and latencies when expert athletes were compared with less expert or non-athletes. The aim of the present study was to identify differences in performance and ERPs between skilled and novice martial arts athletes during sustained attention, transient attention and motor inhibition tasks. ERPs from 21 martial arts athletes were obtained while they performed a Continuous Performance Task (CPT), a cued Continuous Performance Task (c-CPT) and Stop task. In the CPT task, skilled athletes showed larger amplitudes in the P100 and P200 components and smaller amplitudes in the N200 component in response to targets, than novices. The opposite effects were observed in the c-CPT task, in which novices showed larger amplitudes in the P100, P200, P300 and late positive components on the “go trials” than skilled athletes and smaller amplitudes in
contingent negative variation (CNV). We propose that larger amplitudes in skilled athletes during CPT are likely related to earlier identification, evaluation and perception of the stimulus in skilled athletes compared with novices. Smaller amplitudes in positive components and larger amplitude in CNV, in skilled athletes during c-CPT could indicate that the cue stimulus produced greater facilitation in this group, thereby allowing the skilled athletes to respond automatically using fewer attention resources. In conclusion, sport expertise enhances control during sustained attention task and improves efficiency in automatic processing tasks.
... Several studies have reported evidence consistent with glucose producing a short-term increase in the efficient use of limited attentional resources (Benton et al. 1987(Benton et al. , 1994Flint and Turek 2003;Fucetola et al. 1999;Rao et al. 2005;Riby et al. 2008;Scholey et al. 2009;Serra-Grabulosa et al. 2010) and, given participants were explicitly required to remember object-location pairings, this could be one possible mechanism for improved binding. Specifically, our task requires the maintenance of multiple object-location pairs and participants may have strategically attended to a subset of these pairs by prioritizing resources. ...
Rationale
There is evidence that glucose temporarily enhances cognition and that processes dependent on the hippocampus may be particularly sensitive. As the hippocampus plays a key role in binding processes, we examined the influence of glucose on memory for object-location bindings.
Objective
This study aims to study how glucose modifies performance on an object-location memory task, a task that draws heavily on hippocampal function.
Methods
Thirty-one participants received 30 g glucose or placebo in a single 1-h session. After seeing between 3 and 10 objects (words or shapes) at different locations in a 9 × 9 matrix, participants attempted to immediately reproduce the display on a blank 9 × 9 matrix. Blood glucose was measured before drink ingestion, mid-way through the session, and at the end of the session.
Results
Glucose significantly improves object-location binding (d = 1.08) and location memory (d = 0.83), but not object memory (d = 0.51). Increasing working memory load impairs object memory and object-location binding, and word-location binding is more successful than shape-location binding, but the glucose improvement is robust across all difficulty manipulations. Within the glucose group, higher levels of circulating glucose are correlated with better binding memory and remembering the locations of successfully recalled objects.
Conclusions
The glucose improvements identified are consistent with a facilitative impact on hippocampal function. The findings are discussed in the context of the relationship between cognitive processes, hippocampal function, and the implications for glucose’s mode of action.
... Most research on ego depletion has focused on glucose as the primary resource for these internal reserves such that when blood glucose levels are low; glucose is conserved resulting in poorer self-control (Hagger et al., 2010). Other research provides evidence for selective impairments in attentional performance due to blood glucose levels such that attentional performance was not affected by higher levels of glucose but was improved with moderate levels of glucose (Flint and Turek, 2003). However, Molden et al. (2012) found that simply rinsing the mouth with a glucose solution also increased self-control. ...
Good sleep habits and effective self-control are important components of successful functioning. Unfortunately chronic sleep loss and impaired self-control are common occurrences for many individuals which can lead to difficulty with daily self-control issues such as resisting impulses and maintaining attentive behavior. Understanding how self-control is depleted and how good sleep habits may help replenish and maintain the capacity for self-control is an important issue. A sleep-deprived individual who has expended the necessary resources for self-control is at an increased risk for succumbing to impulsive desires, poor attentional capacity, and compromised decision making. To date, few studies have investigated how sleep and self-control are inter-related. The goal of this mini-review is to explore the intersection between sleep habits and self-control and encourage researchers to focus on a new area of research that integrates what are at present largely separate areas in psychology and human neurosciences.
... Participants who heard the lure list also had greater recall of the lure word 'chair' in comparison to participants who heard the control list. Together, these results replicate what has been reported in other studies using 50 g of d-glucose (Flint & Turek, 2003;Mohanty & Flint, 2001) and the DRM task (Roediger & McDermott, 1995). However, d-glucose also appeared to selectively impair performance on the recognition test, but had no effect during the recall test. ...
Glucose, a well-known memory modulator and physiological component of acute arousal, was examined for its influence on the false memory effect in two experiments. A baseline blood glucose (BG) measure was followed by the consumption of d-glucose or saccharin and a 15-minute post-consumption BG test in Experiment 1. Participants were then asked to listen to either a false memory lure wordlist or a control wordlist. Subsequently, participants completed recall and recognition tests. In Experiment 2, participants consumed either glucose or saccharin prior to listening to ten lure wordlists, each followed by a recall and recognition test. Results of Experiment 1 revealed significant elevations in BG following d-glucose consumption and greater recall for lure lists than control lists regardless of drink type. The lure was also recalled significantly more often from the lure list, replicating the false memory effect for words using a single wordlist. D-glucose had no effect on word recall, but decreased wordlist recognition performance, and had no effect on false memory or 'remember'/'know' judgments. Results of Experiment 2 indicated that d-glucose significantly enhanced word recall and recognition of old words, but as in Experiment 1, it did not alter recall of the lure, thus failing to influence the false memory effect. The failure of glucose to alter the false memory effect suggests that this neurobiological product of the stress cascade may not likely alter real world occurrences of false memory.
... Benton et al. 1995; Heseker et al. 1995). A recent dose-ranging study of 67 adult students (Flint and Turek 2003) with normal glucose metabolism suggests that large doses of glucose that increase blood glucose levels do not influence attention, but that a moderate dose (100 mg/kg) of glucose selectively impairs measures of impulsivity or disinhibition. Furthermore, the glycaemic index (broadly how quickly the carbohydrate can be utilized) of carbohydrate sources also appears to influence cognitive effects in human and animal studies (Benton et al. 2003). ...
This chapter explores the potential beneficial effects of good nutrition on a person's behaviour and well-being. The opening section recounts anthropological studies establishing the link between nutrition and the evolution of the human brain. The differences between the diet of our ancestors and modern-day food are identified, coupled with developments in food production and acquisition leading to issues such as dietary complacency and food inequality. A combination of these factors has been linked to specific health risks. Dietary standards have traditionally been geared towards health issues excluding behavioural well-being, and a section is devoted to assessing its impact on brain function and activity. The detrimental effect of changes in the modern diet on a person's behavioural well-being is tackled, beginning with references to psychological disorders such as depression and schizophrenia, to childhood developmental disorders, and even anti-social behaviour. The chapter concludes with the global implications of nutrition on well-being.
... 48,49,53,54,[57][58][59][62][63][64][65][66][67][68][69][70][71]73,[75][76][77][78] However, additional studies report that glucose does not enhance certain aspects of memory (recall, visual, short-and long-term memory). 48,[50][51][52][55][56][57][58][60][61][62]71,74,75 Discrepancies in the reported findings may derive from the age of the subjects (young versus elderly), the type of memory tested (declarative versus short-term memory), testing instrument, glucose dose, time of testing, and duration of treatment. The available studies lack consistency in the type of memory-testing instrument used. ...
The numbers of marketing claims and food, beverage, and drug products claiming to increase mental energy have risen rapidly, thus increasing the need for scientific specificity in marketing and food label claims. Mental energy is a three-dimensional construct consisting of mood (transient feelings about the presence of fatigue or energy), motivation (determination and enthusiasm), and cognition (sustained attention and vigilance). The present review focuses on four dietary constituents/supplements (Ginkgo biloba, ginseng, glucose, and omega-3 polyunsaturated fatty acids) to illustrate the current state of the literature on dietary constituents and mental energy. The strongest evidence suggests effects of Ginkgo biloba on certain aspects of mood and on attention in healthy subjects, as well as associations between omega-3 polyunsaturated fatty acids and reduced risk of age-related cognitive decline. Limitations of the current data and challenges for future research are discussed.
... El EEG Spectrum modifica los niveles de activación cortical con juegos interactivos que precisan, para su puesta en marcha y para su mantenimiento, de un nivel de activación programado en función de las posibilidades reales de cada sujeto. La eficacia de este tipo de intervención se suele contrastar habitualmente a través de pruebas de ejecución continua (Flink y Turek, 2003), tipo TOVA, pero en la práctica, parece mucho más operativo tener la posibilidad de valorar los cambios reales de activación que puede alcanzar cada sujeto entrenado, puesto que esta medida va a permitir comprobar, como afirman Lubar, White, Swartwood y Swartwood (1999), si es más o menos eficaz que el apoyo farmacológico. Como el entrenamiento con neurofeedback, según Lubar (1995), trata de disminuir la actividad theta (4-8 Hz) y aumentar la actividad beta (16- 20Hz), es preciso controlar el cambio de ambas ondas de EEG a la vez. ...
... The TOVA has been used with children to assess for Attention Deficit Hyperactivity Disorder (ADHD) (Forbes, 1998). In adult samples, the TOVA has been used to assess the effect of substances on inattention and impulsivity (Flint and Turek, 2003). Studies of ADHD suggest the TOVA has adequate reliability (Llorente et al., 2007) and validity (Forbes, 1998). ...
The purpose of this study was to examine the role of the serotonin (5-HT) system in alcohol-related aggression.
Specifically, we experimentally examined the effects of 5-HT augmentation on alcohol-related aggression in men (n = 56). After consuming either alcohol (mean blood alcohol concentration of 0.10%) or a placebo (no alcohol) drink, and taking either 20 mg of paroxetine (Paxil) or a placebo pill, participants were provided the opportunity to administer electric shock to a (faux) opponent during a task disguised as a reaction-time game. Aggression was defined as the intensity of shock chosen and the frequency with which an extreme (clearly painful) shock was chosen. We predicted that 5-HT augmentation would be associated with lower aggressive behavior overall, and also reduce the aggression facilitating effects of acute alcohol intoxication.
The results indicated that alcohol intoxication increased aggression, particularly under low provocation. Paroxetine decreased aggression, particularly during high provocation. These effects, however, occurred independently of each other.
The effect of alcohol on extreme aggression was moderated by previous aggression history, with more aggressive individuals showing greater alcohol-related increases in extreme aggression.
... Other hypotheses about the cognitive function underlying CPT performance point to the possible role of motor related functions (Epstein, Johnson, Varia & Conners, 2001;Fallgatter, 2001: Flint & Turek. 2003Goldberg & Weinberger, 1995;Ornitz, Gehricke, Russell, Pynoos & Siddarth, 2001;van den Bosch, Rombouts & van Asma, 1996). Goldberg & Weinberger (1995) concluded on the basis of many arguments, that "attention as deployed in the CPT may reflect response readiness rather than actual vigilance". ...
One of the most frequently applied methods to study abnormal cognition is the Continuous Performance Task (CPT). It is unclear, however, which cognitive functions are engaged in normal CPT performance. The aims of the present study were to identify the neurocognitive functions engaged in the main variants of the CPT and to determine to what extent these variants differentially engage these functions. We hypothesized that the main CPT versions (CPT-X, CPT-AX, CPT-Identical Pairs) can be distinguished by whether they demand sustained or transient attention and sustained or transient response preparation. Transient attention to objects like letters or digits, that is, the need to switch attention to different objects from trial to trial, impairs target detection accuracy relative to sustained attention to a single object. Transient response preparation, that is, the possibility to switch response preparation on and off from trial to trial, improves response speed relative to having to sustain response preparation across all trials. Comparison of task performance and Event-Related brain Potentials (ERPs) of healthy participants obtained in the main CPT variants confirmed these hypotheses. Behavioral and ERP measures indicated worse target detection in the CPT-AX than in the CPT-X, consistent with a higher demand on transient attention in that task. In contrast, behavioral and ERP measures indicated higher response speed in the CPT-AX than in the CPT-X, associated with more response preparation in advance of the targets. This supports the idea of increased transient response preparation in the CPT-AX. We conclude that CPTs differ along at least two task variables that each influences a different cognitive function.
... Before test 2 of the EUH-CES trials, the subjects`S gluc was 90 mgIdL j1 (5 mM), which is lower than that of the studies showing that glucose administration improves cognitive performance (Q 6 mM). However, S gluc does not explain the discrepancy between studies; Flint and Turek (9) found no differences in most aspects of TOVA performance (including omission errors, response time, or sensitivity) between a saccharin control group and the groups that consumed a 10-, 100-, or 500-mgIkg j1 or 50-g dose of glucose before testing. In that study, S gluc varied from approximately 80 mgIdL j1 (saccharin) to approximately 115 mgIdL j1 (50-g dose). ...
To determine the effects of dehydration (DEH) on attentional vigilance in male basketball players.
The Test of Variables of Attention (TOVA; Universal Attention Disorders) was administered to 11 male basketball players (17-28 yr) at baseline (test 1), after walking (50% V O2max) in the heat (40 degrees C and 20% relative humidity) (test 2), and then after a simulated basketball game (test 3). Tests 2 and 3 were performed while subjects were either DEH (1-4%) or euhydrated (EUH). The TOVA consisted of target-infrequent and target-frequent conditions, simulating static and dynamic (such as a basketball game) environments, respectively. TOVA measures included errors of omission (OE) and commission (CE), response time (RT), and sensitivity.
During the target-infrequent half of test 3, EUH resulted in significantly better sensitivity (+0.4+/-1.2 vs -0.9+/-1.3), faster RT (-8+/-20 vs +16+/-28), and fewer OE (-0.4+/-0.7 vs +1.3+/-2.4) compared with DEH. During the target-frequent half, EUH resulted in significantly fewer OE (-4+/-15 vs +5+/-7) and CE (-1.9+/-3.2 vs 0.6+/-1.4) in test 2 and greater sensitivity (+0.7+/-2.6 vs -0.7+/-1.1) and faster RT (-21+/-28 vs +5+/-31) than DEH in test 3.
Vigilance-related attention of male basketball players was impaired by DEH, especially during the target-frequent condition of the TOVA. These results suggest that fluid replacement is essential to prevent the decline in vigilance that occurs with DEH in highly dynamic environments. Therefore, basketball players should be advised to maintain EUH for optimal concentration and attentional skills during competition.
... A further CPT used was the test of variables of attention (TOVA), where stimuli are geometric squares. Flint and Turek (2003) report a negative effect of a 100 mg/kg glucose dose on TOVA performance compared with placebo, such that this moderate glucose dose impaired measures of impulsivity and disinhibition. ...
The potential for foods to exert effects on behaviour is increasingly recognised. Previous studies have incorporated both well-known and lesser-known cognitive tests in the evaluation of relationships between macronutrient interventions and mental performance. Systematic review methodology was used to identify studies of macronutrient effects on cognition, limited to acute effects in young, fasted, healthy adults. Thirty-one studies met the inclusion criteria, yielding a total of 134 outcome measures. The studies reviewed displayed a predominance of soluble glucose manipulations, and a paucity of complex carbohydrate, protein or fat manipulations. Memory performance was most commonly measured, but verbal fluency, attention, reaction time, psychomotor skill and problem solving were also assessed. Significant differences in performance tended to occur under circumstances of more intense cognitive demand and after delays. Memory emerged as the most sensitive cognitive modality to macronutrient manipulations. Tasks identified as sensitive included Serial Sevens, Free Word Recall and Cued Word Recall, with tentative support for the Word Recognition Task. Findings also suggested that visuo-spatial memory may be influenced by macronutrient manipulations.
This opinion deals with the re‐evaluation of saccharin and its sodium, potassium and calcium salts (E 954) as food additives. Saccharin is the chemically manufactured compound 1,2‐benzisothiazol‐3(2H)‐one‐1,1‐dioxide. Along with its sodium (Na), potassium (K) and calcium (Ca) salts, they are authorised as sweeteners (E 954). E 954 can be produced by two manufacturing methods i.e. Remsen‐Fahlberg and Maumee. No analytical data on potential impurities were provided for products manufactured with the Maumee process; therefore, the Panel could only evaluate saccharins (E 954) manufactured with the Remsen‐Fahlberg process. The Panel concluded that the newly available studies do not raise a concern for genotoxicity of E 954 and the saccharins impurities associated with the Remsen‐Fahlberg manufacturing process. For the potential impurities associated with the Maumee process, a concern for genotoxicity was identified. The data set evaluated consisted of animals and human studies. The Panel considered appropriate to set a numerical acceptable daily intake (ADI) and considered the decrease in body weight in animal studies as the relevant endpoint for the derivation of a reference point. An ADI of 9 mg/kg body weight (bw) per day, expressed as free imide, was derived for saccharins (E 954). This ADI replaces the ADI of 5 mg /kg bw per day (expressed as sodium saccharin, corresponding to 3.8 mg /kg bw per day saccharin as free imide) established by the Scientific Committee on Food. The Panel considered the refined brand‐loyal exposure assessment scenario the most appropriate exposure scenario for the risk assessment. The Panel noted that the P95 exposure estimates for chronic exposure to saccharins (E 954) were below the ADI. The Panel recommended the European Commission to consider the revision of the EU specifications of saccharin and its sodium, potassium and calcium salts (E 954).
The importance of nutrition in human health has been understood for over a century. However, debate is ongoing regarding the role of added and free sugars in physiological and neurological health. In this narrative review, we have addressed several key issues around this debate and the major health conditions previously associated with sugar. We aim to determine the current evidence regarding the role of free sugars in human health, specifically obesity, diabetes, cardiovascular diseases, cognition, and mood. We also present some predominant theories on mechanisms of action. The findings suggest a negative effect of excessive added sugar consumption on human health and wellbeing. Specific class and source of carbohydrate appears to greatly influence the impact of these macronutrients on health. Further research into individual effects of carbohydrate forms in diverse populations is needed to understand the complex relationship between sugar and health.
Everybody eats, and what we eat – or do not – affects the brain and mind. There is significant general, applied, academic, and industry interest about nutrition and the brain, yet there is much misinformation and no single reliable guide. Diet Impacts on Brain and Mind provides a comprehensive account of this emerging multi-disciplinary science, exploring the acute and chronic impacts of human diet on the brain and mind. It has a primarily human focus and is broad in scope, covering wide-ranging topics like brain development, whole diets, specific nutrients, research methodology, and food as a drug. It is written in an accessible format and is of interest to undergraduate and graduate students studying nutritional neuroscience and related disciplines, healthcare professionals with an applied interest, industry researchers seeking topic overviews, and interested general readers.
We evaluated the biphasic mood-elevating and relaxing effects of chocolate eating behavior in a context of resting during or after work or study. To evaluate these two effects, psychological, physiological and behavioral measurements were compared between before and after of their chocolate eating. Participants ate 4.6 g of chocolate between or after two sessions, 5 and 7 minutes, of tracking task. These scenarios mimicked common chocolate eating scene, work or study, where continuous concentration is to be required. As a result, eating between the task sessions improved task performance and enhanced positive mood, whereas eating after the task enhanced positive mood but also stimulated brain activity. This indicates that the psychophysiological effect of eating chocolate is not biphasic but rather monophasic, that is, a mood-enhancing effect. However, the post-task stimulation of brain activity might be context-dependent. Note that these results should be the mixed effects of food and physical activity.
Background
Recent findings suggest a possible role of diet, particularly nutrient in- takes and dietary patterns, in the prevalence of mild cognitive impairment (MCI); few studies, how- ever, have been explicitly devoted to the relationship between dietary habits and MCI.
Objectives
We aimed to explore the association between dietary habits, including meal timing, and MCI among older Chinese adults.
Methods
This cross-sectional study involved data collected at the baseline of the Tianjin Elderly Nutrition and Cognition Cohort (TENCC) study, in which 3,111 community-dwelling older adults (326 MCI patients and 2,785 non-MCIs) from a rural area of Tianjin, China, were recruited. In March 2018 to June 2019, all participants underwent a detailed neuropsychological evaluation that allowed for psychometric MCI classification. Information on self-reported dietary behaviors was gathered via face-to-face interviews. Crude and multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models.
Results
In the multivariable-adjusted models, eating breakfast 4 to 6 times per week (vs. ≤3 times per week, OR: 0.45; 95% CI: 0.26, 0.75), drinking water before breakfast (yes vs. no, OR: 0.64; 95% CI: 0.51, 0.82), consuming water ≥1.5L per day (vs. <1.5L per day, OR: 0.64; 95% CI: 0.51, 0.82), and having lunch after 12:00 (vs. before 12:00, OR: 0.59; 95% CI: 0.47, 0.75) were associat- ed with decreased risk of MCI. Participants who consumed higher amounts of cooking oil were at a higher risk of MCI (moderate vs. low, OR: 1.42; 95% CI: 1.04, 1.92; high vs. low, OR: 1.40; 95% CI: 1.07-1.83).
Conclusion
This study suggests that dietary habits, including breakfast frequency, daily water consumption, cooking oil consumption, and meal timing, may be associated with the risk of MCI. If replicated, these findings would open new possibilities of dietary interventions for MCI.
Context: Evidence suggests that plasma glucose levels may influence cognitive performance , but this has not been systematically reviewed and quantified. Objective: The aim of this review was to investigate the potential effects of glucose and sucrose, compared with placebo, on cognition in healthy humans. Data Sources: The electronic databases PubMed and Web of Science were searched up to December 2019. Reference lists of selected articles were checked manually. Study Selection: Randomized controlled trials or crossover trials that compared glucose or sucrose with placebo for effects on cognition were eligible. Data Extraction: Potentially eligible articles were selected independently by 2 authors. Risk of bias was assessed through the Cochrane Collaboration tool. Standardized mean differences (SMDs) were obtained from random-effects meta-analyses for a subsample of studies that reported the same outcomes. Results: Thirty-seven trials were identified, of which 35 investigated the effect of glucose consumption compared with placebo on cognition. Two studies found no effect of glucose on cogni-tion, while the others found mixed results. Only 3 of the 37 studies investigated the effects of sucrose intake, reporting mixed results. Meta-analyses revealed a significantly positive effect of glucose compared with control, but only when a verbal performance test (immediate word recall) was used in parallel-design studies (SMD ¼ 0.61; 95%CI, 0.20-1.02; I 2 ¼ 0%). Twenty-four studies were classified as having high risk of bias for the selection procedure. Conclusions: A limited body of evidence shows a beneficial effect of glucose in individuals performing immediate verbal tasks. High-quality trials with standardized cognitive measurements are needed to better establish the effect of glucose or sucrose on cognition.
Context:
Evidence suggests that plasma glucose levels may influence cognitive performance, but this has not been systematically reviewed and quantified.
Objective:
The aim of this review was to investigate the potential effects of glucose and sucrose, compared with placebo, on cognition in healthy humans.
Data sources:
The electronic databases PubMed and Web of Science were searched up to December 2019. Reference lists of selected articles were checked manually.
Study selection:
Randomized controlled trials or crossover trials that compared glucose or sucrose with placebo for effects on cognition were eligible.
Data extraction:
Potentially eligible articles were selected independently by 2 authors. Risk of bias was assessed through the Cochrane Collaboration tool. Standardized mean differences (SMDs) were obtained from random-effects meta-analyses for a subsample of studies that reported the same outcomes.
Results:
Thirty-seven trials were identified, of which 35 investigated the effect of glucose consumption compared with placebo on cognition. Two studies found no effect of glucose on cognition, while the others found mixed results. Only 3 of the 37 studies investigated the effects of sucrose intake, reporting mixed results. Meta-analyses revealed a significantly positive effect of glucose compared with control, but only when a verbal performance test (immediate word recall) was used in parallel-design studies (SMD = 0.61; 95%CI, 0.20-1.02; I2 = 0%). Twenty-four studies were classified as having high risk of bias for the selection procedure.
Conclusions:
A limited body of evidence shows a beneficial effect of glucose in individuals performing immediate verbal tasks. High-quality trials with standardized cognitive measurements are needed to better establish the effect of glucose or sucrose on cognition.
Systematic review registration:
PROSPERO registration number CRD42019122939.
Background:
At present, the impact of macronutrient composition and nutrient intake on sustained attention in adults is unclear, although some prior work suggests that nutritive interventions that engender slow, steady glucose availability support sustained attention after consumption. A separate line of evidence suggests that nutrient consumption may alter electroencephalographic markers of neurophysiological activity, including neural oscillations in the alpha-band (8-14 Hz), which are known to be richly interconnected with the allocation of attention. It is here investigated whether morning ingestion of foodstuffs with differing macronutrient compositions might differentially impact the allocation of sustained attention throughout the day as indexed by both behavior and the deployment of attention-related alpha-band activity.
Methods:
Twenty-four adult participants were recruited into a three-day study with a cross-over design that employed a previously validated sustained attention task (the Spatial CTET). On each experimental day, subjects consumed one of three breakfasts with differing carbohydrate availabilities (oatmeal, cornflakes, and water) and completed blocks of the Spatial CTET throughout the morning while behavioral performance, subjective metrics of hunger/fullness, and electroencephalographic (EEG) measurements of alpha oscillatory activity were recorded.
Results:
Although behavior and electrophysiological metrics changed over the course of the day, no differences in their trajectories were observed as a function of breakfast condition. However, subjective metrics of hunger/fullness revealed that caloric interventions (oatmeal and cornflakes) reduced hunger across the experimental day with respect to the non-caloric, volume-matched control (water). Yet, no differences in hunger/fullness were observed between the oatmeal and cornflakes interventions.
Conclusion:
Observation of a relationship between macronutrient intervention and sustained attention (if one exists) will require further standardization of empirical investigations to aid in the synthesis and replicability of results. In addition, continued implementation of neurophysiological markers in this domain is encouraged, as they often produce nuanced insight into cognition even in the absence of overt behavioral changes. ClinicalTrials.gov Identifier: NCT03169283.
The clinical assessment of attention depends on three primary sources of information: (1) direct behavioral observation and measurement; (2) psychometric tests designed to measure other cognitive functions (e.g., intellectual measures), which provide indirect information about attention, and (3) neurocognitive tests developed specifically to assess attention and its underlying component processes. As attention is a multifaceted process, the assessment of attention requires that the clinician obtains information about the characteristics of the patient’s performance under different conditions. Therefore, to adequately assess attention, it is usually necessary to use more than one test.
This paper summarizes some of the results obtained by our group at the Institute of Physiology in Siena where, in the 1970s, Giancarlo Carli founded the School of Sports Medicine. Carli inculcated a deep interest in the relation between cognition and physical activity in students and colleagues. The main focus of our work were the cognitive factors able to influence sport performance, their neurophysiological correlates, the effects of physical and mental training on performance, and the relation between nutrition and physical/cognitive activity. We have shown that: (a) training reduces reaction times, errors, and variability in the performance of attentional tasks; (b) the characteristics of the motor action and of the related motor cortex potential is modified by both physical and mental imagery training; (c) dietary supplementation with omega-3 fatty acids and policosanols improves reactivity and attention, modifies the profile of mood states, and induces changes in the cerebral activity associated with motor action, similar to those observed after physical training; and (d) the glycaemic index of foods is associated with specific levels of cognitive performance relevant to physical activity. We are grateful to Professor Carli to have oriented our interests, encouraged our research, and helped us with his enthusiasm and criticism.
Macronutrients have the potential to alter cognitive function by exerting effects on neuronal cell structure, neurotransmission, energy supply to the brain and metabolism. The current chapter discusses evidence for the effects of macronutrients on cognitive performance with consideration of potential moderating factors and mechanisms of action. Portion size and macronutrient composition of meals and the time of day meals are taken are considered. The effect of glucose on cognitive performance is discussed with a focus upon the impact of Glycaemic Index, Glycaemic Load and evidence for the moderating effect of fibre on glucoregulatory function. Stress and cortisol are also considered as potential moderators of the relationship between macronutrients on cognitive performance. The implications of these findings for the food industry, nutritionists and policy-makers are discussed, and future trends and opportunities for this research area are identified.
It has been 15 years since the original publication of Neuropsychology of Attention. At the time of its publication, attention was a construct that had long been of theoretical interest in the field of psychology and was receiving increased research by cognitive scientists. Yet, attention was typically viewed as a nuisance variable; a factor that needed to be accounted for when assessing brain function, but of limited importance in its own right. There is a need for a new edition of this book within Neuropsychology to present an updated and integrated review of what is know about attention, the disorders that affect it, and approaches to its clinical assessment and treatment. Such a book will provide perspectives for experimental neuropsychological study of attention and also provide clinicians with insights on how to approach this neuropsychological domain. © Springer Science+Business Media New York 2014. All rights reserved.
To investigate the effects of glucose, or a combination of saccharides, or a placebo on the memory performance of middle-aged adults.
A double-blind, placebo controlled design was used. A population-based sample of 45 men and women (aged 40-63 years) completed a series of memory tasks following administration of a single dose of either glucose, a combination of saccharides or placebo. Memory tasks included immediate and delayed recall, recognition, short-term memory, working memory, and a test of general cognitive ability.
There were no statistically significant effects of treatments on any of the outcome measures.
The pattern of means in the combination of saccharides group suggests potential enhancement effects of memory performance in middle-aged adults that deserves further investigation.
To determine the effect of 1, 2, 3, and 4% dehydration (DEH) versus euhydration (EUH) on basketball performance in adult male players.
Seventeen 17- to 28-yr-old male basketball players completed 3 h of interval treadmill walking (40 degrees C and 20% relative humidity) with or without fluid replacement. Subjects completed six trials in random order: 1) EUH with a carbohydrate-electrolyte solution (CES), 2) EUH control (flavored water with 0% carbohydrate and 18 mM sodium), 3) 1% DEH, 4) 2% DEH, 5) 3% DEH, and 6) 4% DEH. After a 70-min recovery period, subjects performed a sequence of continuous basketball drills designed to simulate a fast-paced game. Measures of overall skill performance during the 80-min game included 1) total time to complete basketball-specific movement drills (sprinting, defensive slides, sprinting-defensive slides combination, and repetitive jumping drills) and 2) total number of shots (foul-line and baseline jump shots, layups, three-point, 15-ft, free throws) made per game.
Performance during all timed and shooting drills declined progressively as % DEH increased. Total time to complete basketball-specific movement drills was slower (1%: + 7 +/- 6; 2%: + 20 +/- 5 (P < 0.05); 3%: + 26 +/- 7 (P < 0.005); 4%: + 57 +/- 9 (P < 0.0001) s), and fewer shots were made during DEH versus EUH control (1%: -5 +/- 1; 2%: -6 +/- 2 (P < 0.05); 3%: -8 +/- 2 (P < 0.005); 4%: -10 +/- 1 (P < 0.0001) shots made). There were no significant differences in performance between CES and EUH control.
Basketball players experienced a progressive deterioration in performance as DEH progressed from 1 to 4%. The threshold, or % DEH at which the performance decrement reached statistical significance, was 2% for combined timed and shooting drills.
Glucose enhances memory in a variety of individuals, including people with Alzheimer's disease. By 35 years of age, adults with Down's syndrome (DS) develop the characteristic plaques and tangles found in Alzheimer's disease, despite findings indicating that not all older DS individuals meet criteria for dementia. To examine the possibility that glucose enhances memory in adults with DS (mean age = 35 years, range = 19–55 years), adults with DS were given a battery of tests specifically designed for individuals with DS in glucose and control conditions. No participant met criteria for dementia, regardless of age. Glucose enhanced performance on tests requiring both long-term memory and auditory processing. In addition, increased age was associated with poorer performance on the majority of tests in the control condition, indicating that cognitive decline with aging may be more prevalent in DS than previously believed.
Administration of epinephrine and glucose, as well as drugs that influence cholinergic and opiate systems, can enhance or impair memory. The present experiments examined the possibility that peripheral glucose administration might reverse scopolamine- and morphine-induced impairments in a spontaneous alternation task. Mice received all drug administrations 30 min before testing. Scopolamine-induced (3 mg/kg), deficits in alternation performance were reversed by glucose (100 and 250 mg/kg) amphetamine (1 mg/kg), epinephrine, physostigmine, and oxotremorine (each 0.1 mg/kg). Morphine (10 mg/kg) also impaired spontaneous alternation performance, and glucose (100 and 300 mg/kg) reversed this impairment as well. These findings are consistent with the view that central cholinergic systems, possibly under inhibitory opiate regulation, may contribute to glucose and epinephrine effects on memory storage.
Amphetamine, epinephrine, and glucose enhance memory storage when administered shortly after training. Amphetamine enhancement of memory storage may be mediated by peripheral epinephrine actions, and epinephrine enhancement of memory storage may involve increases in blood glucose levels. Amphetamine and possibly epinephrine also enhance memory retrieval when administered shortly before testing. To examine the parallels in pharmacological enhancement of memory storage and retrieval, we tested the effects on memory of injections of amphetamine (1.0 mg/kg), epinephrine (0.05 mg/kg), or glucose (100 mg/kg) administered prior to retention tests in mice. Mice were trained in a one-trial inhibitory (passive) avoidance task. Thirty minutes prior to testing, each mouse received an injection of saline, amphetamine, epinephrine, or glucose. In a second experiment, rats were trained on a one-trial inhibitory avoidance task and were administered glucose (100,250, or 500 mg/kg) prior to testing. The results indicate that amphetamine, epinephrine, and glucose all significantly enhanced learned performance, supporting the view that similar neuroendocrine systems may contribute to both memory storage and retrieval. In addition, these findings provide another demonstration that peripheral glucose injections modify behavior.
Optimization of cognitive processing may depend on specific and distinct functions of the cortical cholinergic and noradrenergic systems. This investigation dissociates functions of cortical acetylcholine (ACh) and noradrenaline (NA) in arousal and visual attention by simultaneously measuring ACh and NA efflux in the rat prefrontal cortex during sustained attentional performance. The five-choice serial reaction time task was used to provide a continuous assessment of visuospatial attention. Previous studies using this task have established a critical role for the cortical cholinergic system in the detection of visual targets. However, selective lesions of the locus coeruleus noradrenergic system impair performance only when additional attentional demands are placed on the subject by distractors or temporally unpredictable targets. To test the hypothesis that the cortical noradrenergic system is particularly sensitive to novel task contingencies, we also assessed NA and ACh efflux in rats that been trained previously on the task but for whom the instrumental contingency coupling responding with stimulus detection and reward was abolished. Cortical ACh efflux showed a robust and task-related increase during established contingent performance. This response was significantly attenuated in noncontingent subjects, although it still exceeded pretask values. In contrast, NA efflux only increased transiently in contingent subjects after task onset but showed sustained elevations in noncontingent subjects on the first day when contingencies were changed. These data also implicate cortical ACh in aspects of attentional functioning but highlight a specific involvement of the cortical noradrenergic system in detecting shifts in the predictive relationship between instrumental action and reinforcement.
There have been many suggestions that both dietary sugar and the level of blood glucose may be associated with abnormal behaviour. To examine this question 60 six- and seven-year old children were given a drink that contained either 25 grams of glucose or a placebo towards the end of the school day. They were then subjected to one test that required sustained attention and to a second that was intentionally frustrating. Those given the drink containing glucose were more capable of sustaining attention and showed fewer signs of frustration.
In the present investigation, we sought to determine whether glucose could enhance declarative memory in head-injured individuals, as has been shown previously with elderly and Alzheimer's patients who had preexisting memory impairments. Varsity rugby players, both with and without a history of concussions, were given glucose- or saccharin-sweetened beverages and then tested on a series of neuropsychological tests of attention and memory; their blood-glucose levels were monitored. Beverages and tests were administered in a counterbalanced, crossover design, enabling within-subjects comparisons. Previously concussed participants were found to perform slightly worse than participants with no history of concussions (controls) on the preliminary screening interview tests and tests of memory and divided attention given in the saccharin (placebo) condition. Glucose was shown to enhance performance of the previously concussed participants and impair the performance of controls on tests of long-term declarative memory. The effects of glucose on memory appeared to be related to the participants' ability to clear glucose from the blood.
Introduction. It has been suggested that the behavioral manifestations of attention deficit hyperactivity disorder (ADHD) are secondary to neurological abnormalities and are characterized as low brain wave disorders. ADHD children produce higher amounts of theta (5-7 Hz) and less beta (13-21 Hz) brain wave activity than normals. Many researchers are testing the therapeutic effectiveness of AudioVisual Entrainment (AVE) as a treatment for a variety of low arousal brain disorders. AVE is the repetitive and intermittent presentation of light and sound. AVE affects electroencephalographic (EEG) output in that brain wave output can be suppressed or enhanced at specific frequencies.Procedure. Thirty-four elementary students from two different schools were given AVE over the course of seven weeks. Participants were given the Test of Variables of Attention (TOVA) before and after participation. A second group of eight participants were in a special reading (SPALDING) class. All of the students in this class received the Standardized Test for the Assessment of Reading (STAR) and were compared with a control group, n = 12.Results. Overall inattention, impulsivity and variability as rated by the TOVA improved significantly. The eight students from the SPALD-ING reading program who received AVE improved their reading scores more than their classmates who served as controls. The results included normalization as recorded on the TOVA, substantial improvements in reading as recorded on the STAR, and improvements in general behavior as noted by teachers and parents.Discussion. The data suggests AVE was a useful experience for the participants. Parents and teachers reported the children were calmer and could focus better. The results met or exceeded our expectations.
Examined whether disrupting circadian light–dark rhythms leads to impairments in memory in mice using a retrieval design and whether glucose or epinephrine could attenuate deficits in memory. Ss were first trained on an inhibitory avoidance task during the light portion of the illumination cycle. Ss were then maintained for a 72-hr train–test interval either under the same schedule of illumination or one with a phase advance of 4 hrs. 30 min before testing, Ss were injected with saline, glucose (1, 10, 100, 250, or 500 mg/kg), or epinephrine. Retention was significantly impaired in phase-shifted mice relative to nonphase-shifted controls. Glucose (100 mg/kg) and epinephrine attenuated the deficit in memory. Altered illumination schedules appear to disrupt memory in mice as well as in rats, and glucose may be a useful treatment for attenuating deficits in memory associated with impaired biological rhythms. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Examined effects of glucose on memory in 2 amnesic populations (mice treated with scopolamine [SCO] and old mice) and assessed effects of glucose on brain [–3H]2-deoxyglucose (2DG) uptake. In Exp 1A, SCO significantly impaired performance of Ss tested in a spontaneous alternation task. Glucose administered with SCO attenuated the deficit in alternation performance. SCO also resulted in significant reductions in brain 2DG uptake in the hippocampus and thalamus (Exp 1B). Glucose administered with SCO attenuated SCO-induced reductions in 2DG uptake. Glucose similarly enhanced spontaneous alternation behavior (Exp 2A) and hippocampal 2DG uptake (Exp 2B) in 2-yr-old mice. Thus, the brain seems to become more sensitive to circulating glucose in several amnestic conditions. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Circulating glucose concentrations regulate many brain functions, including learning and memory. Much of the evidence for this view comes from experiments assessing stress-related release of epinephrine with subsequent increases in blood glucose concentrations. One application of this work has been to investigate whether age-related memory impairments result from dysfunctions in the neuroendocrine regulation of the brain processes responsible for memory. Like humans, aged rodents exhibit some memory impairments that can be reversed by administration of epinephrine or glucose. In elderly humans, ingestion of glucose enhances some cognitive functions, with effects best documented thus far on tests of verbal contextual and noncontextual information. Glucose also effectively enhances cognition in persons with Alzheimer disease or Down syndrome. Although earlier evidence suggested that glucose does not enhance cognitive function in healthy young adults, more recent findings suggest that glucose is effective in this population, provided the tests are sufficiently difficult. In college students, glucose consumption significantly enhanced memory of material in a paragraph. Glucose also appeared to enhance attentional processes in these students. Neither face and word recognition nor working memory was influenced by treatment with glucose. The neurobiological mechanisms by which glucose acts are under current investigation. Initial evidence suggests that glucose or a metabolite may activate release of the neurotransmitter acetylcholine in rats when they are engaged in learning. Consequently, the issue of nutrition and cognition becomes increasingly important in light of evidence that circulating glucose concentrations have substantial effects on brain and cognitive functions.
It is well established that posttraining administrations of glucose enhance memory in a time- and dose-dependent manner. More recently, glucose has also been found to attenuate scopolamine-induced anterograde amnesia, displaying the same time- and dose-response characteristics (Stone et al., 1988). In the present study, the use of glucose as an agent for alleviation of hypothermia-induced retrograde amnesia was examined. In each experiment, animals were given a single trial of passive avoidance conditioning. Retrograde amnesia was induced through hypothermia immediately following training. All injections were given immediately following hypothermia treatment, and tests for fear retention were administered 24 h following training. In Experiment 1, the dose-response effects of glucose (10, 100, or 400 mg/kg) were examined; in Experiment 2, the time-dependent effect of 100 mg/kg of glucose administered immediately, 1, or 2 h after hypothermia was examined. The results show that glucose injections attenuate retrograde amnesia in both a dose- and time-dependent manner. These results coincide with the growing body of evidence supporting the memory-modulating effects of glucose.
A passive avoidance to active avoidance negative transfer paradigm was used to investigate the effects of glucose on recently acquired and recently reactivated memories. Immediate post-passive avoidance training injections of glucose (100 mg/kg s.c.) improved memory and thus interfered with the rats’ ability to learn the one-way active avoidance task 24 h later. Rats receiving a memory reactivation treatment 24 h after passive avoidance training showed greater negative transfer to the active avoidance task presented 24 h later than did nonreactivated control animals. Furthermore, the administration of glucose (32, 100, or 320 mg/kg) following memory reactivation proactively interfered with the acquisition of the active avoidance; this effect followed an inverted U-shaped dose-response function. The ability of glucose (100 mg/kg) to alter the reactivated passive avoidance memory decreased as the interval between reactivation and glucose treatment was increased up to 30 min. These results demonstrate that glucose modulates the processing of old memories that have been recently reactivated, just as it modulates the processing of new memories that have been recently acquired.
This book looks at what we have learned over the last century in attempting to discover how the brain enables us to acquire, retain, and use information based on experiences. The major central questions posed in the book are: What processes underlie the formation of new memories? What processes determine the strength of memories? Where are the changes underlying memory located? The chapters in this book review recent progress in research investigating emotion and memory, aging and memory, plasticity of the cerebral cortex, and synaptic connectivity and memory. William James, Ivan Pavlov, Karl Lashley, Donald Hebb, and the other pioneers in this field would, of course, find these topics familiar. But they would also find that in recent years these topics have been investigated in unexpected ways and that the findings have greatly expanded the questions that can be asked as well as the experimental techniques that can be employed.
This chapter integrates and organizes pharmacological studies of memory by searching for generalizations or "rules" about the roles of hormonal and neurotransmitter systems in the regulation of learning and memory processes. In doing so, it is important to examine carefully the extent to which these generalizations are similar and different for results obtained with systemic injections and those obtained with direct brain injections. Consistently, systemic injections of epinephrine or of glucose, which may contribute to epinephrine effects on memory, enhance memory when administered near the time of training. Similarly, systemically administered drugs that promote the functions of central cholinergic, glutaminergic, or noradrenergic systems enhance memory on later tests. Moreover, diminished release of the neurotransmitters or pharmacological blockade of their receptors can impair memory. There also appear to be some neurochemical systems, for example, opioid and GABA, for which activation impairs, and inactivation enhances, learning and memory.
Peripheral glucose ingestion enhances performance on explicit declarative verbal memory tasks in healthy elderly people. In the present experiment, healthy young and elderly adults were administered glucose (50 g) or saccharin followed by tests of declarative verbal memory (free recall and recognition of a word list) and a nondeclarative priming test (word-stem completion). In the elderly, glucose significantly enhanced performance on the declarative but not on the nondeclarative portions of the test. Performance by the young subjects was equivalent in the glucose and saccharin conditions. These findings, that glucose enhances memory for a declarative/explicit but not nondeclarative/implicit task, support the notion that declarative and nondeclarative memory systems are separate functional and anatomic systems.
An instance theory of attention and memory (ITAM) is presented that integrates formal theories of attention and memory phenomena by exploiting commonalities in their formal structure. The core idea in each theory is that performance depends on a choice process that can be modeled as a race between competing alternatives. Attention and categorization are viewed as different perspectives on the same race. Attention selects objects by categorizing them; objects are categorized by attending to them. ITAM incorporates each of its ancestors as a special case, so it inherits their successes.
The effect of hyperglycemia on hormone levels, metabolite levels, and memory performance was examined in 22 subjects with very mild and mild probable dementia of the Alzheimer type (DAT) and in 12 normal elderly adults. Subjects were tested in 3 plasma glucose conditions (fasting baseline, 175 mg/dl, and 225 mg/dl) at initial and 18-month follow-up sessions. Initially, adults with very mild DAT showed memory facilitation and elevations in plasma insulin in the 225-mg/dl glucose condition relative to baseline. At follow-up, very mild DAT patients whose dementia had progressed showed significant decreases in insulin and hyperglycemic memory facilitation
Attention is a complex process whose disturbance is considered a core deficit in a number of disorders [e.g., Attention Deficit Hyperactivity Disorder (ADHD), schizophrenia]. In 1956, Rosvold and colleagues [J. Consult. Psychol. 20 (1956) 343.] demonstrated that the continuous performance test (CPT) as a measure of sustained attention was highly sensitive to brain damage or dysfunction. These findings have been replicated with various populations and with various versions of the CPT. The CPT is now cited as the most frequently used measure of attention in both practice and research. Across studies, results are consistent with models of sustained attention that involve the interaction of cortical (frontal, temporal, parietal), subcortical (limbic, basal ganglia), and functional systems including the pathways between the basal ganglia, thalamus, and frontal lobes. Right hemisphere involvement (asymmetric response) is also evident across multiple studies. As such, the CPT demonstrates sensitivity to dysfunction of the attentional system whether this is due to diffuse or more focal damage/dysfunction or in conjunction with any specific disorder. CPT performance can be viewed as symptom specific (attentional disturbance), but it is not disorder specific (e.g., ADHD). Implications for neuropsychological interpretation of CPT results are presented.
A continuous performance test of attention (SCAT; Seidel Continuous Attention Test) was administered to 128 normative subjects and 22 subjects diagnosed with attention deficit disorder with hyperactivity (ADDH), who ranged in age between 6 and 11 years. Overall performance was related to age, while reaction time was also significantly related to gender. Significant correlations were obtained between performance on the SCAT and (1) teacher ratings of school performance, (2) those subtests of the Wechsler Intelligence Scale for Children-Revised (WISC-R) that have been reported to load on an attention factor, and (3) particular factor scales obtained from the Conners Parent and Teacher Questionnaires. Significant differences in performance were revealed between ADDH and matched control groups on the SCAT. Preliminary evidence is presented on the validity and reliability of the SCAT as a measure of attention.
Recent experiments indicate that peripheral glucose administration enhances memory in rodents and humans. This study examined the effects of glucose on memory and nonmemory measures of neuropsychological functioning in elderly humans. Healthy older adults were given a series of neuropsychological tests after drinking glucose- or saccharin-flavored lemonade. A repeated measures design using counter-balanced beverages and tests was used. Glucose enhanced performance on declarative memory tests but not on short-term or nonmemory neuropsychological measures. Glucose tolerance predicted performance on declarative memory tasks but not on other measures.
: The monoaminergic and cholinergic systems are implicated in different forms of behavioral arousal that can be dissected in terms of their forebrain targets and the nature of the behavioral processes they modulate in distinct regions. Thus, evidence in rats with selective neurochemical manipulations tested behaviorally using an analog of an attentional task developed for human subjects indicates that the coeruleo-cortical noradrenergic system is implicated in divided and selective attention, the basal forebrain cholinergic system in stimulus detection, the mesostriatal and mesolimbic dopaminergic systems in response speed and vigor, and the mesencephalic serotoninergic or 5-HT systems in response inhibition. Our recent studies have focused on fractionating, in the same task, the differential contributions of the dorsal and median raphé 5-HT systems as well as elucidating the functions of the mesocortical dopaminergic system, each of which may be relevant to understanding the behavioral and cognitive sequelae of cocaine administration in human subjects as well as in experimental animals.
Used frequently in the assessment of attention deficit hyperactivity disorder (ADHD), continuous performance test (CPTs) still lack sufficient empirical support for such use. Recently developed inattention, impulsivity, and dyscontrol scores incorporate both error speed and error type. Our study of 23 boys with ADHD and 15 comparison boys (6-12 years old), replicated findings that the inattention ad dyscontrol indices, but not the impulsivity index, discriminate the ADHD and non-ADHD groups. The impulsivity index, however, discriminated aggressive from nonaggressive groups among the youngsters with ADHD. The dose response patterns of the CPT error scores to stimulant medication were similar to those for naturalistically observed aggression and noncompliance. As for external validity, the CPT scores were weakly related to dimensional measures of observed aggression, but unrelated noncompliance. Although between-group differences were clear in the group data, the CPT revealed adequate specificity but poor sensitivity in identifying individual boys with ADHD. Results only partially support the ecological validity of the CPT and suggest that CPT error scores function differentially depending on the validation task used; extreme scores may have clinical meaning in assessment of youngsters with ADHD.
Compared children with attention deficit hyperactivity disorder (ADHD) with normal and abnormal continuous performance test (CPT) scores. Children with normal scores showed less inattention and more conduct and psychosomatic problems on Conners Parent Rating Scale and Teacher Rating Scale ratings, and performed more normally on other laboratory measures. A drug trial showed that they were less likely to respond positively to stimulant medication, and less likely to do well on a higher dose than a lower dose when response was documented. The results suggest that CPTs can identify clinically meaningful differences between children referred for ADHD evaluations.
Previous research has shown that glucose can enhance memory in animals and humans. In humans, the facilitative effect of glucose is best observed with declarative memory tasks in older subjects. While the memory-enhancing action of glucose is well established, the underlying physiological mechanisms and the specific aspects of memory that are modulated by glucose in humans are not well understood. The present study sought to examine the effects of glucose on memory in young women using a memory paradigm sensitive to specific encoding and retrieval strategies. The glucose dose was adjusted for the weight of each participant in order to generate a dose response curve covering most doses used in previous studies. The results showed that 300 mg/kg glucose enhanced the primacy effect as defined by the recall of the first five items of the lists. However, none of the doses of glucose produced changes in the recall priority given to primacy items. The effect of glucose appears to be localized on the recall primacy effect, suggesting that glucose acts on precise memory operations. This improvement, however, is independent of the order in which subjects recalled the words. Cholinergic drugs have been shown to alter the recall of the primacy part of word lists and this observation is consistent with the hypothesis that glucose acts on memory through an interaction with brain cholinergic systems.
The purpose of this case study was to evaluate the effects of alpha-increase biofeedback training on human attention. A healthy twenty-three year old male college student had undergone twenty-three sessions of alpha- increase biofeedback (8–13 Hz) at PZ electrode site for a period of eleven weeks. Pre-and Post- visual TOVA CPT test was administered to assess the changes in reaction times and their variability. QEEG evaluation was conducted prior as well as upon the completion of the study. The results of the TOVA test clearly indicate an improvement in individual's reaction time and the reaction time variability. Statistical analysis showed that before and after QEEG evaluations were within normal limits.
Six middle school students diagnosed with attention deficit/hyperactivity disorder were selected for sensorimotor rhythm (SMR) training with EEG biofeedback. The subjects were evaluated following a 72-hour drug-free period with the WISC-III Digit Span subtest and the Test of Variables of Attention (TOVA). Five of the subjects received 20 sessions of EEG biofeedback and one of the subjects received nine sessions of EEG biofeedback. The subjects were evaluated again following a 72-hour drug-free period. Five of the six subjects improved on their combined Digit Span, TOVA Inattention, and TOVA Impulsivity scores. These results supported previous findings that EEG biofeedback can be effective in the treatment of attention deficit/hyperactivity disorder. More importantly, this study demonstrated that EEG biofeedback could be used in an actual school setting. Recommendations for implementing an EEG biofeedback program in the schools were provided.
Objective:
To examine the effects of sugar on the behavior or cognition of children by using meta-analytic techniques on reported studies.
Data sources:
Studies were identified through a literature search of the MEDLINE and PsychINFO databases and the authors' files using sugar, sucrose, and attention deficit disorder as the search terms.
Study selection:
Studies were required to (1) intervene by having the subjects consume a known quantity of sugar, (2) use a placebo (artificial sweetener) condition (3) blind the subjects, parents, and research staff to the conditions; and (4) report statistics that could be used to compute the dependent measures effect sizes.
Data extraction:
Variables included publication year, study setting, subject type and number, gender, age, sugar and placebo type and dose, prior dietary condition, measurement construct, means and SDs for the sugar and placebo conditions, and direction of effect.
Data synthesis:
Sixteen reports met the inclusion criteria for a total of 23 within-subject design studies. The weighted mean effect size and related statistics for each of the 14 measurement constructs revealed that although the range for these means was from -0.14 for direct observations and up to +0.30 for academic tests, the 95% confidence interval for all 14 mean effect sizes included 0.
Conclusion:
The meta-analytic synthesis of the studies to date found that sugar does not affect the behavior or cognitive performance of children. The strong belief of parents may be due to expectancy and common association. However, a small effect of sugar or effects on subsets of children cannot be ruled out.
The study reports on Patient-Directed neurofeedback for Attention Deficit/Hyperactivity Disorder (AD/HD). Therapist involvement was limited to 10 treatment sessions used to train the patient or parents of younger children to use the equipment, to monitor treatment, and to make changes in the treatment protocol as necessary. The remaining 50 sessions were conducted at home using inexpensive, easy to operate, 1 or 2 channel Lexicor PODS. Results from the initial 6 patients, ages 7 to 45, are reported. Thirteen of 24 Test of Variables of Attention (TOVA) measures (attention, impulsivity, reaction time and variability) were below average (SS c 90) at baseline. After 30 neurofeedback sessions, only 5 TOVA variables remained below average. It is concluded that Patient-Directed neurofeedback may be an effective alternative to Therapist-Directed treatment for many AD/HD patients and can be delivered at substantially less cost.
reviewed the considerable evidence that epinephrine modulates memory processes—the major contribution being an increase in circulating glucose levels as a result of epinephrine effects on memory and other brain functions
this review will: 1) examine the findings which justify this current view of epinephrine and glucose as peripheral factors which modulate memory storage processes, 2) describe pharmacological interactions contributing to epinephrine and glucose effects on memory, and 3) consider the application of these findings to one area of memory impairment, aging
conclude with some suggestions regarding further directions for determining the mechanisms by which glucose regulates memory formation (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Administered complex tests of declarative memory, working memory, procedural learning, and response generation and inhibition to 27 younger adults (14 men and 13 women; aged 19–28 yrs) and 32 older adults (16 men and 16 women; aged 58–77 yrs) following ingestion of saccharin or glucose. Glucose administration (GLA) significantly enhanced performance on the declarative memory measure paragraph recall for older men and younger men whose blood glucose returned to similar levels. Younger men whose blood glucose levels were lowest 60 min after glucose ingestion showed memory deterioration. GLA did not affect paragraph recall for the other groups, nor were effects noted for any group for most other cognitive measures. Results suggest that the effects of GLA are primarily restricted to declarative memory independent of task complexity, and that age, sex, and glucoregulatory response may influence hyperglycemic memory enhancement. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The emergence of the sociocultural perspective in cross-cultural psychology has discouraged the adaptation of standardized tests in nonindustrialized settings. Yet, cognitive assessments are needed for monitoring the effects of nutritional, health, and educational interventions. Forty-seven Lao children 5 to 12 years of age completed the Kaufman Assessment Battery for Children (K-ABC), the Tactual Performance Test (TPT), and the computerized Tests of Variables of Attention (TOVA). TPT performance measures were related to physical (nutritional) development, whereas the K-ABC global cognitive ability indicators were sensitive to parental education and quality of home environment. TOVA performance was related to K-ABC global performance and TPT memory, suggesting that these measures are at least partially undergirded by attentional ability. Sociocultural concerns aside, these findings suggest that validated neuropsychological and cognitive assessments can be adapted that effectively tap basic and universal brain-behavior traits. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
describes evidence for epinephrine and glucose enhancement of memory, as well as early findings relevant to their mechanisms of action, and then discusses epinephrine and glucose attenuation of memory impairments in animals and humans during aging and after brain injury (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The Continuous Performance Test (CPT), such as the Test of Variable Attention (TOVA), is widely used in the assessment of ADHD with other behavioral ratings and observations. Since some clinicians argue that CPTs measure psychomotor speed function rather than sustained attention, a correlation study between PIQ of WISC-III and TOVA was conducted to find out if a significant relationship of any kind existed. Forty children with ADHD were studied, and the results indicated that there was no correlation between TOVA and PIQ of WISC-III. © 1999 John Wiley & Sons, Inc.
This study compared the utility of four theories of impulsivity that differ in whether they attribute impulsivity-related differences in performance to differences in arousal, differences in attentional processes or differences in nonattentional processes. Based on self-report, subjects were categorized as high or low in two forms of impulsivity, dysfunctional and functional, and two forms of arousal, tense and energetic. The four theories made differing predictions about the relationship between dysfunctional impulsivity, energetic arousal, and subjects' performance on a visual search task whose attentional demands were manipulated. It was found that higher levels of energetic arousal were associated with faster performance for high dysfunctional impulsives and slower performance for low dysfunctional impulsives only when the task was attention-demanding, supporting the theory that impulsivity-related differences in performance are due to differences in the mechanisms that allocate attention. Functional impulsivity showed complex interactions with both tense and energetic arousal; these were explained in terms of the effects of tense arousal on functional impulsives' levels of cautiousness, and the effects of energetic arousal on their ability to shift attention rapidly.
The memory-improving action of post-training, noncontingent injections of glucose was investigated in a series of experiments which examined the effects of several substances that interact with glucose metabolism on the retention of a conditioned emotional response and on blood glucose levels in male hooded rats. Although post-training glucose injections of 1, 2, and 3 g/kg all produced similar increases in blood glucose, only 2 g/kg improved retention, suggesting that attainment of a particular blood glucose level is not critical for memory improvement. Post-training injections of a range of insulin doses (0.25–4 IU/kg) failed to affect retention. Post-training injection of fructose (the same doses as were used for glucose) had no effect on blood glucose levels and, as with glucose, only the 2 g/kg dose improved retention. This finding suggests that blood glucose levels are not critical for the memory-improving effect, that glucose and fructose may act on the same substrate and, because fructose does not act directly on the brain, it raises the possibility that both substances act peripherally. Post-training injections of 2-deoxyglucose and 3-O-methylglucose both improved retention. The fact that these mostly nonmetabolized glucose analogs were effective suggests that the memory-improving action of glucose may depend on the activation of a membrane glucose transport mechanism. The implications of the possible action of glucose on peripheral transport mechanisms for understanding the effect of reinforcers on memory are discussed.
Preference curves were generated by comparing 14 concentrations each of sucrose and saccharin in a 20-minute test in which rats were presented with a choice of a sweet solution and water. The most preferred concentration and one concentration above and one below the most preferred for both substances were studied further. The sucrose and saccharin solutions were contingently paired with novel flavors in a conditioned taste preference (CTP) paradigm. All of the sweet solutions enhanced the animals' subsequent conditioned taste preferences for the flavors. The lack of difference between the effects of the solutions in this paradigm suggest that they had similar rewarding values and that CTP's are established mainly on the basis of taste cues. In another experiment, post-training ingestion of sucrose solutions, injection of glucose and, to a much lesser extent, ingestion of saccharin solutions retroactively and non-contingently improved retention of a previously formed, classically conditioned association. The results indicated that this effect was mainly due to the post-ingestional effects of the sucrose solutions, although taste factors also had a slight influence. This series of experiments parallels previous findings with self-stimulation as the reinforcer. The results support the hypothesis that reinforcers have a dual action on behavior: the elicitation of affective states that, when paired with environmental stimuli, can influence future behavior towards those stimuli; and a non-contingent retroactive enhancement of retention of previously formed associations.
Epinephrine, derived from the adrenal medulla, enhances memory storage for several forms of learning. One physiological action of this hormone is to liberate hepatic glucose stores. This experiment tested the possibility that glucose could itself enhance memory. Rats were water deprived, pretrained to drink, pretrained to drink in the behavioral apparatus, and then trained in a one-trial inhibitory (passive) avoidance task. Immediately after the training footshock, the animals each received an injection of glucose (1.0–500 mg/kg). When tested for retention 24 h later, the animals which received 10 or 100 mg/kg doses of glucose exhibited enhanced retention performance; higher and lower doses had no significant effect on the memory tests. Also, glucose injections (100 mg/kg) delayed by 1 h after training had no effect on the retention tests. These findings suggest that the increase in plasma glucose levels subsequent to epinephrine injection may contribute to the effects of epinephrine on memory. In addition, the results suggest that peripheral glucose levels may exert important influences on memory storage.
Glucose has been found to improve memory in animals and humans. Animal research has revealed that glucose may improve memory through a facilitation of acetylcholine (ACh) synthesis and release in the brain. This glucose-related memory improvement has prompted research in elderly humans. These studies have shown that the memory-improving action of glucose depends on each individuals' blood glucose regulation. Based on these data, researchers have evaluated the effect of glucose on memory in patients with Alzheimer's disease (AD). Results demonstrated that glucose could improve memory in a subset of patients that had abnormalities in their blood glucose regulation. Interestingly, these alterations in blood glucose regulation were believed to depend on the severity of the disease process. Another line of investigation has focused on alterations in brain glucose metabolism. Both animal models and studies with Type II diabetic elderly patients have shown that altered glucose regulation impairs learning and memory processes. It is possible that in AD patients, hyperglycemia exerts a deleterious effect by potentiating the neuronal death produced by other pathological processes taking place such as amyloid deposition. Based on these data, it appears important to find the prevalence of altered glucoregulation at various stages of AD. Secondly, it may be of interest to determine prospectively whether altered glucoregulation is linked to a faster progression of the disease. Finally, if such a relationship is observed, the next logical step would be to determine whether AD patients could benefit from treatments aimed at normalizing blood glucose regulation and improving insulin sensitivity.
Psychometric properties of the Test of Variables of Attention (TOVA) were examined in a cohort of children (n=63) strictly diagnosed with attention-deficit/hyperactivity disorder (AD/HD). Internal consistency was assessed via correlational
analyses to determine the degree of agreement among various test portions. The temporal stability of errors of omission, errors
of commission, response time, and response time variability was evaluated using test–retest reliability. Reproducibility of
individual scores for the same indices was assessed using the Bland–Altman procedure. Select TOVA index scores exhibited high
internal consistency in this cohort. Although the temporal stability of group scores (test–retest reliability) was satisfactory,
individual test scores were less reproducible. Temporal stability and individual test–retest score agreement were greater
for response time and response time variability than for errors of omission and errors of commission.
Behavioural studies in both humans and animals have shown that an acute rise in circulating glucose levels at or around the time of training enhances subsequent retention performance and can also afford protection from the amnesia produced by posttraining injections of scopolamine. In an attempt to directly investigate the neurochemical basis for these effects of glucose we have tested the hypothesis that raised glucose levels may enhance acetylcholine (ACh) synthesis and release in the brain during conditions of increased neuronal activity, induced either by training or pharmacological challenge, via a microdialysis study using rats. Microdialysate concentrations of ACh overflow from the hippocampus of fasted rats induced by i.p. injections of scopolamine (1 mg/kg) combined with concurrent s.c. injections of either glucose (2 g/kg) or saline were compared in successive 15-min samples using an on-line HPLC system. Scopolamine injections resulted in an immediate 10-20-fold increase in hippocampal ACh overflow which subsequently progressively declined over a 4-h period to pretreatment baseline levels. The combined injection of glucose with scopolamine resulted in a highly significant enhancement (19.4%; P less than 0.01) in ACh content of the first two samples as compared to saline-injected controls. These results provide the first direct experimental evidence that raised glucose levels, via increased availability of acetyl-coenzyme A (acetyl-coA), transiently facilitates ACh synthesis and release during conditions of increased neuronal activity. This enhancement of ACh availability during states of cholinergic neuronal activation may underlie the previously observed facilitatory effects of glucose on memory performance and its protection from scopolamine-induced amnesia.
The present experiment examined anterograde and retrograde enhancement of memory storage by glucose in elderly humans. Glucose (50 g) or saccharin was administered shortly before or immediately after acquisition of a narrative prose passage. Recall was tested 24 h later. Glucose administration before or after presentation of the material to be learned significantly improved recall 24 h later compared to performance in the saccharin condition. These findings suggest that glucose retroactively enhances memory storage processing in elderly humans and that the enhancement of memory outlasts the transient elevations in blood glucose levels after glucose ingestion.
The hypothesis that blood glucose levels influence memory was re-examined. The performance on two memory tests was quicker when breakfast had been taken, suggesting that the ability to retrieve memories had been facilitated. Performance on a spatial memory test correlated significantly with blood glucose levels.
Glucose utilization appears to play a role in memory, and patients with Senile Dementia of the Alzheimer Type (SDAT) show particular abnormalities of the glucose system. The present study examined the effects of glucose administration on memory in subjects with mild SDAT and age-matched controls. SDAT subjects demonstrated greater overall increases in blood glucose levels following glucose administration. Normal subjects whose blood glucose levels returned to near baseline following glucose administration showed facilitated memory performance, whereas SDAT subjects whose blood glucose levels remained elevated showed significant improvement following glucose administration. The results suggest that impaired glucose regulation contributes to memory impairment in SDAT.
In animals, enhancement of memory with glucose and many other treatments is characterized by an inverted-U dose-response curve. The present experiment examined the dose-response curve for glucose enhancement of memory in elderly humans. Using a repeated measures, counterbalanced, crossover design, the subjects (60-82 year olds) were tested on four sessions, separated by 1 week or more, for performance on the Wechsler Logical Memory Test after ingestion of a fruit drink sweetened with glucose (0, 10, 25, and 50 g) and saccharin matched to comparable taste. The findings indicate that glucose enhanced performance on this test in an inverted-U dose-response manner, with optimal enhancement obtained at the 25 g glucose dose. These findings provide further demonstration of glucose enhancement of memory in elderly humans and also describe an additional analogy between the characteristics of glucose enhancement of memory in animals and humans.