Maintaining Cognitive Performance at the Expense of Gait Speed for Asymptomatic Concussed Athletes: A Novel Dual-Task and Post-Exercise Assessment.

Our goal was to evaluate persisting deficits in gait and executive functioning in asymptomatic athletes with a history of concussion using a novel approach combining a dual-task paradigm and post-exercise exertion. Thirty-eight athletes aged 17 to 25 years old participated in the study, including 18 with a history of concussion. The dual-task paradigm required walking continuously at a predetermined self-paced target speed of 6.5 km/h while executing a complex switch task. Athletes completed two conditions, each on separate days: (1) dual task alone and (2) dual task following 20 min of running on a non-motorized treadmill. The statistical analyses revealed a significant reduction in gait speed exclusively for athletes with a history of concussion and only following the post-exercise condition (p = 0.008). These findings suggest that although asymptomatic concussed athletes maintain a cognitive performance comparable to non-concussed athletes, this appears to be achieved at the expense of gait speed. Our results underscore the importance of incorporating gait assessments and post-exercise exertion into concussion evaluation protocols in both research and clinical settings.

Hard-Headed Decisions: Intrapersonal Factors Underlying Concussion Reporting in University Athletes.

Most of the research investigating sports concussion (SC) disclosure has been conducted using questionnaires with a pre-determined set of questions. Hence, significant gaps remain in our understanding of which factors weight in the decision-making process underlying SC disclosure and how they contribute to it. This present study aims to fill some of these gaps using qualitative methods to identify intrapersonal determinants of SC disclosure and describe their influence on an athlete's decision-making process. Our results are based on in-depth, semistructured interviews (range, 56-79 min; total = 587 min) with 9 university athletes (5 females, 4 males) from three team sports (soccer, rugby, and cheerleading). Using constant comparative analysis guided by Straussian grounded theory, we identified 13 concepts, across three major intrapersonal categories (i.e., attitudes and behaviors; concussion knowledge; and subjective evaluation of the concussion), contributing to SC disclosure, including novel determinants such as prioritization of athletic versus intellectual activities and maturity level. Our results suggest that a comparison between experiential knowledge and severity of the injury plays a major role in determining an athlete's disclosure behaviors. Athletes with a history of concussion seem to adopt a non-disclosure default strategy and are inclined to disclose their concussion symptoms only if they judge their current concussion to be worse than their previous most severe injury. Other concepts identified appear to contribute to the decisional process by modulating the adoption of this non-disclosure default strategy. Our work highlights the benefits and necessity of using qualitative methods to study the decision-making process underlying concussion disclosure.

Psychometric properties of a color-shape version of the switch task.

The current study aims to examine the psychometric properties of a color-shape version of the switch task. In Study 1, 128 participants completed a battery of standardized measures of executive functions (EFs) as well as the switch task to determine the construct validity of three traditionally computed costs (global, switch, and mixing) and primary variables (accuracy [ACC], reaction time [RT], and inverse efficiency score [IES] of the heterogeneous condition). In Study 2, 48 participants completed the task twice, seven days apart, to evaluate its short-term test-retest reliability. Results do not support the construct validity and the test-retest reliability of switch and mixing costs. The overall higher psychometric properties of the global costs (RT and IES), and primary variables (Hetero RT and IES) suggest that they may be useful measures for clinicians to assess EFs. The latter variables show evidence of convergent validity with standardized measures of EFs and good test-rest reliability (ICC ≥ .68).

Post-exercise cognitive testing to assess persisting alterations in athletes with a history of concussion.

Primary Objective: To determine whether a physical exercise protocol could reveal persistent cognitive alterations in university athletes with a history of concussion (HOC). Thirty-four HOC and 34 controls participated in this study.Research Design: Cross-sectional.Methods and Procedures: The exercise protocol consisted of a 20-min bout on a stationary bike at 80% of the theoretical maximal heart rate. Before and after the exercise, participants performed a computerized switch task designed specifically to recruit executive functions. Group × Condition (pre- and post-exercise) repeated measures of ANCOVAs for accuracy, reaction time, and inverse efficiency score on the switch task were conducted. Chi-square tests were run to determine if the proportion of HOC and controls who underperformed (at least 2SD lower than the control group's average score) at rest and post-exercise were similar. Whilst no interaction or main effects were found with ANCOVAs, significantly more HOC athletes (21%) underperformed following exercise than at rest (3%) on the switch task, p = .02. The current results indicate that an acute bout of exercise can reveal persistent alterations that are not present at rest in the protracted phase of concussion. They also highlight the importance of considering inter-individual differences in recovery trajectories.

Practice effect associated with the serial administration of the switch task and its implications in the assessment of sports-related concussion.

In the context of return to play assessment following a sports concussion, athletes may have to complete a cognitive task several times within days. The current longitudinal study aimed to examine the practice effect associated with the serial administration of the switch task. We hypothesized that the practice effect would be the greatest between the first and second assessments and that a plateau would be obtained by the third assessment. Forty healthy university students completed the switch task four times at an interval of 48-hour, with half of them doing version A on all visits (AA group), while the others alternated between A and B every other assessment (AB group). For response accuracy, performance generally improved from V1 to V2, and from V2 to V3 (ps ≤.001), irrespective of group. For reaction time, a significant interaction of Visit × Group was observed. Specifically, AA group performance improved from V1 to V2, and from V2 to V3, while the AB group only improved from V2 to V3 (ps ≤.01). Performance improved over the first three assessments and stabilized with no statistically significant change between the third and fourth testing sessions. Although the use of an alternative version has helped reduce the practice effect, it did not help in eliminating it. The current results highlight the need for further examination of the practice effect and its implication in clinical decision-making. Clinicians working in the sports concussion field must take the practice effect into account when they use the switch task for serial testing.

Congenital Deafness Leads to Altered Overt Oculomotor Behaviors.

The human brain is highly cross-modal, and sensory information may affect a wide range of behaviors. In particular, there is evidence that auditory functions are implicated in oculomotor behaviors. Considering this apparent auditory-oculomotor link, one might wonder how the loss of auditory input from birth might have an influence on these motor behaviors. Eye movement tracking enables to extract several components, including saccades and smooth pursuit. One study suggested that deafness can alter saccades processing. Oculomotor behaviors have not been examined further in the deaf. The main goal of this study was to examine smooth pursuit following deafness. A pursuit task paradigm was used in this experiment. Participants were instructed to move their eyes to follow a target as it moved. The target movements have a possibility of four different trajectories (horizontal, vertical, elliptic clockwise, and elliptic counter-clockwise). Results indicate a significant reduction in the ability to track a target in both elliptical conditions showing that more complex motion processing differs in deaf individuals. The data also revealed significantly more saccades per trial in the vertical, anti-clockwise, and, to a lesser extent, the clockwise elliptic condition. This suggests that auditory deprivation from birth leads to altered overt oculomotor behaviors.

Clinically Historical and Prospective Associations Between Learning Disorders and Concussion in Young Adult Athletes.

Background. Athletes with specific learning disorder (LD) tend to score lower on neuropsychological tests and are at increased risk of personal injury than their counterparts without such disorders. Using a retrospective historical and prospective design, we examined whether adult athletes with LD, the most prevalent of neurodevelopmental disorders, experience greater chances of past and future concussions than their counterparts without LD. We expected to find that young athletes with LD would show greater risk of past (historical) and future (prospective) cerebral concussions. Methods. Participants (95 men and 53 women aged 18 to 25 years) were recruited from university sports teams and followed during an entire season. Of these, 38 participants had a history of LD and 101 had a history of at least 1 concussion (72 males, 29 females) at the preseason baseline. One-third experienced a new concussion. Data analytic procedures include inferential cross-tabulations. Results. Athletes with LD were twice more likely to have a concussion history at baseline and to have a history of multiple concussions than athletes without LD; 95% CI = [0.86, 4.92] and [0.77, 3.40], respectively. Athletes with LD were twice more likely to incur a new concussion than those without LD; 95% CI = [0.86, 4.92]. Conclusions. Adult athletes with LD experience greater chances of previous and future concussions compared with counterparts without LD. Preventive practices regarding individuals with neurodevelopmental disorders may not only prevent the biopsychosocial consequences of brain trauma for the individual, but also represent a cost-effective public health measure.

Sensitivity of the Cogstate Test Battery for Detecting Prolonged Cognitive Alterations Stemming From Sport-Related Concussions.

OBJECTIVE: To determine if the Cogstate test battery contains the requisite sensitivity to detect prolonged cognitive alterations. METHODS: One hundred twenty collegiate athletes (71 with a history of concussion; 49 controls) completed the Cogstate test battery, to which we added a 2-back condition. In addition to the Cogstate clinical (transformed variables), we analyzed the raw data. RESULTS: The clinical variables failed to reveal any group differences. Further, although the raw data failed to reveal group differences for tasks measuring lower-level cognition, group differences were observed for accuracy on the 1- and 2-back tasks, which require multiple aspects of higher cognition. The overall classification accuracy was higher using the raw data than the clinical variables. The combined sensitivity of the 1- and 2-back task was moderate and specificity was high. CONCLUSIONS: These results suggest that using the raw scores over clinical variables increases the sensitivity of the test battery. Moreover, these results add another piece of evidence suggesting that concussive injuries are associated with subtle long-term alterations in aspects of higher cognition. Importantly, these deficits would have gone unobserved if we had relied solely on automated clinical variables. The current results further our scientific understanding of concussion and may be used to advance clinical practices.

Sensitivity to sounds in sport-related concussed athletes: a new clinical presentation of hyperacusis.

Sensitivity to sounds is one frequent symptom of a sport-related concussion, but its assessment rarely goes beyond a single question. Here we examined sensitivity to sounds using psychoacoustic and psychometric outcomes in athletes beyond the acute phase of injury. Fifty-eight college athletes with normal hearing who either had incurred one or more sport-related concussions (N = 28) or who had never suffered head injury (N = 30) participated. Results indicated that the Concussed group scored higher on the Hyperacusis questionnaire and displayed greater sensitivity to sounds in psychoacoustic tasks compared to the Control group. However, further analyses that separated the Concussed group in subgroups with Sound sensitivity symptom (N = 14) and Without sound sensitivity symptom (N = 14) revealed that athletes with the sound complaint were the ones responsible for the effect: Concussed athletes with self-reported sound sensitivity had lower Loudness Discomfort Thresholds (LDLs), higher Depression and Hyperacusis scores, and shifted loudness growth functions compared to the other subgroup. A simple mediation model disclosed that LDLs exert their influence both directly on Hyperacusis scores as well as indirectly via depressive symptoms. We thus report a new clinical presentation of hyperacusis and discuss possible mechanisms by which it could arise from concussion.

The long-term outcomes of sport-related concussion in pediatric populations.

Although the field of concussion research is rapidly growing, the majority of research has focused on injured adults, with children being an often-neglected population. Traumatic brain injury is a leading cause of death and disability in children, with over 1.5 million cases being treated in North America annually. Approximately 75% of these injuries are classified as a concussion. Further, children are disproportionately affected by sports-related injuries, with 65% of all pediatric concussions occurring during sport and recreation. Therefore, understanding the outcomes of pediatric sportrelated concussion is of great importance, particularly given the vulnerability of the developing brain. The purpose of this review is to provide an up-to-date understanding of the outcomes of pediatric sport-related concussion from a data-driven perspective, focusing heavily on experimental studies.

Long-term cognitive outcomes in male and female athletes following sport-related concussions.

Despite concussion being a serious public health concern and the increasing participation of female athletes in sport, the comparative long-term outcomes of male and female athletes are poorly understood, potentially limiting the scientific understanding and clinical management of these injuries. We examined whether sex influences the long-term cognitive outcomes in athletes with a history of concussion (HOC; 6+ months from injury). Accordingly, 196 asymptomatic student-athletes participated in the study (98 with a HOC; 98 matched controls). The sample included both male (n = 98) and female athletes (n = 98). Participants completed the Cogstate brief battery, to which we added a 2-Back condition to increase cognitive load. As predicted, the results revealed sex differences on the N-back Task, a measure of executive functions, with female athletes having a HOC responding significantly more slowly than their male counterparts on the 2-Back condition (p = 0.02). Moreover, irrespective of sex, athletes with a HOC were slower and less accurate relative to controls on the N-back Task (p = 0.01). Analyses failed to reveal any significant sex or group difference on tasks that measure lower-level cognition (ps > 0.05). The current results reaffirm the presence of subtle, yet long-term alterations in aspects of executive functions following a sport-related concussion. More importantly, our results highlight that female athletes exhibit alterations of greater magnitude than their male counterparts. Therefore, the sex difference observed in the days or weeks following a concussion may persist well into the chronic phase of injury.

Attitudes and lifestyle changes following Jog your Mind: results from a multi-factorial community-based program promoting cognitive vitality among seniors.

This study examined the effects on attitudes and lifestyle behavior of Jog your Mind, a multi-factorial community-based program promoting cognitive vitality among seniors with no known cognitive impairment. A quasi-experimental study was conducted. Twenty-three community organizations were assigned either to the experimental group (offering the program) or to the control group (creating a waiting list). They recruited 294 community-dwelling seniors. The aims of the study were to verify the effects of the program on attitudes and behaviors related to cognitive vitality and to explore its effects on cognitive vitality. Data was collected at baseline and after the program. Regression analyses revealed that, following their participation in the program, experimental group participants reported: (i) in terms of attitudes, having a greater feeling of control concerning their cognitive capacities, (ii) in terms of behaviors, using significantly more memory strategies and practicing more physical activity and stimulating activities than control group participants. However, the program had no significant effects on measures of cognitive vitality. This study supports the fact that a multi-factorial community-based program can have significant effects on seniors' attitudes and lifestyle behaviors related to cognitive vitality but at short term, no effects on cognitive vitality it-self were found.

The independent influence of concussive and sub-concussive impacts on soccer players' neurophysiological and neuropsychological function.

Accumulating research demonstrates that repetitive sub-concussive impacts can alter the structure, function and connectivity of the brain. However, the functional significance of these alterations as well as the independent contribution of concussive and sub-concussive impacts to neurophysiological and neuropsychological health are unclear. Accordingly, we compared the neurophysiological and neuropsychological function of contact athletes with (concussion group) and without (sub-concussion group) a history of concussion, to non-contact athletes. We evaluated event-related brain potentials (ERPs) elicited during an oddball task and performance on a targeted battery of neuropsychological tasks. Athletes in the sub-concussion and concussion groups exhibited similar amplitude reductions in the ERP indices of attentional resource allocation (P3b) and attentional orienting (P3a) relative to non-contact athletes. However, only athletes in the concussion group exhibited reduced amplitude in the ERP index of perceptual attention (N1). Athletes in the sub-concussion and concussion groups also exhibited deficits in memory recall relative to non-contact athletes, but athletes in the concussion group also exhibited significantly more recall errors than athletes in the sub-concussion group. Additionally, only athletes in the concussion group exhibited response delays during the oddball task. The current findings suggest that sub-concussive impacts are associated with alterations in the neurophysiological and neuropsychological indices of essential cognitive functions, albeit to a lesser degree than the combination of sub-concussive and concussive impacts.

Exercise during pregnancy enhances cerebral maturation in the newborn: A randomized controlled trial.

Accumulating research indicates that the regular practice of physical exercise is beneficial to the human brain. From the improvement of academic achievement in children to the prevention of Alzheimer's disease in the elderly, exercise appears beneficial across the developmental spectrum. Recent work from animal studies also indicates that a pregnant mother can transfer the benefits of exercise during gestation to her offspring's brain. Exercising pregnant rats give birth to pups that have better memory and spatial learning as well as increased synaptic density. To investigate whether this transfer from the pregnant mother to her child also occurs in humans, we conducted a randomized controlled trial (n = 18) and measured the impact of exercise during pregnancy on the neuroelectric response of the neonatal brain with electroencephalography (EEG). Here we show that, compared to the newborns of mothers who were inactive during their pregnancy, the children of exercising pregnant women are born with more mature brains. This was measured with the infant slow positive mismatch response (SPMMR), an electroencephalographic potential known to decrease in amplitude with age. The SPMMR reflects processes associated with brain maturation via its response to sound discrimination and auditory memory. In this study, the children of the mothers who exercised throughout their pregnancy have a smaller SPMMR than the children of mothers who remained sedentary (p = .019). Our results demonstrate the impact regular exercise during pregnancy can have on the development of the human fetal brain.

On the Differentiation of Foveal and Peripheral Early Visual Evoked Potentials.

The C1 is one of the earliest visual evoked potentials observed following the onset of a patterned stimulus. The polarity of its peak is dependent on whether stimuli are presented in the upper or lower regions of the peripheral visual field, but has been argued to be negative for stimuli presented to the fovea. However, there has yet to be a systematic investigation into the extent to which the peripheral C1 (pC1) and foveal C1 (fC1) can be differentiated on the basis of response characteristics to different stimuli. The current study employed checkerboard patterns (Exp 1) and sinusoidal gratings of different spatial frequency (Exp 2) presented to the fovea or within one of the four quadrants of the peripheral visual field. The checkerboard stimuli yielded a sizable difference in peak component latency, with the fC1 peaking ~32 ms after the pC1. Further, the pC1 showed a band-pass response magnitude profile that peaked at 4 cycles per degree (cpd), whereas the fC1 was high-pass for spatial frequency, with a cut-off around 4 cpd. Finally, the scalp topographies of the pC1 and fC1 in both experiments differed greatly, with the fC1 being more posterior than the pC1. The results reported here call into question recent attempts to characterize general C1 processes without regard to whether stimuli are placed in the fovea or in the periphery.

Persisting Effects of Concussion on Heart Rate Variability during Physical Exertion.

The purpose of this study was to evaluate cardiac autonomic modulation in university athletes during the post-acute to late phase (mean, 95 days ±63) of injury at rest and during physical exertion. We also sought to evaluate the effect of time since injury and number of injuries on heart rate variability (HRV). We hypothesized that physical exertion would reveal persisting modifications in HRV following a concussion. We included, in a cross-sectional design, athletes who sustained a concussion and matched controls. Concussions were identified by a medical doctor using established criteria. Twelve male concussed and 12 control athletes took part in the study. Control participants were teammates who were chosen to match the concussed athletes with regard to their height, weight, education, and age. The beat-to-beat electrocardiogram intervals of the participants were measured at rest and during physical exertion (isometric hand grip contraction; IHGC), which was sustained for 3 minutes at 30% of the participants' maximum. Linear and nonlinear parameters of HRV were calculated. The ratio between low and high frequency (LF/HF) bands was calculated to assess the sympathovagal balance. During the IHGC, but not at rest, concussed athletes presented significantly lower power in HF bands, leading to a significantly higher LF/HF ratio (p ≤ 0.05). Thus, asymptomatic athletes still may exhibit modifications in cardiac autonomic modulation weeks to months following injury. These modifications may only become apparent during physical exertion. Monitoring HRV may aid diagnosis and provide insight about safe return to play.

Neurophysiological correlates of persistent psycho-affective alterations in athletes with a history of concussion.

Understanding the neuropathological underpinnings of sport-related concussion are critical for diagnosis, prognosis, and remediation. Although electro-encephalographic (EEG) methods have proven invaluable for understanding psycho-affective pathologies in various clinical conditions, they have not been used to understand the psycho-affective outcomes of concussive injuries. Accordingly, we evaluated the relation of electroencephalographic (EEG) power in collegiate athletes to psycho-affective measures. We predicted that athletes with a history of concussion would exhibit alterations in frontal EEG asymmetries indicative of increased depression, anxiety and more general mood disturbance. During this cross-sectional study, resting EEG and measures of mood and affect, including the Beck Depression Inventory-II (BDI-II) and Profile of Mood States (POMS) were collected in 81 young-adult male athletes (52 concussion history; 29 controls). All athletes with a history of concussion (9+ months from injury) reported to be symptom free, and all participants were actively taking part in their sport at the time of testing. Compared to control athletes, the athletes with a history of concussion exhibited alterations in frontal-alpha and frontal-beta asymmetry (p's < .05). Correlational analyses revealed that alterations in frontal-alpha asymmetry were related to self-reported depression and anxiety, and alterations in beta-asymmetry were related to self-reported anger/aggression, but these relations were only significant for athletes with a history of concussion. The current study suggests that athletes with a history of concussion who made a complete return to play and reported to be asymptomatic on a commonly used symptom checklist may still exhibit neural activity associated with increased levels of depression, anxiety and anger/hostility. The current results reinforce the clinical necessity for long-term evaluations of athletes irrespective of apparent symptom resolution, and suggest that EEG may serve as a sensitive tool to identify and track concussion-related alterations in psycho-affective health before they manifest as clinical disorders.

The persistent influence of concussion on attention, executive control and neuroelectric function in preadolescent children.

The aim of this investigation was to examine the influence of pediatric sport-related concussion on brain and cognitive function. To do so, we used a between-participants design, measures of executive control, and event-related potentials (ERPs). The findings demonstrate that children with a history of concussion exhibit behavioral deficits in attention, working memory and impulse control, as well as neuroelectric alterations in ERP indices of visual attention (N1), conflict resolution (N2) and attentional resource allocation (P3). Furthermore, the age at injury related to the magnitude of several concussion-related deficits. Accordingly, a single sports-related concussive incident during childhood (m=2.1years prior to testing) may lead to subtle, yet pervasive alterations in the behavioral and neural indices of attention and executive control, and age at injury may moderate injury outcomes.