Computerised cognitive assessment of concussed Australian Rules footballers

Neurocognitive Intraindividual Variability in Veterans with Mild Traumatic Brain Injury History and Posttraumatic Stress Disorder

OBJECTIVE

Veterans with a history of blast-related mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) may be at risk for greater cognitive concerns and worse functional outcomes compared to those with either condition in isolation. However, traditional neuropsychological assessment approaches have yielded equivocal results in these populations. The present study examined an alternative method for detecting subtle cognitive inefficiencies: neurocognitive intraindividual variability (IIV), a measure of within-person performance consistency.

METHOD

Participants were 79 male Veterans with a history of blast-related mTBI and current PTSD (mTBI/PTSD group; n = 54) or neither diagnosis (controls; n = 25). Mean T-scores and IIV scores were calculated from neuropsychological measures of attention and speed of information processing (A/SoP) as well as executive functioning (EF).

RESULTS

Global IIV was significantly higher in the mTBI/PTSD group compared to controls (p = .047, Cohen's d = 0.49). At the domain level, larger effect sizes were observed for EF IIV (Cohen's d = 0.46) compared to A/SoP IIV (d = 0.32), although neither were statistically significant. Within the mTBI/PTSD group, higher Global IIV was associated with worse self-reported executive dysfunction, psychological quality of life, and cognitive post-concussive symptoms; at the domain level, these clinical outcomes were generally associated with greater A/SoP IIV (but not EF IIV).

CONCLUSION

Findings extend previous investigations of neurocognitive IIV in individuals with a history of mTBI across PTSD status. Among Veterans with a history of mTBI and comorbid PTSD, neurocognitive variability may be a better indicator of self-reported cognitive inefficiencies and Veteran experience of daily cognitive functioning than mean neuropsychological performances.

Engagement in online cognitive testing with the Cogstate brief battery among a multinational cohort of people with focal epilepsy

OBJECTIVE

The Human Epilepsy Project (HEP) is a large multinational cohort study of people with newly diagnosed and treated focal epilepsy. HEP utilized the Cogstate Brief Battery (CBB) as a self-directed online assessment to examine cognitive outcomes in study participants. The CBB has previously been validated in healthy individuals and people with various brain disorders, but its use in adults participating in HEP has not been assessed. In this study, we describe how the CBB was used in the HEP cohort and assess factors associated with test completion among study participants.

METHODS

Enrollment data for HEP included 408 participants with comprehensive enrollment records, of whom 249 completed CBB assessments. HEP enrolled cognitively normal-range participants between the ages of 12 and 60 from June 29, 2012, to November 7, 2017, with newly diagnosed focal epilepsy and within 4 months of initial treatment. Baseline participant characteristics were analyzed, including demographics, pre-treatment seizure histories, MRI abnormalities, and the presence of any learning difficulties while in school, including formal learning disability diagnoses, repeated grades, and remediation. HEP participant characteristics for those who completed CBB testing were compared to those who did not using multiple logistic regression.

RESULTS

The analysis of HEP participants who completed CBB testing showed that, after controlling for other factors, male participants were more likely to engage in testing (OR 2.14, 95 % CI 1.29 to 3.5, p < 0.01), Black subjects were less likely (OR 0.45, 95 % CI 0.22 to 0.9, p = 0.02), primary English speakers were more likely (OR 3.1, 95 % CI 1.21 to 7.96, p = 0.02), and those with a history of learning challenges were less likely (OR 0.69, 95 % CI 0.49 to 0.97, p = 0.03). There were no significant associations between completing CBB testing and age, employment (employed or student vs not), education (higher education vs not), diagnostic delay, pre-diagnostic seizure burden, or initial seizure semiology (motor vs non-motor).

SIGNIFICANCE

The findings from this study highlight factors associated with the application of remote and unsupervised assessments of cognition in a prospective cohort of adults with focal epilepsy. These factors can be considered when interpreting performance on the CBB in HEP, as well as assisting the design of future studies that use similar approaches.

A review of methods for assessment of cognitive function in high-altitude hypoxic environments

Hypoxic environments like those present at high altitudes may negatively affect brain function. Varying levels of hypoxia, whether acute or chronic, are previously shown to impair cognitive function in humans. Assessment and prevention of such cognitive impairment require detection of cognitive changes and impairment using specific cognitive function assessment tools. This paper summarizes the findings of previous research, outlines the methods for cognitive function assessment used at a high altitude, elaborates the need to develop standardized and systematic cognitive function assessment tools for high-altitude hypoxia environments.

Psychometric Properties of Computerized Cognitive Tools and Standard Neuropsychological Tests Used to Assess Sport Concussion: A Systematic Review

Athletic programs are more frequently turning to computerized cognitive tools in order to increase efficiencies in concussion assessment. However, assessment using a traditional neuropsychological test battery may provide a more comprehensive and individualized evaluation. Our goal was to inform sport clinicians of the best practices for concussion assessment through a systematic literature review describing the psychometric properties of standard neuropsychological tests and computerized tools. We conducted our search in relevant databases including Ovid Medline, Web of Science, PsycINFO, and Scopus. Journal articles were included if they evaluated psychometric properties (e.g., reliability, sensitivity) of a cognitive assessment within pure athlete samples (up to 30 days post-injury). Searches yielded 4,758 unique results. Ultimately, 103 articles met inclusion criteria, all of which focused on adolescent or young adult participants. Test-retest reliability estimates ranged from .14 to .93 for computerized tools and .02 to .95 for standard neuropsychological tests, with strongest correlations on processing speed tasks for both modalities, although processing speed tasks were most susceptible to practice effects. Reliability was improved with a 2-factor model (processing speed and memory) and by aggregating multiple baseline exams, yet remained below acceptable limits for some studies. Sensitivity to decreased cognitive performance within 72 h of injury ranged from 45%-93% for computerized tools and 18%-80% for standard neuropsychological test batteries. The method for classifying cognitive decline (normative comparison, reliable change indices, regression-based methods) affected sensitivity estimates. Combining computerized tools and standard neuropsychological tests with the strongest psychometric performance provides the greatest value in clinical assessment. To this end, future studies should evaluate the efficacy of hybrid test batteries comprised of top-performing measures from both modalities.

RETRACTED - Intra-individual Cognitive Variability: An Examination of ANAM4 TBI-MIL Simple Reaction Time Data from Service Members with and without Mild Traumatic Brain Injury

Objectives: The Automated Neuropsychological Assessment Metrics 4 TBI-MIL (ANAM4) is a computerized cognitive test often used in post-concussion assessments with U.S. service members (SMs). Existing evidence, however, remains mixed regarding ANAM4's ability to identify cognitive issues following mild traumatic brain injury (mTBI). Studies typically examine ANAM4 by comparing mean scores to baseline or normative scores. A more fine-grained approach involves examining inconsistency within an individual's performance. Methods: Data from a sample of 231 were healthy control SMs and 100 SMs within 7 days of mTBI who took the ANAM4 were included in analyses. We examine each individual's performance on a simple reaction time (SRT) subtest that is administered at the beginning (SRT1) and end (SRT2) of the ANAM4 battery, and calculate the standard deviation of difference scores by trial across administrations. Results: Multivariate analysis of variance and univariate analyses revealed group differences across all comparisons (p<.001) with pairwise comparisons revealing higher intra-individual variability and slower raw reaction time for the mTBI group compared with controls. Effect sizes were small though exceeded the recommended minimum practical effect size (ES>0.41). Conclusions: While inconsistencies in performance are often viewed as noise or test error, the results suggest intra-individual cognitive variability may be more sensitive than central tendency measures (i.e., comparison of means) in detecting changes in cognitive function in mTBI. Additionally, the findings highlight the utility of ANAM4's repeating a subtest at two points in a battery to explore within-subject differences in performance. (JINS, 2017, 23, 1-6).

Symptom Provocation Following Post-concussion Computerized Neurocognitive Testing and Its Relationship to Other Clinical Measures of Concussion

OBJECTIVE

The objective of this study was to document the prevalence of post-computerized neurocognitive test (post-CNT) increases in symptoms in athletes with sport-related concussion, and to examine the effect of post-CNT symptom increases on concussion neurocognitive and vestibular/ocular motor clinical outcomes.

METHODS

This was a retrospective analysis of medical records from a concussion specialty clinic. Two hundred and three athletes (M = 16.48 ± 1.97 years; 44% [90/203] female) completed a clinical visit for concussion within 30 days of injury (M = 7.73 ± 5.54 days). Computerized neurocognitive testing (the Immediate Post-concussion Assessment and Cognitive Testing: ImPACT), the Post-Concussion Symptom Scale (PCSS), and the Vestibular Ocular Motor Screening (VOMS) were the main outcome measures for the current study.

RESULTS

Sixty-nine percent (141/203) of the sample did not report significant increases in PCSS scores following post-concussion CNT and were classified into a No Provocation (NO PROV) group. Thirty-one percent (62/203) of participants did report a significant increase in symptoms following post-concussion CNT and were classified into a Provocation (PROV) group. Neurocognitive performance was similar between groups. However, the PROV group reported significantly higher scores on the VOMS symptom items than the NO PROV group.

CONCLUSIONS

The majority of adolescent athletes can complete a post-concussion CNT without experiencing significant increases in concussion symptoms. Individuals that report symptom increases from completing a post-concussion CNT are more likely to exhibit increased vestibular/ocular motor symptoms. These findings underscore the relationship between the clinical findings from both CNT and vestibular/ocular motor measures following concussion.

The relationship between spatiotemporal gait parameters and cognitive function in healthy adults: protocol for a cross-sectional study

BACKGROUND

Motor dysfunctions, such as slower walking speed, precede the occurrence of dementia and mild cognitive impairment, suggesting that walking parameters are effective biomarkers for detecting early sub-clinical cognitive risk. It is often also concurrent with self-complained cognitive dysfunction, called motoric cognitive risk (MCR) syndrome. Our preliminary study found several walking parameters, obtained by a three-dimensional motion capture system, to be correlated with computer-based assessments of various cognitive function modalities, although the sample size was small. The Cognitive-Gait (CoGait) Database Project, described in the current protocol, aims to establish a database of multi-dimensional walking and cognitive performance data, collected from a large sample of healthy participants, crucial for detecting early sub-clinical cognitive risk.

METHODS

We will recruit healthy volunteers, 20 years or older, without any neurological musculoskeletal or psychiatric disorders. The estimated sample size is 450 participants, including a 10% attrition rate. Using computer-based cognitive assessments, participants will perform six tasks: (i) the simple reaction time task, (ii) Go/No-Go task, (iii) Stroop Color-Word Test, (iv) N-back test, (v) Trail Making Test, and (vi) digit span test. We will also conduct paper-based cognitive assessments such as the Mini-Mental State Examination, Montreal Cognitive Assessment, and the Geriatric Depression Scale-15 for assessing MCR. Gait will be measured through joint kinematics and global positioning in participants' lower legs while walking at a comfortable and faster pace, using pants with an inertial measurement unit-based three-dimensional motion capture system. Finally, we will establish a prediction model for various cognitive performance modalities based on walking performance.

DISCUSSION

This will be the first study to reveal the relationship between walking and cognitive performance using multi-dimensional data collected from a large sample of healthy adults, from the general population. Despite certain methodological limitations such as the accuracy of measurements, the CoGait database is expected to be the standard value for both walking and cognitive functions, supporting the evaluation of psychomotor function in early sub-clinical cognitive risk identification, including motoric-cognitive risk syndrome.

The Neurological Consequences of Engaging in Australian Collision Sports

Collision sports are an integral part of Australian culture. The most common collision sports in Australia are Australian rules football, rugby union, and rugby league. Each of these sports often results in participants sustaining mild brain traumas, such as concussive and subconcussive injuries. However, the majority of previous studies and reviews pertaining to the neurological implications of sustaining mild brain traumas, while engaging in collision sports, have focused on those popular in North America and Europe. As part of this 2020 International Neurotrauma Symposium special issue, which highlights Australian neurotrauma research, this article will therefore review the burden of mild brain traumas in Australian collision sports athletes. Specifically, this review will first provide an overview of the consequences of mild brain trauma in Australian collision sports, followed by a summary of the previous studies that have investigated neurocognition, ocular motor function, neuroimaging, and fluid biomarkers, as well as neuropathological outcomes in Australian collision sports athletes. A review of the literature indicates that although Australians have contributed to the field, several knowledge gaps and limitations currently exist. These include important questions related to sex differences, the identification and implementation of blood and imaging biomarkers, the need for consistent study designs and common data elements, as well as more multi-modal studies. We conclude that although Australia has had an active history of investigating the neurological impact of collision sports participation, further research is clearly needed to better understand these consequences in Australian athletes and how they can be mitigated.

Health-Related Quality of Life: Longitudinal Analysis From the Time of Breast Biopsy Into the Post-treatment Period

Background: The physical, psychological, social, and spiritual quality of life (QoL) may be affected by breast cancer diagnosis and treatment, with mixed findings for psychological quality of life and cognitive ability performance. The present study aimed to evaluate QoL in women over 1 year from biopsy for a breast abnormality. Methods: Self-reported measures of physical, psychological, social, and spiritual QoL were obtained after biopsy results but prior to treatment initiation (baseline), 4 and 12 months later. CogState computerized neuropsychological screening battery also provided an evaluation of psychological QoL. Three groups of women including those with benign biopsy results, those with malignancy treated with chemotherapy, and those with malignancy not treated with chemotherapy were compared at 4 and 12 months after adjusting for baseline to isolate the effects of treatment. Additional covariates included are age, level of education, and income. Results: Benign biopsy results group included 72 women, whereas malignancy was found in 87 women of whom 33 were treated with chemotherapy and 54 without chemotherapy. At the time of diagnosis, women with cancer had worse psychological and social QoL but better spiritual QoL than those with benign biopsy results. Only CogState monitoring accuracy was worse for women with cancer compared with the controls at the time of biopsy results. After adjusting for QoL at baseline, women treated for cancer had worse physical and social QoL at 4 and 12 months later. Psychological well-being was worse for women with cancer at 4th month but improved at 1 year. No differences in cognition were found at 4 and 12 months when adjusted for baseline cognition and covariates. Discussion: Breast cancer is a traumatic life event for women, affecting psychological and social QoL domains, yet increasing spiritual QoL. Later, cancer treatment worsens physical, psychological, and social QoL compared with those without cancer. Conclusions: These findings suggest that interventions to improve psychological QoL may be especially important at the time of cancer diagnosis, while interventions to improve physical well-being are the most needed during and following cancer treatment. Support to improve social QoL is needed from the time of diagnosis into post-treatment survivorship.

A Battery of Easily Accessible, Simple Tools for the Assessment of Concussion in Children

OBJECTIVE

To determine whether a non-proprietary, novel testing battery can identify recently concussed children within 8 weeks of injury.

STUDY DESIGN

In total, 568 clinic outpatients aged 10-18 years were sorted into 3 groups: 316 had never been concussed, 162 had ever been concussed before 8 weeks earlier, and 90 had been recently concussed within 8 weeks. At initial and any subsequent visits, a neurologic examination and 4 procedures were performed: Stick Drop, Wall Ball, Sharpened Modified Romberg (SMR), and Animal Naming. Analysis included inter-group and intra-person performance differences using a series of t tests on the Stick Drop, Wall Ball, SMR, and Animal Naming.

RESULTS

The recently concussed group performed worse (P < .01 for all) on Stick Drop, total Wall Ball bounces and drops, and SMR compared with never-concussed and ever-concussed groups. This effect for Stick Drop, SMR, and Wall Ball but not Animal Naming persisted beyond the 4 weeks commonly stated to define recovery. Of 59 recently concussed subjects who returned for ≥1 visit, there were improvements in Stick Drop average (P = .004) and maxima (P = .02) as well as SMR (P = .01) but not Animal Naming between initial and subsequent visits.

CONCLUSIONS

This novel, rapid testing battery distinguished groups of children ages 10-18 years who had and had not experienced a recent concussion. A view that physical concussion symptoms resolve within a month of injury may be incomplete. Deployment of this readily available, inexpensive and non-proprietary battery should be compared with other tools and studied further in serial assessments.

A Comparison of Electronic and Paper Versions of the Montreal Cognitive Assessment

OBJECTIVE

The objective of this study was to investigate older adults' performance on the paper and electronic Montreal Cognitive Assessment (eMoCA).

DESIGN

Repeated measures and correlational design.

PARTICIPANTS

A convenience sample of 40 adults over 65 years of age living in the community.

INTERVENTIONS

Participants completed the eMoCA and paper Montreal Cognitive Assessment (MoCA) in a randomized order during 1 session. Participants reported their touchscreen experience and comfort and indicated their modality preferences.

MAIN OUTCOME MEASURES

The primary outcome measures were paper MoCA and eMoCA total and subscale scores. Secondary outcome measures included participants' reported touchscreen experience and comfort, as well as post-administration preferences.

RESULTS

A moderate statistically significant correlation was found between eMoCA and paper MoCA performance across all participants. Analysis comparing first administration modality only (eMoCA vs. paper MoCA) found no statistically significant difference in total scores; however, there was a statistically significant difference for the visuospatial/executive subscale, which required physical interaction with paper or the tablet. For this subscale, participants scored lower on the eMoCA versus paper MoCA. There was a statistically significant correlation between experience with touchscreen devices and performance on the eMoCA, but not between modality preference and performance.

CONCLUSION

Modality of administration can affect performance on cognitive assessments. Clinicians should consider individuals' level of touchscreen experience before selecting administration modality.

Development of a new virtual reality test of cognition: assessing the test-retest reliability, convergent and ecological validity of CONVIRT

Background

Technological advances provide an opportunity to refine tools that assess central nervous system performance. This study aimed to assess the test-retest reliability and convergent and ecological validity of a newly developed, virtual-reality, concussion assessment tool, ‘CONVIRT’, which uses eye-tracking technology to assess visual processing speed, and manual reaction time (pushing a button on a riding crop) to assess attention and decision-making. CONVIRT was developed for horse jockeys, as of all sportspersons, they are most at risk of concussion.

Methods

Participants (N = 165), were assessed with CONVIRT, which uses virtual reality to give the user the experience of riding a horse during a horserace. Participants were also assessed with standard Cogstate computer-based concussion measures in-between two completions of the CONVIRT battery. The physiological arousal induced by the test batteries were assessed via measures of heart rate and heart rate variability (LF/HF ratio).

Results

Satisfactory test-retest reliability and convergent validity with Cogstate attention and decision-making subtests and divergent validity in visual processing speed measures were observed. CONVIRT also increased heart rate and LF/HF ratio, which may better approximate participant arousal levels in their workplace.

Conclusions

CONVIRT may be a reliable and valid tool to assess elements of cognition and CNS disruption. The increased ecological validity may also mean better informed ‘return-to-play’ decisions and stronger industry acceptance due to the real-world meaningfulness of the assessment. However, before this can be achieved, the sensitivity of the CONVIRT battery needs to be demonstrated.

The Influence of Heat Acclimation and Hypohydration on Post-Weight-Loss Exercise Performance

PURPOSE

To examine the influence of fluid intake on heat acclimation and the subsequent effects on exercise performance following acute hypohydration.

METHODS

Participants were randomly assigned to 1 of 2 groups, either able to consume water ad libitum (n = 10; age 23 [3] y, height 1.81 [0.09] m, body mass 87 [13] kg; HAW) or not allowed fluid (n = 10; age 26 [5] y, height 1.76 [0.05] m, body mass 79 [10] kg; HANW) throughout 12 × 1.5-h passive heat-acclimation sessions. Experimental trials were completed on 2 occasions before (2 baseline trials) and 1 following the heat-acclimation sessions. These sessions involved 3 h of passive heating (45°C, 38% relative humidity) to induce hypohydration followed by 3 h of ad libitum food and fluid intake after which participants performed a repeat sled-push test to assess physical performance. Urine and blood samples were collected before, immediately, and 3 h following hypohydration to assess hydration status. Mood was also assessed at the same time points.

RESULTS

No meaningful differences in physiological or performance variables were observed between HANW and HAW at any time point. Using pooled data, mean sprint speed was significantly (P < .001) faster following heat acclimation (4.6 [0.7] s compared with 5.1 [0.8] s). Furthermore, heat acclimation appeared to improve mood following hypohydration.

CONCLUSIONS

Results suggest that passive heat-acclimation protocols may be effective at improving short-duration repeat-effort performance following acute hypohydration.

Testing the hybrid battery approach to evaluating sports-related concussion in the National Hockey League: A factor analytic study

Objective: There has been an increased interest in the use of "Hybrid" neuropsychological test batteries to evaluate neurocognitive functioning prior to and following sports-related concussion. Typically, these test batteries include a combination of traditional "paper and pencil" (P&P) and computerized measures. The National Hockey League (NHL) employs a Hybrid approach consisting of ImPACT and a brief battery of P&P measures. The purpose of this paper was to examine the NHL's Hybrid model by means of factor analytic techniques in order to determine the extent to which the measures included in the battery are independent of each other or share common variance.Method: Principal components analyses with promax rotations were conducted on the P&P measures alone and when combined with ImPACT. A total of 360 recently concussed NHL players underwent testing using the combined hybrid battery.Results: A principal components analysis with promax rotation of the combined hybrid battery yielded 5 factors (Verbal Learning/Memory, Visual Learning/Memory, Processing Speed/Executive Functioning, Cued/Recognition Memory and Reaction Time/Speed). The factors appear to be relatively independent of each other with the P&P measures comprising the Verbal Learning/Memory, Visual Learning/Memory, and Processing Speed/Executive Functioning and ImPACT loading on the Cued/Recognition Memory and Reaction Time/Speed factors.Conclusions: These data provide support for the Hybrid model with evidence that the P&P measures and ImPACT do not measure the same domains of cognitive functioning. The clinical implications of the findings are discussed in detail.

Cervicovestibular rehabilitation in adult with mild traumatic brain injury: a randomised controlled trial protocol

Background

Mild traumatic brain injury (mTBI) is an acknowledged public health problem. Up to 25% of adult with mTBI present persistent symptoms. Headache, dizziness, nausea and neck pain are the most commonly reported symptoms and are frequently associated with cervical spine and vestibular impairments. The most recent international consensus statement (2017 Berlin consensus) recommends the addition of an individualized rehabilitation approach for mTBI with persistent symptoms. The addition of an individualized rehabilitation approach including the evaluation and treatment of cervical and vestibular impairments leading to symptoms such as neck pain, headache and dizziness is, however, recommended based only on limited scientific evidence. The benefit of such intervention should therefore be further investigated.

Objective

To compare the addition of a 6-week individualized cervicovestibular rehabilitation program to a conventional approach of gradual sub-threshold physical activation (SPA) alone in adults with persistent headache, neck pain and/or dizziness-related following a mTBI on the severity of symptoms and on other indicators of clinical recovery. We hypothesize that such a program will improve all outcomes faster than a conventional approach (between-group differences at 6-week and 12-week).

Methods

In this single-blind, parallel-group randomized controlled trial, 46 adults with subacute (3 to12 weeks post-injury) persistent mTBI symptoms will be randomly assigned to: 1) a 6-week SPA program or 2) SPA combined with a cervicovestibular rehabilitation program. The cervicovestibular rehabilitation program will include education, cervical spine manual therapy and exercises, vestibular rehabilitation and home exercises. All participants will take part in 4 evaluation sessions (baseline, week 6, 12 and 26) performed by a blinded evaluator. The primary outcome will be the Post-Concussion Symptoms Scale. The secondary outcomes will be time to clearance to return to function, number of recurrent episodes, Global Rating of Change, Numerical Pain Rating Scale, Neck Disability Index, Headache Disability Inventory and Dizziness Handicap Inventory. A 2-way ANOVA and an intention-to-treat analysis will be used.

Discussion

Controlled trials are needed to determine the best rehabilitation approach for mTBI with persistent symptoms such as neck pain, headache and dizziness. This RCT will be crucial to guide future clinical management recommendations.

Trial registration

ClinicalTrials.gov Identifier - NCT03677661, Registered on September, 15th 2018.

Gender differences in nonlinear motor performance following concussion

PURPOSE

To quantify differences in nonlinear aspects of performance on a seated visual-motor tracking task between clinically asymptomatic males and females with and without a self-reported mild traumatic brain injury history.

METHODS

Seventy-three individuals with a self-reported concussion history (age: 21.40 ± 2.25 years, mean ± SD) and 75 without completed the visual-motor tracking task (age: 21.50 ± 2.00 years). Participants pressed an index finger against a force sensor, tracing a line across a computer screen (visual-motor tracking). The produced signal's root-mean-square error (RMSE), sample entropy (SampEn, a measure of regularity), and average power (AvP) between 0 and 12 Hz were calculated.

RESULTS

Males with a history of 0 or 1 concussion had greater RMSE (worse performance) than females with 0 (p < 0.0001) and 1 concussion (p = 0.052). Additionally, females with 2+ concussions exhibited lower SampEn than females with no history (p = 0.001) or a history of 1 concussion (p = 0.026). Finally, females with 2+ concussions had lower 8-12 Hz AvP than males with 2+ concussions (p = 0.031). Few differences were observed in the male participants.

CONCLUSION

Females with a self-reported history of multiple concussions exhibited lower SampEn in the visual-motor tracking-task force output structure as compared to those with no reported history of concussion and their male counterparts. Lower SampEn and lower power between 8 and 12 Hz indicated persistent impairment in visual processing and feed-forward or predictive motor control systems.

A systematic review of acute concussion assessment selection in research

Background: Several organisations developed guidelines and assessments for aiding in the diagnosis of concussions. The growing number of concussion assessments increases the difficulty for researchers and clinicians to determine the best method of concussion diagnosis. Purpose: To systematically review the current assessments selected for acute sports-related concussion. Methods: Academic Search Premier, CINHAL, MEDLINE, PsycINFO and SPORTDiscus were searched. English-language, peer-review published studies of acute (<72 h) concussion assessments were included. Results: A total of 31 studies met inclusion criteria (of 291 evaluated); 27 studies provided sufficient information to be included in the descriptive statistics of the assessments. Six of these assessments were used in at least three studies. Only 12 percent of the population studied was female. The age range for these assessments was 9-67 years, although most participants ranged in age between 18 and 35 years. Conclusion: There is a need for a 'gold' standard concussion assessment to enable consistency across research and clinical outcomes. We found a large discrepancy between the number of males and females assessed, suggesting that future studies are needed to determine if these current assessments identify concussion signs and symptoms unique to females. Further studies are needed to determine which assessments are appropriate and valid for youth athletes.

Exploring changes in processing speed and intraindividual variability in youth following sports-related concussion

Background

Concussion represents a growing concern in sports participation for adults and youth alike. Studies exploring the neurocognitive sequelae of concussion, such as speed of processing typically compare mean reaction time scores to a control group. Intraindividual variability measures the consistency of reaction times between trials and has been previously explored in adults post-concussion. Some adult studies show increased variability following injury. Developmentally youth show higher intraindividual variability than adults, which may put them at higher risk of increased intraindividual variability change post-concussion. Exploring intraindividual variability may provide additional insight into fluctuating performance reported following injury. Despite preliminary findings of slowed reaction time in youth, a pre-/post-concussion comparison of intraindividual variability of reaction time has not been explored.

Objective

To describe and compare pre- and post-concussion measures of processing speed and intraindividual variability in youth.

Methods

A pre-/post-concussion design was used to compare mean reaction time and the coefficient of variation before and after sports-related concussion in 18 youth athletes aged 10–14 years using verbal and nonverbal working memory tasks. Pre-/post-concussion reaction time and coefficient of variation were compared using t-tests.

Results

The coefficient of variation for nonverbal working memory was significantly higher following concussion, but no changes in average reaction time were found.

Conclusions

Preliminary findings suggest that average response times are unchanged following concussion, but the fluctuation across response times is more variable during a nonverbal working memory task in youth. Increased variability in speed of reaction times could have implications for safe return to sports and reduced academic performance.

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.

Incidence of Concussion and Head Impacts in Australian Elite-Level Male and Female Cricketers After Head Impact Protocol Modifications

Background:

Concussion in sport is a topic of growing interest in Australia and worldwide. To date, relatively few studies have examined the true incidence of concussion in cricket.

Hypothesis:

Concussion in cricket is more common than current literature suggests.

Study Design:

Descriptive epidemiology study.

Level of Evidence:

Level 4.

Methods:

This is a prospective registry and subsequent analysis of head impacts and concussions in elite-level male and female cricketers in Australia over 2 seasons (2015-2016 and 2016-2017). A total of 172 male and 106 female domestic and international players in 2015-2016 and 179 males and 98 females in 2016-2017 were included.

Results:

There were 92 head impacts (29 concussions) in men’s matches and 15 head impacts (8 concussions) in women’s matches. Match incidence rates per 1000 player days were 7.2 head impacts (2.3 concussions) in elite male cricket and 3.7 head impacts (2.0 concussions) in elite female cricket. This equates to a head impact every 2000 balls and concussion every 9000 balls in male domestic cricket. Concussion rates per 1000 player-match hours were 0.4 for elite males and 0.5 for elite females; 53% of head impacts in females were diagnosed as concussions compared with 32% in males, and 83% of concussions resulted in missing no more than 1 game.

Conclusion:

The rate of concussion in cricket is higher than previously appreciated; however, the majority of patients recovered quickly, and players generally did not miss much playing time as a result. The institution of concussion policies after head impact, including player substitution, appears to have had an effect on increasing reporting of symptoms, resulting in an increase in diagnosis of concussion.

Clinical Relevance:

Concussion in cricket is not as infrequent as previously assumed. Ongoing review of the rules and regulations is required to ensure that protection of player welfare lies in parallel with other sporting codes.

A Comparison of Four Computerized Neurocognitive Assessment Tools to a Traditional Neuropsychological Test Battery in Service Members with and without Mild Traumatic Brain Injury

Objective

Computerized neurocognitive assessment tools (NCATS) are often used as a screening tool to identify cognitive deficits after mild traumatic brain injury (mTBI). However, differing methodology across studies renders it difficult to identify a consensus regarding the validity of NCATs. Thus, studies where multiple NCATs are administered in the same sample using the same methodology are warranted.

Method

We investigated the validity of four NCATs: the ANAM4, CNS-VS, CogState, and ImPACT. Two NCATs were randomly assigned and a battery of traditional neuropsychological (NP) tests administered to healthy control active duty service members (n = 272) and to service members within 7 days of an mTBI (n = 231). Analyses included correlations between NCAT and the NP test scores to investigate convergent and discriminant validity, and regression analyses to identify the unique variance in NCAT and NP scores attributed to group status. Effect sizes (Cohen's f2) were calculated to guide interpretation of data.

Results

Only 37 (0.6%) of the 5,655 correlations calculated between NCATs and NP tests are large (i.e. r ≥ 0.50). The majority of correlations are small (i.e. 0.30 > r ≥ 0.10), with no clear patterns suggestive of convergent or discriminant validity between the NCATs and NP tests. Though there are statistically significant group differences across most NCAT and NP test scores, the unique variance accounted for by group status is minimal (i.e. semipartial R2 ≤ 0.033, 0.024, 0.062, and 0.011 for ANAM4, CNS-VS, CogState, and ImPACT, respectively), with effect sizes indicating small to no meaningful effect.

Conclusion

Though the results are not overly promising for the validity of the four NCATs we investigated, traditional methods of investigating psychometric properties may not be appropriate for computerized tests. We offer several conceptual and methodological considerations for future studies regarding the validity of NCATs.

Intraindividual Cognitive Variability: An Examination of ANAM4 TBI-MIL Simple Reaction Time Data from Service Members with and without Mild Traumatic Brain Injury

OBJECTIVES

The Automated Neuropsychological Assessment Metrics 4 TBI-MIL (ANAM4) is a computerized cognitive test often used in post-concussion assessments with U.S. service members (SMs). However, existing evidence remains mixed regarding ANAM4's ability to identify cognitive issues following mild traumatic brain injury (mTBI). Studies typically examine ANAM4 using standardized scores and/ or comparisons to a baseline. A more fine-grained approach involves examining inconsistency within an individual's performance (i.e., intraindividual variability).

METHODS

Data from 237 healthy control SMs and 105 SMs within seven days of mTBI who took the ANAM4 were included in analyses. Using each individual's raw scores on a simple reaction time (RT) subtest (SRT1) that is repeated at the end of the battery (SRT2), we calculated mean raw RT and the intraindividual standard deviation (ISD) of trial-by-trial RT. Analyses investigated differences between groups in mean RT, RT variability (i.e., ISD), and change in ISD from SRT1 and SRT2.

RESULTS

Using regression residuals to control for demographic variables, analysis of variance, and pairwise comparisons revealed the control group had faster mean RT and smaller ISD compared to the mTBI group. Furthermore, the mTBI group had a significant increase in ISD from SRT1 to SRT2, with effect sizes exceeding the minimum practical effect for comparisons of ISD in SRT2 and change in ISD from SRT1 to SRT2.

CONCLUSIONS

While inconsistencies in performance are often viewed as test error, the results suggest intraindividual cognitive variability may be more sensitive than traditional metrics in detecting changes in cognitive function after mTBI. Additionally, the findings highlight the utility of the ANAM4's repeating a RT subtest at two points in the same session for exploring within-subject differences in performance variability. (JINS, 2018, 24, 156-162).

Evaluating the Recovery Curve for Clinically Assessed Reaction Time After Concussion

CONTEXT

  A change in reaction time is one of various clinical measures of neurocognitive function that can be monitored after concussion and has been reported to be among the most sensitive indicators of cognitive impairment.

OBJECTIVE

  To determine the timeline for clinically assessed simple reaction time to return to baseline after a concussion in high school athletes.

DESIGN

  Observational study.

SETTING

  Athletic training room.

PATIENTS OR OTHER PARTICIPANTS

  Twenty-one high school-aged volunteers.

INTERVENTION(S)

  Participants completed 8 trials of the ruler-drop test during each session. Along with baseline measures, a total of 6 additional test sessions were completed over the course of 4 weeks after a concussion (days 3, 7, 10, 14, 21, and 28).

MAIN OUTCOME MEASURE(S)

  The mean reaction times calculated for all participants from each of the 7 test sessions were analyzed to assess the change in reaction time over the 7 time intervals.

RESULTS

  After a concussion and compared with baseline, simple reaction time was, on average, 26 milliseconds slower at 48 to 72 hours postinjury (P < .001), almost 18 milliseconds slower on day 7 (P < .001), and about 9 milliseconds slower on day 10 (P < .001). Simple reaction time did not return to baseline levels until day 14 postinjury.

CONCLUSIONS

  Clinically assessed simple reaction time appeared to return to baseline levels within a timeframe that mirrors other measures of cognitive performance (approximately 14 days).

A review of the validity of computerized neurocognitive assessment tools in mild traumatic brain injury assessment

Computerized neurocognitive assessment tools (NCATs) offer potential advantages over traditional neuropsychological tests in postconcussion assessments. However, their psychometric properties and clinical utility are still questionable. The body of research regarding the validity and clinical utility of NCATs suggests some support for aspects of validity (e.g., convergent validity) and some ability to distinguish between concussed individuals and controls, though there are still questions regarding the validity of these tests and their clinical utility, especially outside of the acute injury timeframe. In this paper, we provide a comprehensive summary of the existing validity literature for four commonly used and studied NCATs (automated neuropsychological assessment metrics, CNS vital signs, cogstate and immediate post-concussion and cognitive testing) and lay the groundwork for future investigations.

Convergent and criterion validity of the CogState computerized brief battery cognitive assessment in women with and without breast cancer

OBJECTIVE

Computerized tests have increasingly garnered interest for assessing cognitive functioning due to their potential logistical and financial advantages over traditional 'pencil and-paper' neuropsychological tests. However, psychometric information is necessary to guide decisions about their clinical and research utility with varied populations. We explored the convergent construct validity and criterion validity of the CogState computerized tests in breast cancer survivors, a group known to present with mostly mild, subtle cognitive dysfunction.

METHOD

Fifty-three post-menopausal women (26 breast cancer survivors, 27 healthy controls) completed the CogState Brief Battery tests with passed performance checks, conceptually matched traditional neuropsychological tests, and a self-report measure of daily functioning, the Functional Activities Questionnaire.

RESULTS

Significant positive correlations were found between the CogState Brief Battery tests and traditional neuropsychological tests, although the traditional tests specifically hypothesized to correlate with CogState tests did not reach statistical significance. Analysis of Covariance results showed preliminary support for criterion validity, as the patient and control groups differed on the traditional test of working memory (Digits Backwards, p = .01), with a trend towards significance for the CogState test of working memory (One Back, p = .02), controlled for age, race, and mood.

CONCLUSIONS

The results provide preliminary support for further research to determine if the CogState tests are viable as screening tools to detect subtle cognitive differences between breast cancer survivors and healthy women. Our study was limited by the low base rate of cognitive impairment and small sample size. We recommend further research employing sufficiently powered sample sizes and a longitudinal, repeated measures study design.

Computerized and fingertip measures of reaction time compared in individuals

The main purpose of our study was to discover the correlation between the field fingertip and computerized methods of measuring reaction time selectively of the dominant and non-dominant hands for individual, non-trained, healthy young people of senior school age. Forty one, 17 year old, strongly right handed scholars, 21 boys and 20 girls with body mass indices between 18.5 and 25.0, participated in the experiment. The field fingertip method employed a metal metric ruler and the computerized method used the Vienna Test System. The point biserial coefficient of correlation between these two methods was calculated for each individual. The results of demonstrated that the vast majority of participants, 95.2% of males and 85.0% of females for the right hand and 95.2% of males and 95.0% of females for the left hand had a high level of point biserial coefficient of correlation between the two methods. A small number of participants, 3 females and 1 male, did not demonstrate a high level of correlation. We speculate that this fact may be due to differential expression of muscle fibre types between males and females. The portability and ease of use of the field fingertip method are advantageous in the field research and provide a reliable measure of reaction time. It is important to control the initial gap between the thumb and index finger of the person being tested. A metallic metric ruler is adequate experimental instrumentation. The mass of the dropped item does not influence the measurement.

The Effects of Repeated Testing, Simulated Malingering, and Traumatic Brain Injury on High-Precision Measures of Simple Visual Reaction Time

Simple reaction time (SRT), the latency to respond to a stimulus, has been widely used as a basic measure of processing speed. In the current experiments, we examined clinically-relevant properties of a new SRT test that presents visual stimuli to the left or right hemifield at varying stimulus onset asynchronies (SOAs). Experiment 1 examined test-retest reliability in 48 participants who underwent three test sessions at weekly intervals. In the first test, log-transformed (log-SRT) z-scores, corrected for the influence of age and computer-use, were well predicted by regression functions derived from a normative population of 189 control participants. Test-retest reliability of log-SRT z-scores was measured with an intraclass correlation coefficient (ICC = 0.83) and equaled or exceeded those of other SRT tests and other widely used tests of processing speed that are administered manually. No significant learning effects were observed across test sessions. Experiment 2 investigated the same participants when instructed to malinger during a fourth testing session: 94% showed abnormal log-SRT z-scores, with 83% producing log-SRT z-scores exceeding a cutoff of 3.0, a degree of abnormality never seen in full-effort conditions. Thus, a log-SRT z-score cutoff of 3.0 had a sensitivity (83%) and specificity (100%) that equaled or exceeded that of existing symptom validity tests. We argue that even expert malingerers, fully informed of the malingering-detection metric, would be unable to successfully feign impairments on the SRT test because of the precise control of SRT latencies that would be required. Experiment 3 investigated 26 patients with traumatic brain injury (TBI) tested more than 1 year post-injury. The 22 patients with mild TBI showed insignificantly faster SRTs than controls, but a small group of four patients with severe TBI showed slowed SRTs. Simple visual reaction time is a reliable measure of processing speed that is sensitive to the effects of malingering and TBI.

Word Recall: Cognitive Performance Within Internet Surveys

BACKGROUND

The use of online surveys for data collection has increased exponentially, yet it is often unclear whether interview-based cognitive assessments (such as face-to-face or telephonic word recall tasks) can be adapted for use in application-based research settings.

OBJECTIVE

The objective of the current study was to compare and characterize the results of online word recall tasks to those of the Health and Retirement Study (HRS) and determine the feasibility and reliability of incorporating word recall tasks into application-based cognitive assessments.

METHODS

The results of the online immediate and delayed word recall assessment, included within the Women's Health and Valuation (WHV) study, were compared to the results of the immediate and delayed recall tasks of Waves 5-11 (2000-2012) of the HRS.

RESULTS

Performance on the WHV immediate and delayed tasks demonstrated strong concordance with performance on the HRS tasks (ρc=.79, 95% CI 0.67-0.91), despite significant differences between study populations (P<.001) and study design. Sociodemographic characteristics and self-reported memory demonstrated similar relationships with performance on both the HRS and WHV tasks.

CONCLUSIONS

The key finding of this study is that the HRS word recall tasks performed similarly when used as an online cognitive assessment in the WHV. Online administration of cognitive tests, which has the potential to significantly reduce participant and administrative burden, should be considered in future research studies and health assessments.

Examining postconcussion symptoms of dizziness and imbalance on neurocognitive performance in collegiate football players

OBJECTIVE

This study examined the effects of symptom reports of dizziness and imbalance on cognitive function in concussed collegiate football players.

DESIGN

Retrospective, descriptive.

SETTING

University athletic medicine facility.

SUBJECTS

Twenty-seven collegiate football players were included in the final analysis: 16 with symptoms of dizziness/imbalance resulting from concussion and 11 without dizziness/imbalance resulting from concussion.

MAIN OUTCOME MEASURES

Participants completed the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) at baseline, at 1 to 2 days postconcussion and 5 to 7 days postconcussion. The ImPACT neurocognitive assessment consists of 6 modules, yielding 4 composite scores: verbal memory, visual memory, visual-motor processing speed, and reaction time. In addition, it includes a postconcussion symptom scale total score.

RESULTS

Results revealed that participants with reports of dizziness and imbalance had significantly lower scores on the ImPACT composite scores; however, these individuals also had an overall higher symptom inventory. When accounting for the additional postconcussion symptoms, time was the only significant effect.

CONCLUSION

Dizziness and imbalance are common symptoms postconcussion; however, these symptoms did not predict performance on acute ImPACT scores. Further research is needed to understand the mechanisms causing postconcussion symptoms, including symptoms of dizziness and imbalance, and influence on outcomes postconcussion.

The impact of making-weight on cognitive performance in apprentice jockeys

Jockeys regularly engage in rapid weight-loss practices in preparation for competition. These practices are thought to impair cognitive function, although the evidence in support of this theory remains inconclusive. The purpose of this study was to examine the effects of making-weight on cognitive function in apprentice jockeys in a simulated and competitive environment. Apprentice jockeys (n = 12) reduced their body mass by 4% in 48 h in a simulated environment using weight-loss methods typically adopted in preparation for racing. Simple and choice reaction time, attention, learning and memory were assessed before and after the weight loss. A further 10 apprentice jockeys performed the cognitive function assessment in a competitive racing environment at both a self-reported "normal" and "light" body mass. Hydration status and body mass were assessed in all trials. In the simulated environment, body mass was reduced by 4.2 ± 0.3%, yet no change in cognitive function was observed. Cognitive function also remained unchanged in the competitive environment after a body mass loss of 5.7 ± 1.9%. Typical reductions in body mass in preparation for racing have no effect on cognitive function in apprentice jockeys in a simulated and competitive environment. Further research is required to investigate the physiological mechanisms preventing the adverse effects of making-weight on cognitive function in jockeys.

Minimal cognitive impairment in UK HIV-positive men who have sex with men: effect of case definitions and comparison with the general population and HIV-negative men

Supplemental Digital Content is Available in the Text.

Background:

To determine the prevalence of neurocognitive impairment (NCI) in UK HIV-positive and HIV-negative men who have sex with men (MSM).

Methods:

HIV-positive and HIV-negative participants were recruited to a cross-sectional study from 2 London clinics and completed computer-assisted neuropsychological tests and questionnaires of depression, anxiety, and activities of daily living. Published definitions of HIV-associated neurocognitive disorders (HAND) and global deficit scores were used. Age- and education-adjusted neuropsychological test scores were directly compared with reference population data.

Results:

A total of 248 HIV-positive and 45 HIV-negative MSM participated. In the HIV-positive group, median time since diagnosis was 9.4 years, median CD4⁺ count was 550 cells per cubic millimeter, and 88% were on antiretroviral therapy. Prevalence of HAND was 21.0% in HIV-positive MSM (13.7% asymptomatic neurocognitive impairment, 6.5% mild neurocognitive disorder, and 0.8% HIV-associated dementia). Using a global deficit score threshold of 0.5, the prevalence of NCI was 31.5% (when averaged over 5 neuropsychological domains) and 40.3% (over 10 neuropsychological test scores). These results were not significantly different from the HIV-negative study sample. No consistent pattern of impairment was seen in HIV-positive patients relative to general male population data (n = 380).

Conclusions:

We found a prevalence of HAND and degree of impairment on neuropsychological testing of HIV-positive MSM that could represent a normal population distribution. These findings suggest that NCI may be overestimated in HIV-positive MSM, and that the attribution of NCI to HIV infection implied by the term HAND requires revision.

Prospective clinical assessment using Sideline Concussion Assessment Tool-2 testing in the evaluation of sport-related concussion in college athletes

OBJECTIVE

To evaluate the utility of the Sideline Concussion Assessment Tool (SCAT)-2 in collegiate athletes with sport-related concussion.

DESIGN

Prospective cross-sectional study with baseline testing and serial repeat testing after concussion in contact sport athletes and non-concussed control athletes.

SETTING

Division I University.

PARTICIPANTS

Male and female club rugby and varsity athletes.

INTERVENTIONS

Baseline measures of concussion symptoms, cognitive function, and balance were obtained using the SCAT-2. Serial postinjury testing was conducted as clinically indicated.

MAIN OUTCOME MEASURES

The SCAT-2 total and subset scores were calculated and evaluated at baseline and after injury.

RESULTS

The total SCAT-2 score and the composite scores of symptoms, symptom severity, and balance were significantly different in concussed groups after injury when compared with baseline. When comparing performance in concussed versus control athletes, all subcomponents of the SCAT-2 were significantly different. No differences in baseline SCAT-2 scores were seen based on self-reported history of concussion. At baseline, anxiety and depression screening scores were associated with higher symptom scores. When compared with baseline, a 3.5-point drop in SCAT-2 score had 96% sensitivity and 81% specificity in detecting concussion. When examined to exclude baseline scores, a cutoff value of 74.5 was associated with 83% sensitivity and 91% specificity in predicting concussion versus control status.

CONCLUSIONS

The SCAT-2 total composite score and each subcomponent are useful in the assessment of concussion. As SCAT-3 is similar to SCAT-2, it is expected that it too will be a useful tool.

Validity of a screening tool for detecting subtle cognitive impairment in the middle-aged and elderly

The present study tested 121 middle-aged and elderly community-dwelling individuals on the computer-based Subtle Cognitive Impairment Test (SCIT) and compared their performance with that on several neuropsychological tests. The SCIT had excellent internal consistency, as demonstrated by a high split-half reliability measure (0.88-0.93). Performance on the SCIT was unaffected by the confounding factors of sex, education level, and mood state. Many participants demonstrated impaired performance on one or more of the neuropsychological tests (Controlled Oral Word Association Task, Rey Auditory and Verbal Learning Task, Grooved Pegboard [GP], Complex Figures). Performance on SCIT subtests correlated significantly with performance on many of the neuropsychological subtests, and the best and worst performing quartiles on the SCIT subtest discriminated between good and poor performers on other subtests, collectively indicating concurrent validity of the SCIT. Principal components analysis indicated that SCIT performance does not cluster with performance on most of the other cognitive tests, and instead is associated with decision-making efficacy, and processing speed and efficiency. Thus, the SCIT is responsive to the processes that underpin multiple cognitive domains, rather than being specific for a single domain. Since the SCIT is quick and easy to administer, and is well tolerated by the elderly, it may have utility as a screening tool for detecting cognitive impairment in middle-aged and elderly populations.

Return to rugby after brain concussion: a prospective study in 35 high level rugby players

Background:

Although guidelines based on expert opinions have been developed for the immediate management and return to play of athletes after a concussion, data are lacking on this issue.

Objectives:

Evaluate a standardized management of brain concussion among rugby players to prevent the recurrence.

Patients and Methods:

A prospective study was performed from September 2009 to June 2012. All rugby players who had a concussion when playing rugby were included. Patients were managed by a specialized hospital team with a specific protocol developed in collaboration with the medical staff of the rugby clubs included in the study. The series included 35 rugby players, with 23 professionals and 12 high-level players, 30 men and 5 women, mean age 23.1 ± 5.5 years old. The median number of previous concussions was 2 (0-30) episodes. According to the Cantu concussion severity classification, 3 athletes were grade 1, 12 were grade 2 and 20 were grade 3. None of the injured athletes was lost to follow-up. The primary endpoint was the occurrence of a new concussion within 3 months after the first in patients who returned to rugby.

Results:

Thirty-three patients returned to rugby after a mean 22.1 ± 10 days. The recurrence rate within 3 months was 2/33 (6.1%). The median delay before returning to rugby was 21 (7-45) days. Factors associated with a delayed return to play were young age, initial loss of consciousness, severity Cantu grade 3 and post-concussive syndrome of more than 5 days. Analysis of two failures showed that the initial injury was grade 3 and that both were professional athletes and had a history of concussion.

Conclusions:

This prospective study validated the study protocol for the management of concussion in rugby players.

Effect of acute exercise on clinically measured reaction time in collegiate athletes

PURPOSE

We have developed a reliable and valid clinical test of reaction time (RTclin) that is sensitive to the acute effects of concussion. If RTclin is to be used as a sideline concussion assessment tool then the acute effects of exercise on RTclin may need to be controlled for. The purpose of this study was therefore to determine the effect of exercise on RTclin.

METHODS

A gender-balanced group of 42 collegiate athletes were assigned to an exercise (n = 28) and a control (n = 14) group using 2:1 block randomization. The exercise group completed a graded four-stage exercise protocol on a stationary bicycle (100 W × 5 min; 150 W × 5 min; 200 W × 5 min; sprint × 2 min), whereas the control group was tested at identical periods without exercising. Mean RTclin was calculated for eight trials as the fall time of a vertically suspended rigid shaft after its release by the examiner before being caught by the athlete. RTclin was measured at baseline and after each of the four stages.

RESULTS

As both HR and RPE significantly increased for the four stages in the exercise group (P < 0.001), mean RTclin showed a significant overall decline during repeated test administration (P < 0.008). However, there were no significant group (exercise vs control, P = 0.822) or group-by-stage interaction (P = 0.169) effects on RTclin as assessed by repeated-measures analysis of variance.

CONCLUSIONS

Exercise did not appear to affect RTclin performance in this study. This suggests that RTclin measured during a sideline concussion assessment does not need to be adjusted to account for the acute effects of exercise.

Advanced topics in neuropsychological assessment following sport-related concussion

OBJECTIVE

This study examined seven topics relating to neuropsychological assessment following sport-related concussion: (i) traditional vs. computerized tests; (ii) the value of baseline, pre-season testing; (iii) invalid baseline scores and poor effort; (iv) when to assess following injury; (v) the reliability of neuropsychological tests; (vi) reliable change methodology; and (vii) new methods for identifying cognitive impairment.

MAIN RESULTS

Baseline testing can be helpful for quantifying cognitive deficits following injury and for assessing recovery. At present, however, there is insufficient evidence to conclude that having baseline test results is clearly superior to not having baseline test results. Although invalid baseline test performance can be detected in some athletes, validity indicators cannot determine the extent to which the results were due to deliberately poor performance, confusion or misunderstanding regarding some aspect of the test, distractions in group testing environments or some combination of factors. When interpreting baseline and post-injury data, sophisticated psychometric methods (e.g. reliable change, multivariate base rates) are available to assist with more accurate identification of cognitive impairment and the serial monitoring of recovery.

CONCLUSIONS

The value of neuropsychological assessment in the management of sport-related concussion has a strong empirical foundation. Additional research is needed, however, to refine its use.

Systematic review of appropriate cognitive assessment instruments used in clinical trials of schizophrenia, major depressive disorder and bipolar disorder

Cognitive dysfunction is increasingly recognized as a symptom in mental conditions including schizophrenia, major depressive disorder (MDD), and bipolar disorder (BPD). Despite the many available cognitive assessment instruments, consensus is lacking on their appropriate use in clinical trials. We conducted a systematic literature review in Embase, PubMed/Medline and PsychINFO to identify appropriate cognitive function instruments for use in clinical trials of schizophrenia, MDD, and BPD. Instruments were identified from the articles. Instruments and articles were excluded if they did not address schizophrenia, MDD, or BPD. Instrument appropriateness was further assessed by the criteria of the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) initiative: test-retest reliability, utility, relationship to functional status, potential changeability to pharmacological agents, and tolerability and practicality for clinical trials. The database search yielded 173 articles describing 150 instruments used to assess cognitive function. Seventeen additional instruments were identified through Google and clinicaltrials.gov. Among all these, only 30 (18%) were deemed appropriate for use in the diseases of interest. Of these, 27 were studied in schizophrenia, one in MDD and two in BPD. These findings suggest the need for careful selection of appropriate cognitive assessment instruments, as not all may be valid in these disorders.

Athletes' age, sex, and years of education moderate the acute neuropsychological impact of sports-related concussion: a meta-analysis

The objective of this study is to determine which pre-existing athlete characteristics, if any, are associated with greater deficits in functioning following sports-related concussion, after controlling for factors previously shown to moderate this effect (e.g., time since injury). Ninety-one independent samples of concussion were included in a fixed+systematic effects meta-analysis (n = 3,801 concussed athletes; 5,631 controls). Moderating variables were assessed using analogue-to-ANOVA and meta-regression analyses. Post-injury assessments first conducted 1-10 days following sports-related concussion revealed significant neuropsychological dysfunction, postural instability and post-concussion symptom reporting (d = -0.54, -1.10, and -1.14, respectively). During this interval, females (d = -0.87), adolescent athletes competing in high school competitions (d = -0.60), and those with 10 years of education (d = -1.32) demonstrated larger post-concussion neuropsychological deficits than males (d = -0.42), adults (d = -0.25), athletes competing at other levels of competition (d = -0.43 to -0.41), or those with 16 years of education (d = -0.15), respectively. However, these sub-groups' differential impairment/recovery beyond 10 days could not be reliably quantified from available literature. Pre-existing athlete characteristics, particularly age, sex and education, were demonstrated to be significant modifiers of neuropsychological outcomes within 10 days of a sports-related concussion. Implications for return-to-play decision-making and future research directions are discussed.

Executive functions and intraindividual variability following concussion

The long-term outcomes of executive functions and intraindividual variability (IIV; i.e., trial-to-trial or across-task variability in cognitive performance) following concussion are unclear due to inconsistent and limited research findings, respectively.

OBJECTIVE

Responding to these gaps in scientific understanding, the current study aimed to assess the utility of both executive functions and IIV at predicting concussion history.

METHOD

Altogether 138 self-identified athletes (Mage = 19.9 ± 1.91 years, 60.8% female, 19.6% with one concussion, 18.1% with two or more concussions) completed three executive-related cognitive tasks (i.e., n-back, go/no-go, global-local). Ordinal logistic regression analyses examined the joint effect of person-mean and IIV as predictors of concussion status.

RESULTS

Only mean response time for the global-local task predicted the number of past concussions, while no IIV variables reached unique significance.

CONCLUSIONS

IIV research on concussion remains limited; however, the preliminary results do not indicate any additional value of IIV indices above mean performances at predicting past concussion. For executive functions, shifting appears most sensitive at detecting concussion group differences, with past researchers identifying post concussion impairment in attentional processing.

Between-seasons test-retest reliability of clinically measured reaction time in National Collegiate Athletic Association Division I athletes

CONTEXT

Reaction time is typically impaired after concussion. A clinical test of reaction time (RT(clin)) that does not require a computer to administer may be a valuable tool to assist in concussion diagnosis and management.

OBJECTIVE

To determine the test-retest reliability of RTclinmeasured over successive seasons in competitive collegiate athletes and to compare these results with a computerized measure of reaction time (RT(comp)).

DESIGN

Case series with repeated measures.

SETTING

Preparticipation physical examinations for the football, women's soccer, and wrestling teams at a single university.

PATIENTS OR OTHER PARTICIPANTS

102 National Collegiate Athletic Association Division I athletes.

INTERVENTION(S)

The RT(clin) was measured using a measuring stick embedded in a weighted rubber disk that was released and caught as quickly as possible. The RT(comp) was measured using the simple reaction time component of CogState Sport.

MAIN OUTCOME MEASURE(S)

Data were collected at 2 time points, 1 season apart, during preparticipation physical examinations. Outcomes were mean simple RT(clin) and RT(comp).

RESULTS

The intraclass correlation coefficient estimates from season 1 to season 2 were 0.645 for RT(clin) (n = 102, entire sample) and 0.512 for RT(comp) (n = 62 athletes who had 2 consecutive valid baseline CogState Sport test sessions).

CONCLUSIONS

The test-retest reliability of RT(clin) over consecutive seasons compared favorably with that of a concurrently tested computerized measure of reaction time and with literature-based estimates of computerized reaction time measures. This finding supports the potential use of RT(clin) as part of a multifaceted concussion assessment battery. Further prospective study is warranted.

Normative Data in a Sample of Canadian University Athletes Using ANAM Tests

The baseline / postconcussion neuropsychological (NP) assessment model has been shown to be of clinical value and currently contributes significant information in sport concussion evaluation. Computerized NP batteries are now widely used in elite sport environments and are rapidly becoming more commonly utilized at the community level. With the growth of computerized NP testing, it is important to identify and understand unique characteristics with respect to baseline NP performance. The Automated Neuropsychological Assessment Metrics (ANAM) is a library of computerized NP tests designed to detect speed and accuracy of attention, memory, and thinking ability. This article describes baseline ANAM test scores in a sample of Canadian university athletes and explores the following two factors: (a) performance differences between male and female student-athletes using ANAM tests and (b) the relationship between self-reported history of concussion and baseline NP performance.

Cerebral Concussion in Sport: An Overview

Sports-related concussions are ubiquitous in contact and collision sports at all levels of play and across a broad age range. Once thought to be a nuisance injury, it is now recognized that these brain injuries may lead to chronic neurocognitive impairment if not managed properly. This paper provides a broad overview of the research and clinical data that have emerged in this rapidly growing area. Included in the review are discussions of injury definition, pathophysiology, signs and symptoms, epidemiology, potential long-term consequences, assessment, and psychological factors. Issues of prevention and education are discussed in light of further increasing awareness of this injury.