Cognitive remediation in residential substance use treatment: A randomized stepped-wedge trial.

ABSTRACTExecutive dysfunction is common in individuals with substance use disorder (SUD) and presents a barrier to treatment engagement. The study aimed to investigate the effectiveness of cognitive remediation (CR) for improving executive functioning and treatment retention in patients with SUD, using a stepped-wedge cluster randomized controlled trial. The sample included 527 adults enrolled across ten residential SUD treatment providers in NSW, Australia. The intervention consisted of 12 hours of CR delivered over six weeks in a group format. The comparator was treatment-as-usual (TAU). Primary outcomes included self-reported executive functioning and proportion of treatment completed (PoTC), measured as the number of days in treatment divided by the planned treatment duration. Intention-to-treat analysis did not find significant differences for self-reported executive functioning (mean difference = -2.49, 95%CI [-5.07, 0.09], p = .059) or PoTC (adjusted mean ratio = 1.09, 95%CI [0.88, 1.36], p = .442). Due to high dropout from the intention-to-treat sample (56%) a post-hoc analysis was conducted using a per-protocol approach, in which CR was associated with improved self-reported executive functioning (mean difference = -3.33, 95%CI [-6.10, -0.57], p = .019) and improved likelihood of treatment graduation (adjusted odds ratio = 2.43, 95%CI [1.43, 4.11], p < .001). More research is required to develop a CR approach that results in service-wide treatment effectiveness.

Neuropsychological Deficits in Disordered Screen Use Behaviours: A Systematic Review and Meta-analysis.

Over the last few decades, excessive and disordered screen use has become more prevalent, prompting investigations into its associated consequences. The extent to which disordered screen use behaviours impact neuropsychological functioning has been reportedly mixed and at times inconsistent. This review sought to synthesise the literature and estimate the magnitude of overall cognitive impairment across a wide range of disordered screen use behaviours. We also sought to determine the cognitive domains most impacted, and whether the observed impairments were moderated by the classification of screen-related behaviours (i.e., Internet or gaming) or the format of cognitive test administration (i.e., paper-and-pencil or computerised). A systematic search of databases (Embase, PsycINFO, MEDLINE) identified 43 cross-sectional articles that assessed neuropsychological performance in disordered screen use populations, 34 of which were included in the meta-analysis. A random-effects meta-analysis revealed significant small/medium (g = .38) cognitive deficits for individuals with disordered screen use behaviours relative to controls. The most affected cognitive domain with a significant medium effect size (g = .50) was attention and focus followed by a significant reduction in executive functioning (g = .31). The classification of disordered screen use behaviours into Internet or gaming categories or the format of cognitive testing did not moderate these deficits. Additionally, excluding disordered social media use in an exploratory analysis had little effect on the observed outcomes. This study highlights a number of methodological considerations that may have contributed to disparate findings and shows that disordered screen use can significantly impact cognitive performance. Recommendations for future research are also discussed. Data for this study can be found at https://osf.io/upeha/ .

Cognitive Remediation as an Adjunct Treatment for Substance Use Disorders: A Systematic Review.

Substance use disorders are associated with diverse neuropsychological impairments, with deficits in memory and executive functioning commonly observed. Cognitive remediation has been shown to be effective in other populations with cognitive impairments in these domains, including those with psychiatric disorders and acquired brain injuries, and it has been hypothesised to be similarly effective for those in treatment for substance use disorders. We aimed to systematically review the evidence for cognitive remediation interventions administered as an adjunct treatment to substance use rehabilitation. Studies were included if participants were receiving substance use treatment, if improving cognitive functioning was the main focus of the intervention and if they used an experimental design with a control condition receiving treatment-as-usual or an active control intervention. Two independent reviewers agreed on the final selection of 32 studies, encompassing cognitive remediation for working memory, memory, executive functioning and general cognition. Significant differences between intervention and control groups for cognitive test results and treatment outcomes were extracted and compared across treatment approaches. The review found considerable heterogeneity across studies, including in the types of interventions, the nature of participants and the outcome measures used. Further, a lack of quality studies with sufficient power meant that limited conclusions could be drawn, highlighting a need for further replication and research. However, findings indicate that cognitive remediation remains a promising potential avenue for improving cognition and treatment outcomes for those in treatment for substance use disorders. Protocol submitted prospectively to PROSPERO 30.09.2019, CRD42020150978.

Rates of false positive outcomes on the A-WPTAS picture items in a sample of non-concussed athletes.

Accurate diagnosis of sports related concussion ensures that athletes are removed from play if concussed and prevents incorrect removal when a concussion has not occurred. Although various screening tools are currently in use, there is no gold standard measure with which to diagnose sports related concussion.Objective: The current study aimed to investigate the diagnostic accuracy of the Abbreviated Westmead Post Traumatic Amnesia Scale (A-WPTAS) picture task, a neurocognitive measure used to assess mild traumatic brain injury. The incidence of false positive classifications and the potential confounding effect of exercise on scores on the A-WPTAS picture items were examined.Methods: The study included an athlete group comprising 33 players and a control group comprising 37 subjects. The A-WPTAS picture task was completed on three testing occasions, separated by three week intervals.Results: Results revealed that the A-WPTAS picture task was highly accurate (>95%) in correctly classifying participants with no concussion across all three testing occasions. There was no significant difference between the two groups in relation to false positive outcomes on any testing occasion, suggesting that exercise was not a confounding factor.Conclusions: Findings provide preliminary evidence to support the use of the A-WPTAS picture task in a sporting context.

Length of post-traumatic amnesia and its prediction of neuropsychological outcome following severe to extremely severe traumatic brain injury in a litigating sample.

Primary Objective: The aim of the current study was to examine the relationship between duration of post-traumatic amnesia (PTA) and neuropsychological outcome at one or more years following severe to extremely severe traumatic brain injury (TBI) in a litigating sample. Research Design: Retrospective study design, using data collected from 2010 to 2017. Methods and Procedures: Data from 41 cases obtained from a private medicolegal neuropsychological database was examined. The database comprised information pertaining to TBI etiology, TBI severity parameters, demographic variables, neuropsychological test results and scores on psychological questionnaires. PTA duration was examined as a continuous variable. All cases that demonstrated non-credible effort were excluded. Main Outcomes and Results: Continuous PTA duration was not found to be a significant predictor of cognitive impairment across domains of verbal intellect, non-verbal intellect, working memory, information processing speed, immediate memory, delayed memory, and executive functioning. Conclusions: The predictive relationship between duration of PTA and cognitive impairment that has been reported in non-litigating populations did not exist in a litigating TBI sample. Findings illustrate the importance of investigating the relationships between injury variables and cognitive outcome in a population undergoing litigation, to provide better understanding of outcome in this subgroup of patients with TBI.

Perceived cognitive difficulties and cognitive test performance as predictors of employment outcomes in people with multiple sclerosis.

Perceived cognitive difficulties and cognitive impairment are important determinants of employment in people with multiple sclerosis (pwMS). However, it is not clear how they are related to adverse work outcomes and whether the relationship is influenced by depressive symptoms. Thus, this study examined perceived and actual general cognitive and prospective memory function, and cognitive appraisal accuracy, in relation to adverse work outcomes. The possible mediating and/or moderating role of depression was also examined. A cross-sectional community-based sample of 111 participants (33 males, 78 females) completed the Multiple Sclerosis Work Difficulties Questionnaire (MSWDQ), Beck Depression Inventory - Fast Screen (BDI-FS), and questions related to their current or past employment. They then underwent cognitive testing using the Screening Examination for Cognitive Impairment, Auditory Consonant Trigrams test, Zoo Map Test, and Cambridge Prospective Memory Test. Perceived general cognitive and prospective memory difficulties in the workplace and performance on the respective cognitive tests were found to predict unemployment and reduced work hours since MS diagnosis due to MS. Depression was also related to reduced work hours, but it did not explain the relationship between perceived cognitive difficulties and the work outcomes. Nor was it related to cognitive test performance. The results highlight a need to address the perceptions of cognitive difficulties together with cognitive impairment and levels of depression in vocational rehabilitation programs in pwMS.

A neuropsychological comparison of siblings with neurological versus hepatic symptoms of Wilson's Disease.

Wilson's Disease (WD) (also known as hepatolenticular degeneration) is a rare inherited autosomal recessive disorder of abnormal copper metabolism, with an estimated prevalence of approximately 1 in 30,000. The clinical features associated with WD are highly varied. However, subtypes generally reflect neurological, hepatic, and psychiatric symptoms. The present case study reports two brothers with a recent diagnosis of WD. Neurological symptoms and cognitive deficits were exhibited in one brother (BL) in the form of extrapyramidal features, while the other brother (AL) only exhibited hepatic symptoms. Extensive neuropsychological testing was conducted on both siblings to compare cognitive profiles. Results for BL indicated significantly impaired motor functioning and information processing speed, which impacted him significantly at school. Aspects of executive dysfunction were also apparent in addition to reduced visual and verbal memory, working memory, and attention. Results for AL revealed evidence of verbal memory difficulties and aspects of executive dysfunction. Comparison is made of the distinct and common cognitive characteristics of the cases presented in terms of implications for early intervention and management of cognitive difficulties.

Identifying posttraumatic amnesia in individuals with a Glasgow Coma Scale of 15 after mild traumatic brain injury.

OBJECTIVE: To examine the utility of the Abbreviated Westmead Post-traumatic Amnesia Scale, which includes the Glasgow Coma Scale (GCS) and 3 picture cards used to measure amnesia, in identifying the presence or absence of posttraumatic amnesia in individuals with mild traumatic brain injury (mTBI). DESIGN: Prospective study using data from the Abbreviated Westmead Post-traumatic Amnesia Scale. SETTING: Trauma hospital. PARTICIPANTS: Individuals with possible mTBI who presented between April and September 2011 (N=252; age range, 18-65y; mean age, 37.4±13.9y; 77% men). INTERVENTION: Administration of the Abbreviated Westmead Post-traumatic Amnesia Scale. MAIN OUTCOME MEASURES: GCS and Abbreviated Westmead Post-traumatic Amnesia Scale pass/fail rates. RESULTS: Of the individuals, 169 (mean age, 35.1±13.6y; 77% men) received the scale. A pass/fail performance was achieved a median 121 minutes (interquartile range, 89-205min) after triage. Of the 45 who failed, 31 (69%) had a GCS score of 15. The likelihood of failing was associated with being older (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.02-1.06; P<.05), having consumed alcohol (OR, 3.09; 95% CI, 1.42-6.74; P<.01), and the scale being administered closer to the time of the injury (OR, 0.99; 95% CI, 0.99-1.00; P<.05). Nineteen (42%) of those who failed had consumed alcohol, 11 had a GCS score of 15, and 8 had a GCS score of 14. CONCLUSIONS: A GCS score of 15 does not always signify return to normative cognitive function. Individuals with a GCS score of 15 who are acutely cognitively impaired are at risk of not being accurately identified. The addition of an amnesia score to the GCS in the Abbreviated Westmead Post-traumatic Amnesia Scale will assist in making a diagnosis of mTBI.

Prevalence and predictors of poor sleep quality in mild cognitive impairment.

AIMS: To investigate the prevalence of and contributors to poor sleep quality in patients with mild cognitive impairment (MCI). METHODS: Data were collected for 158 patients meeting the criteria for MCI. Measures included the Pittsburgh Sleep Quality Index, Geriatric Depression Scale, and Mini-Mental State Examination. Demographic, lifestyle, medication, and substance use data were also collected. RESULTS: A total of 63% of patients with MCI demonstrated sleep disturbance, a significantly higher rate than that of the controls (44%; chi-square = 8.77; P = .003). Depressive symptoms, cognition, antidepressant usage, alcohol consumption, age, and education were identified as significant predictors of self-reported sleep quality in patients with MCI (R(2) = .327, F 6,145 = 11.729, P < .0001). CONCLUSIONS: Sleep disturbance occurs in around two-thirds of patients with MCI. Interventions addressing depression, cognition, and substance and medication use may improve sleep quality in MCI.

Effects of concomitant spinal cord injury and brain injury on medical and functional outcomes and community participation.

BACKGROUND: There are limited data on the interactions between concomitant spinal cord injury (SCI) and traumatic brain injury (TBI) in terms of medical, psychological, functional, and community outcomes. OBJECTIVE: To investigate the hypothesis that in addition to SCI-associated sensory-motor impairments, people with dual diagnosis would experience additional TBI-associated cognitive impairments that would have a negative impact on community reintegration. METHODS: Cross-sectional, case-matched study comparing a consecutive sample of participants with dual diagnosis (n = 30) to an SCI group (n = 30) and TBI group (n = 30). Participants who were on average 3.6 years postrehabilitation discharge were interviewed using a battery of standardized outcome measures. RESULTS: Length of rehabilitation stay was significantly longer in SCI and dual diagnosis participants. Fatigue, pain, sexual dysfunction, depression, and sleep disturbances were frequently reported by all groups. Similar levels of anxiety and depression were reported by participants in all groups, however TBI participants reported higher stress levels. All groups achieved mean FIM scores > 100. The dual diagnosis and SCI groups received more daily care and support than TBI participants. Similar levels of community reintegration were achieved by all groups with a high level of productive engagement in work, study, or volunteer activities. CONCLUSIONS: The findings of this study do not support the hypotheses. Postrehabilitation functioning was better than anticipated in adults with dual diagnosis. The contribution of rehabilitation factors, such as longer admission time to develop compensatory techniques and strategies for adaptation in the community, may have contributed to these positive findings.

Everyday Executive Functioning Profiles in Adults with Down Syndrome.

Research on everyday executive functions in individuals with Down Syndrome (DS) has focused mostly on children and adolescents. The current study examined everyday executive functions in DS adults. 27 DS adults (aged 22.00 to 42.00 years) were tested using the Behaviour Rating Inventory of Executive Function-Adult Informant Version (BRIEF-A). Findings revealed that DS adults exhibited greater impairments in Global Executive Composite (GEC), Working Memory, Plan/Organise, Task-Monitor and the Metacognition Index (MI) relative to typically developing adults in the normative sample. Substantial variabilities were found in all everyday executive function abilities among DS adults. Findings highlight the importance of making comprehensive assessments of everyday executive functions in DS individuals in order to identify problem areas and plan individualised support programmes.

Validity of cognitive screens for HIV-associated neurocognitive disorder: a systematic review and an informed screen selection guide.

Various screening tools have been proposed to identify HIV-Associated Neurocognitive Disorder (HAND). However, there has been no systematic review of their strengths and weaknesses in detecting HAND when compared to gold standard neuropsychological testing. Thirty-five studies assessing HAND screens that were conducted in the era of combination antiretroviral therapy were retrieved using standard search procedures. Of those, 19 (54 %) compared their screen to standard neuropsychological testing. Studies were characterised by a wide variation in criterion validity primarily due to non-standard definition of neurocognitive impairment, and to the demographic and clinical heterogeneity of samples. Assessment of construct validity was lacking, and longitudinal useability was not established. To address these limitations, the current review proposed a summary of the most sensitive and specific studies (>70 %), as well as providing explicit caution regarding their weaknesses, and recommendations for their use in HIV primary care settings.

Not all mentally stimulating activities are alike: insights from a 4-factor model and implications for late-life cognition.

It is not yet known which specific qualities of cognitively stimulating activities are most likely to enhance cognitive reserve in older adults. Taking an inductive approach to this problem, we asked 504 older adults with subjective and/or cognitive impairment to complete the Cognitively Stimulating Activities Questionnaire (CSA-Q). Exploratory factor analysis identified a 4-factor structure within a split-half sample, after which confirmatory factor analysis cross-validated the model. Retaining 12 CSA-Q items, the 4 factors were dubbed CSA-Processing, CSA-Challenging, CSA-Connecting and CSA-Socializing. Resulting factor weights were analyzed relative to cognitive reserve proxies and neuropsychological domains. All factors except CSA-Challenging were positively linked to cognitive reserve. Neuropsychologically, CSA-Challenging was modestly and positively correlated with processing speed and executive function, while CSA-Processing was positively correlated with executive function. CSA-Socializing had a small positive correlation with processing speed. Our findings offer new insights into late-life stimulating activities, laying the groundwork for longitudinal and intervention studies.

Psychometric Properties of a New Decision-Making Capacity Assessment Tool for People with Substance Use Disorder: The CAT-CAT.

Individuals with substance use disorder (SUD) often present with cognitive impairments, which may impede their ability to make decisions for themselves, including treatment-related decisions. It is therefore important to assess whether individuals with SUD have adequate decision-making capacity. Indeed, there have not been any capacity assessment tools tailored for use with SUD populations that demonstrate adequate psychometric properties or that have the strong ethical foundation that is required of capacity assessment tools. The Compulsory Assessment and Treatment-Capacity Assessment Tool (CAT-CAT) was designed to fill this gap in the literature. Therefore, the aim of this study was to establish the interrater and test-retest reliability, and discriminative validity of the CAT-CAT. The first of this two-part study recruited healthcare professionals in New Zealand and asked them to conduct a capacity assessment on two hypothetical clients. Generally, excellent interrater reliability (ρ = .998 overall) and test-retest reliability (ρ = .996 overall) was found. The CAT-CAT has exhibited reliability that was at least comparable to widely used capacity assessment tools for other pathologies. The second part of this study involved cognitively normal individuals undergoing capacity assessments to investigate the hypothesis that individuals that do not lack capacity will obtain scores significantly higher than 50% in each section of the CAT-CAT. This hypothesis was met with highly significant results. To conclude, preliminary data suggest that the CAT-CAT has excellent reliability and correctly classifies those with capacity.

The Alcohol and Drug Cognitive Enhancement (ACE) Screening Tool: A simple and brief questionnaire to screen for cognitive impairment in substance use disorder treatment services.

The objective of this study was to determine the test-retest reliability; construct and criterion validity; and test operating characteristics of a newly developed cognitive impairment risk factor screening instrument, the Alcohol and Drug Cognitive Enhancement (ACE) Screening Tool. Participants in the validation study were 129 adults with substance use disorder (SUD) enrolled in residential SUD treatment services and 209 normal controls. Test and retest data were available for 36 participants with SUD and 40 normal control individuals on the ACE Screening Tool. Test-retest reliability was excellent (ICC = 0.97). The ACE Screening Tool was significantly correlated with the Montreal Cognitive Assessment (MoCA), Behavior Rating Inventory of Executive Functioning-Adult Version (BRIEF-A), Test of Premorbid Functioning (TOPF) and Five Point Test, establishing construct validity. Criterion validity was established using a ternary severity variable constructed using results obtained on the MoCA and BRIEF-A. Test operating characteristics analysis showed 93% sensitivity, 46% specificity, 33% positive predictive power, and 96% negative predictive power using a cut-score of >3. Those high levels of sensitivity and negative predictive power indicated that the tool would likely detect cognitive impairment when present and should therefore be considered suitable as an initial screening tool for cognitive impairment in individuals attending SUD services.

Fifteen minutes of high intensity running can impair performance on concussion testing; Implications for on-field diagnosis in sport.

OBJECTIVES: To examine the effects of 15 min of high intensity treadmill running on concussion testing assessed by the King-Devick test. DESIGN: Prospective Cohort Study. METHODS: Participants self-selected to either a running or a control group. At baseline both groups were assessed using the King-Devick concussion test. The running group then completed 15-minutes of treadmill running at rating of perceived exertion of 7-9/10 while the control group sat quietly. Both groups repeated the King-Devick test following that 15-minute period. RESULTS: Participants (n = 84 men, 53 women) were divided in two groups; running or control. Both groups, on average, had significant improvement after 15 min (suggesting a learning effect). Comparisons between the baseline and re-assessment scores indicated impaired performance was more common following high intensity treadmill running (n = 23 participants, 34.3%) compared to the control group (n = 10 participants, 14.3%, p = 0.006, OR = 3.44 [95%CI 1.40-8.50]). Four participants in the running group worsened their score at reassessment by more than 3 s compared to no participants in the control group. CONCLUSIONS: After 15 min of high intensity treadmill running, 1 in 3 participants scored a slower time at follow-up or committed a mistake compared to baseline. Implications for clinical practise include: the recommendation that baseline tests be conducted at rest and after high intensity exercise to provide accurate comparisons to assist in clinical decision making; and a cut-off of >3 s may be a clinically useful difference between resting baseline and re-assessment using the King-Devick test.

Engagement in cognitively stimulating activities in individuals with Mild Cognitive Impairment: relationships with neuropsychological domains and hippocampal volume.

Late-life participation in cognitively stimulating activities is thought to contribute to an individual's cognitive reserve and thus protect against cognitive decline, yet its association with clinical markers of neurodegeneration is not well established. To investigate, we developed a 13-item self-report "cognitively stimulating activities" questionnaire (CSA-Q), which was completed by a community sample of 269 older adults (>50 years) at risk of dementia. Participants met criteria for Mild Cognitive Impairment (MCI) and were classified as amnestic (aMCI; n = 93) or non-amnestic (naMCI; n = 176). Weighted CSA-Q dimensions were calculated for activity intensity, mental engagement and social engagement via a panel of 23 inter-raters. The CSA-Q mean and its dimensions were examined in relation to: (a) demographics (age, sex), (b) cognitive reserve proxies (years of education, premorbid IQ), (c) neuropsychological markers across cognitive domains of executive function, processing speed, learning, and memory storage, and (d) neuroimaging markers (left and right hippocampal volume). Analyses were conducted for all MCI, as well as for aMCI and naMCI sub-types. The CSA-Q was found to have concurrent validity with cognitive reserve proxies. Among all MCI, the CSA-Q dimensions of intensity and mental engagement had moderate associations with left hippocampal volume, but not with neuropsychological performance. For naMCI, the CSA-Q had moderate associations with left hippocampal volume, and small associations with aspects of executive functioning and processing speed. No equivalent associations emerged for the aMCI subtype. Our findings show that the CSA-Q may be particularly useful for older adults with non-amnestic cognitive deficits.

Validation of the Abbreviated Westmead Post-traumatic Amnesia Scale: a brief measure to identify acute cognitive impairment in mild traumatic brain injury.

OBJECTIVE: To validate the use of the Abbreviated Westmead Post-traumatic Amnesia Scale (A-WPTAS) in the assessment of acute cognitive impairment in mild traumatic brain injury (mTBI). METHODS: Data previously collected from 82 mTBI and 88 control participants using the Revised Westmead Post-traumatic Amnesia Scale (R-WPTAS) was converted to A-WPTAS scores and pass/fail classifications were calculated for both scales. RESULTS: The proportion of failures on the R-WPTAS and the A-WPTAS did not differ and a similar number of mTBIs were classified on each. For mTBIs the relationship between the independent memory test and a pass/fail classification was the same for both scales. Bivariate logistic regressions revealed that mTBIs, relative to controls, were around 8 times more likely to fail the assessment (R-WPTAS: 95% CI: 3.70-18.87; A-WPTAS: 95% CI: 3.70-20.14). As verbal learning improved the likelihood of failure was reduced. Greater education was associated with a decreased likelihood of failure. The relationship between education and a fail performance was not sustained when education was adjusted for the effect of age, prior mTBI, blood alcohol level, injury status, verbal learning, and morphine administration. CONCLUSIONS: The A-WPTAS is a valid measure. The A-WPTAS may reduce the risk of failing to classify patients with mTBI by identifying and documenting acute cognitive impairment.

Chronic Neurophysiological Effects of Repeated Head Trauma in Retired Australian Male Sport Athletes.

Aim: This study investigated the somatosensory and corticomotor physiology of retired contact sport athletes with a history of repeated concussion/subconcussion head trauma. Methods: Retired male athletes with a history of playing contact sports and repeated head trauma (n = 122) were divided into two groups: those who expressed concerns regarding their mental and cognitive health ("symptomatic": n = 83), and those who did not express any ongoing concerns ("asymptomatic": n = 39). Both groups were compared to age-matched male controls (n = 50) with no history of concussions or participation in contact sports, an absence of self-reported cognitive, or mood impairments. Transcranial magnetic stimulation (TMS) and vibrotactile stimulation were used to assess corticomotor and somatosensory pathways respectively. TMS and vibrotactile stimulation were correlated to self-reported responses using the Fatigue and Related Symptom Survey. Linear regression was used to associate concussion history with TMS, somatosensory variables. Results: Significant differences were found in symptom survey scores between all groups (p < 0.001). TMS showed significant differences between the "symptomatic" and control groups for intracortical inhibition and paired pulse TMS measures. Somatosensory measures showed significant differences for reaction time (p < 0.01) and reaction time variability (p < 0.01) between the "symptomatic" group to the "asymptomatic" and control groups. For other somatosensory measures, the "symptomatic" measures showed differences to the "control" group. Correlations showed significant associations between severity of symptom reporting with TMS and somatosensory measure, and regression revealed the number of concussions reported was shown to have significant relationships to increased intracortical inhibition and poorer somatosensory performance. Conclusion: This study shows that retired contact sport athletes expressing chronic symptoms showed significant pathophysiology compared to those with no ongoing concerns and non-concussed controls. Further, there is a linear dose-response relationship between number of reported concussions and abnormal neurophysiology. Neurophysiological assessments such as TMS and somatosensory measures represent useful and objective biomarkers to assess cortical impairments and progression of neuropsychological impairment in individuals with a history of repeated head trauma.

Diffusion Tensor Imaging in Sport-Related Concussion: A Systematic Review Using an a priori Quality Rating System.

Diffusion tensor imaging (DTI) of brain white matter (WM) may be useful for characterizing the nature and degree of brain injury after sport-related concussion (SRC) and assist in establishing objective diagnostic and prognostic biomarkers. This study aimed to conduct a systematic review using an a priori quality rating strategy to determine the most consistent DTI-WM changes post-SRC. Articles published in English (until June 2020) were retrieved by standard research engine and gray literature searches (N = 4932), using PRISMA guidelines. Eligible studies were non-interventional naturalistic original studies that conducted DTI within 6 months of SRC in current athletes from all levels of play, types of sports, and sex. A total of 29 articles were included in the review, and after quality appraisal by two raters, data from 10 studies were extracted after being identified as high quality. High-quality studies showed widespread moderate-to-large WM differences when SRC samples were compared to controls during the acute to early chronic stage (days to weeks) post-SRC, including both increased and decreased fractional anisotropy and axial diffusivity and decreased mean diffusivity and radial diffusivity. WM differences remained stable in the chronic stage (2-6 months post-SRC). DTI metrics were commonly associated with SRC symptom severity, although standardized SRC diagnostics would improve future research. This indicates that microstructural recovery is often incomplete at return to play and may lag behind clinically assessed recovery measures. Future work should explore interindividual trajectories to improve understanding of the heterogeneous and dynamic WM patterns post-SRC.