Evolving concepts of chronic traumatic encephalopathy as a neuropathological entity

Chronic traumatic encephalopathy (CTE) is a long‐term neurodegenerative consequence of repetitive head impacts which can only be definitively diagnosed in post‐mortem. Recently, the consensus neuropathological criteria for the diagnosis of CTE was published requiring the presence of the accumulation of abnormal tau in neurons and astroglia distributed around small blood vessels at the depths of cortical sulci in an irregular pattern as the mandatory features. The clinical diagnosis and antemortem prediction of CTE pathology remain challenging if not impossible due to the common co‐existing underlying neurodegenerative pathologies and the lack of specific clinical pointers and reliable biomarkers. This review summarizes the historical evolution of CTE as a neuropathological entity and highlights the latest advances and future directions of research studies on the topic of CTE.     

Dual-task gait differences in female and male adolescents following sport-related concussion

Concussion may affect females and males differentially. Identification of gender-related differences after concussion, therefore, may help clinicians with individualized evaluations. We examined potential differences in dual-task gait between females and males after concussion. Thirty-five participants diagnosed with a concussion (49% female, mean age = 15.0 ± 2.1 years, 7.5 ± 3.0 days post-injury) and 51 controls (51% female, mean age = 14.4 ± 2.1 years) completed a symptom inventory and single/dual-task gait assessment. The primary outcome variable, the dual-task cost, was calculated as the percent change between single-task and dual-task conditions to account for individual differences in spatio-temporal gait variables. No significant differences in symptom severity measured by the post-concussion symptom scale were observed between females (32.0 ± 18.0) and males (27.8 ± 18.2). Compared with males, adolescent females walked with significantly decreased cadence dual-task costs after concussion (−19.7% ± 10.0% vs. −11.3% ± 9.2%, p = 0.007) when adjusted for age, height, and prior concussion history. No significant differences were found between female and male control groups on other dual-task cost gait measures. Females and males with concussion also walked with significantly shorter stride lengths than controls during single-task (females: 1.13 ± 0.11 m vs. 1.26 ± 0.11 m, p = 0.001; males: 1.14 ± 0.14 m vs. 1.22 ± 0.15 m, p = 0.04) and dual-task gait (females: 0.99 ± 0.10 m vs. 1.10 ± 0.11 m, p = 0.001; males: 1.00 ± 0.13 m vs. 1.08 ± 0.14 m, p = 0.04). Females demonstrated a significantly greater amount of cadence change between single-task and dual-task gait than males after a sport-related concussion. Thus, differential alterations may exist during gait among those with a concussion; gender may be one prominent factor affecting dual-task gait.     

An analysis of injuries resulting from professional horse racing in France during 1991-2001: a comparison with injuries resulting from professional horse racing in Great Britain during 1992-2001

Background

It has been previously shown that professional jockeys suffer high rates of fatal and non‐fatal injuries in the pursuit of their occupation. Little is known, however, about differences in injury rates between countries.

Aim

To determine the rate of fatal and non‐fatal injuries in flat and jump jockeys in France and to compare the injury rates with those in Great Britain and Ireland

Method

Prospectively collected injury data on professional jockeys were used as the basis of the analysis.

Results

Limb fractures occur four times more often in both flat and jump racing in France than in Great Britain. Similarly dislocations are diagnosed 20 times more often in flat and three times more often in jump racing. This difference is surprising given that French jockeys have fewer falls per ride than their British counterparts in flat racing, although they do have more falls than the British in jump racing. Similarly concussion rates seem to be higher in French jockeys, although there may be a difference in the diagnostic methods used in the different countries. By contrast, soft tissue injuries account for a far smaller percentage of injuries than in Great Britain.

Conclusion

There are striking differences in injury rates between countries which may be explained in part by a difference in track conditions—for example, harder tracks in France—or different styles of racing—for example, larger fields of horses per race in France.     

Concussion history is not a predictor of computerised neurocognitive performance

Background

The long term effects of self reported concussion on neurocognitive functioning have been found to be variable.

Objectives

To evaluate cognitive performance on the Headminder concussion resolution index (CRI) and ImPACT assessment tests of subjects with and without a history of self reported concussion.

Methods

A retrospective analysis was completed on 235 Headminder CRI baseline assessments and 264 ImPACT baseline assessments. Participants were divided into four groups on the basis of reported number of concussions (zero, one, two, or three). Multivariate analysis of variance was used to evaluate differences between the concussion history groups on the two computer based concussion assessment programs.

Results

Multivariate analysis of variance indicated no significant difference between those with and without a history of concussion on the CRI (Λ  =  0.963, F_{(15, 627.05)}  =  0.57, p  =  0.898). It also revealed no significant differences between groups on the ImPACT test (Λ  =  0.951, F_{(12, 672.31)}  =  1.07, p  =  0.381).

Conclusions

The results suggest that either long term cognitive decrements may not be associated with a history of concussion or the decrements may be subtle and undetectable by these computer programs.     

Concussive head injury in children and adolescents related to sports and other leisure physical activities

Objective

To compare the characteristics of children and adolescents with concussive head injury (CHI) sustained during organised sports or other leisure physical activity.

Methods

This was a case series study reviewing the medical records retrospectively over a four year period of children 6–16 years presenting to the emergency department with a CHI after participating in sport and/or recreation activity.

Results

There were 592 cases of sport and recreation related concussion over the study period (2000–2003). Most of the patients (n  =  424, 71.6%) were male, with half (n  =  304, 51.4%) being older than 10 years of age. A total of 152 (25.7%) cases of CHI were related to playing sports. Most cases (71.2%) were mild concussion. The cause of injury was a fall (n  =  322, 54.4%) or a collision. Nearly a quarter of the children (n  =  143, 24.2%) were admitted to hospital, with imaging performed in 134 (22.7%). Most children were treated appropriately and no adverse events were reported.

Conclusions

A severe CHI in a child is six times more likely to have resulted from organised sport than from other leisure physical activities. Outcomes for CHI in children is excellent, although their management places a considerable burden on emergency services. The need for activity restriction and the benefits of this in reducing long term cognitive effects of CHI are uncertain.     

American Academy of Pediatrics

In brief How—and if—exercise alters immunity is open to debate. Research centers on changes in the number and function of granulocytes and lymphocytes and in levels of immunoglobulins. In general, these immune changes are mixed, mild, and brief. Clinical studies are inconclusive and fraught with confounders, especially the impact of psychological stress. Whether exercise enhances immunity or impairs it may, in fact, depend on whether the exercise is a joy or a stress.     

Exercise-Associated Collapse

Exercise-associated collapse (EAC) is the most common reason that athletes are treated in the medical tent following an endurance event. The pathophysiology of EAC is postural hypotension that results when the loss of muscle pumping action caused by the cessation of exercise is combined with cutaneous vasodilation. EAC usually occurs after an athlete crosses the finish line. If an athlete collapses during a race, then another serious medical cause is more likely. A brief assessment of the collapsed athlete should be carried out to obtain a working diagnosis. Prompt treatment of EAC includes elevating the legs and pelvis of the athlete.     

Tracking Your Heart Rate for Fitness

Objectives. Baseline and post-concussive neurocognitive testing is useful in managing concussed athletes. The Concussion in Sport Group has postulated that the use of psychotropic medications is a modifying factor in the management of sport-related concussion. About 7% of US adolescents are prescribed psychotropics in a given year. Our aim was to investigate whether psychotropic medication use or psychiatric illness is associated with differences in baseline neurocognitive test scores. Methods. From 2007 to 2012, over 7000 athletes underwent pre-participation baseline neurocognitive testing using the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery. Following application of inclusion and exclusion criteria, athletes’ self-reported medication lists were reviewed and: 1) classified as psychotropic or not and 2) subclassified. Group subclassification yielded: 1) use of any psychotropic medication, 2) psychostimulant use, 3) antidepressant use and 4) self-reported history of depression and/or anxiety without psychotropic use. Each group was matched, by sex, age, body mass index, education level and concussion history with athletes who were not reportedly prescribed psychotropic medications or did not report a depression/anxiety history, respectively. Each group’s baseline ImPACT scores were compared to matched controls. Results. The use of prescribed psychotropic medications without regard to subclass had no effect on baseline ImPACT composite scores among athletes ages 13–25. However, athletes reportedly prescribed psychostimulants displayed significantly lower visual motor speed scores (32.8 vs 37.1, p = 0.030) and slower reaction times (0.65 vs 0.60, p = 0.044) than non-users. In contrast, antidepressant users displayed significantly faster reaction times (0.58 vs 0.61, p = 0.029). Those reporting a history of depression/anxiety, not treated with psychotropics, displayed significantly lower visual memory (70.4 vs 75.2, p = 0.010) and higher symptom scores (8.83 vs 4.72, p = 0.005). Conclusions. This pilot study suggests that self-reported psychotropic medications are associated with differences in baseline ImPACT test scores, which appear dependent on medication subclass. Our preliminary results support the inclusion of psychotropic medications, specifically psychostimulants and antidepressants, as well as history of depression/anxiety as potential concussion modifiers.     

Physical activity following acute concussion and persistent postconcussive symptoms in children and adolescents

The management of concussion in pediatric patients has always been guided by treatment guidelines that have been drawn from consensus statements rather than clinical research projects. Grool and colleagues conducted a clinical research project on an early return to physical activity and its effect on post-concussion symptoms. The study enrolled 3063 pediatric patients, age 5.0 to 17.99 years of age who presented to one of nine Pediatric Emergency Research Centers in Canada. 2413 patients completed the primary outcome for exposure. A total of 1677 patients (69.5%) instituted some level of early physical activity, including light aerobic exercise (n = 795 or 32.9%), sport-specific exercise (n = 214 or 8.9%), non-contact drills (n = 143 or 5.9%), full-contact practice (n = 106 or 4.4%), or full competition (n = 419 or 17.4%), while 736 (30.5%) instituted no physical activity. Patients were evaluated by a web-based survey or a telephone-based survey at days 7 and 28 after their initial visit, and their symptoms were evaluated by using the Post Concussive Symptom Inventory (PCSI). Early return to physical activity was associated with a lower risk of Persistent Post-Concussive Syndrome (PPCS) than in patients reporting no physical activity at 28 days (24.6% vs. 43.5%, Absolute risk difference, (ARD), 18.9% (95% CI 14.7–23.0%). Among the sub-group of patients who were symptomatic at day 28 (n = 803), PPCS was more present in the patients that reported no physical activity, (n = 584: PPCS 52.9%), than those with light aerobic activity (n = 494 [46.4%; ARD, 6.5%; 95% CI 5.7–12.5%], moderate activity [n = 176 (38.6%; ARD, 14.3%; 95% CI 5.9%-22.2%], or full contact activity [n = 133 (36.1%; ARD, 16.8%; 95% CI 7.5%- 25.5%]. Therefore, in patients aged 5 to 18 years with acute concussion, a return to physical activity within 7 days of acute injury was associated with less symptoms at 28 days than in patients who had a period of prolonged rest rather than an early return to physical activity.     

Mild Traumatic Brain Injury: A Place for Social Work

Mild traumatic brain injury (mTBI) has emerged as a significant public health issue. Increases in both the prevalence and awareness of this injury have resulted in a greater demand for mTBI-informed care. Our exploratory, qualitative study examines the work lives of front-line mTBI professionals. Findings suggest that mTBI rehabilitation work often requires substantial emotional energy given the impact that injury-related issues have on professionals’ therapeutic work with clients. We suggest that social work, with a focus on the psychosocial implications of injury and recovery, is well-positioned to take a larger role in mTBI care and rehabilitation.