Stress as a diagnostic challenge for postconcussive symptoms: sequelae of mild traumatic brain injury or physiological stress response

Cognition and post-concussive symptom status after pediatric mild traumatic brain injury

Cognitive impairment and post-concussive symptoms (PCS) represent hallmark sequelae of pediatric mild traumatic brain injury (pmTBI). Few studies have directly compared cognition as a function of PCS status longitudinally. Cognitive outcomes were therefore compared for asymptomatic pmTBI, symptomatic pmTBI, and healthy controls (HC) during sub-acute (SA; 1-11 days) and early chronic (EC; approximately 4 months) post-injury phases. We predicted worse cognitive performance for both pmTBI groups relative to HC at the SA visit. At the EC visit, we predicted continued impairment from the symptomatic group, but no difference between asymptomatic pmTBI and HCs. A battery of clinical (semi-structured interviews and self-report questionnaires) and neuropsychological measures were administered to 203 pmTBI and 139 HC participants, with greater than 80% retention at the EC visit. A standardized change method classified pmTBI into binary categories of asymptomatic or symptomatic based on PCS scores. Symptomatic pmTBI performed significantly worse than HCs on processing speed, attention, and verbal memory at SA visit, whereas lower performance was only present for verbal memory for asymptomatic pmTBI. Lower performance in verbal memory persisted for both pmTBI groups at the EC visit. Surprisingly, a minority (16%) of pmTBI switched from asymptomatic to symptomatic status at the EC visit. Current findings suggest that PCS and cognition are more closely coupled during the first week of injury but become decoupled several months post-injury. Evidence of lower performance in verbal memory for both asymptomatic and symptomatic pmTBI suggests that cognitive recovery may be a process separate from the resolution of subjective symptomology.

The Buffalo Concussion Treadmill and Bike Tests in People With Mild-to-Moderate Traumatic Brain Injury: An Exploratory Clinical Audit

OBJECTIVE

To assess the performance on the Buffalo Concussion Treadmill and Bike Tests in nonathletic people following a mild-to-moderate traumatic brain injury.

SETTING

An outpatient rehabilitation clinic.

PARTICIPANTS

Forty-nine patients with mild-to-moderate traumatic brain injury who underwent the Buffalo Concussion Treadmill or Bike Test as usual clinical care.

DESIGN

A retrospective clinical audit.

MAIN MEASURES

Demographics and brain injury-specific clinical data, Depression Anxiety Stress Scale; Rivermead Post-Concussion Symptom Questionnaire, and performance outcomes on the Buffalo Concussion Treadmill or Bike Test.

RESULTS

Forty-nine patients (mean age: 33.7 ± 13.0 years), on average 56.2 ± 36.4 days post-injury, completed the Buffalo Concussion Treadmill or Bike Test. Fourteen patients stopped the test due to symptom exacerbation with a mean test duration of 8.1 ± 4.5 minutes, reaching an age-predicted maximum heart rate of 72.9% ± 12.4% and reporting a rating of perceived exertion of 13.4 ± 2.2. Those who terminated the test for other reasons had a significantly longer test duration (14.0 ± 4.7 minutes, P = .01), with a higher age-predicted maximum heart rate (83.3% ± 12.8%, P = .01) and rating of perceived exertion (17.0 ± 2.5, P = .01). Within the group who stopped for other reasons, 10 were due to symptoms deemed unrelated to the injury at the time of the test and 2 were stopped by the therapist for safety reasons. A significant but weak correlation between heart rate and rating of perceived exertion existed only for those who terminated the test for other reasons ( r = 0.38, P = .02). Overall, a shorter test duration was associated with higher scores of both self-reported depression ( r = -0.41, P < .01) and late postconcussion symptoms ( r = -0.40, P < .01).

CONCLUSION

The Buffalo Concussion Treadmill or Bike Test can be used in the nonathletic mild-to-moderate traumatic brain injury population to differentiate between those who experience symptom exacerbation during exercise and those who do not based on symptom exacerbation, test duration, and poor perception of exertion. Further research is required to determine whether other reasons for test termination are related to the injury.

Impairments in Physiological Reactivity to Emotive Stimuli After Traumatic Brain Injury: A Systematic Review of Skin Conductance and Heart Rate Variability Evidence

OBJECTIVE

To examine evidence of impairments in physiological reactivity to emotive stimuli following traumatic brain injury (TBI).

METHODS

A search of PsychINFO, CINAHL (Cumulative Index to Allied Health Literature), Web of Science, EMBASE (Excerpta Medica dataBASE), and Scopus databases was conducted from 1991 to June 24, 2021, for studies comparing changes in skin conductance or heart rate variability to emotive stimuli between adults with TBI and controls. Two reviewers independently assessed eligibility and rated methodological quality.

RESULTS

Twelve eligible studies examined physiological reactivity to laboratory-based emotive stimuli, which included nonpersonal pictures/videos, posed emotion, stressful events, and personal event recall. Overall, 9 reported evidence that individuals with TBI experience lower physiological reactivity to emotive stimuli compared with healthy controls, although the findings varied according to the type and valence of emotional stimuli and physiological parameter. Most studies using nonpersonal pictures or videos found evidence of lower physiological reactivity in TBI participants compared with controls.

CONCLUSIONS

Based on laboratory-based studies, individuals with TBI may experience lower physiological reactivity to emotive stimuli. Further research is needed to investigate physiological responses to personally relevant emotional stimuli in real-world settings and to understand the interplay between physiological reactivity, subjective experiences, and behavior.

Attachment and Clinical Outcomes Among Treatment-Seeking Adults With Persistent Symptoms After Mild Traumatic Brain Injury

OBJECTIVE

Interpersonal attachment influences the development and course of disease. Overreliance on insecure attachment strategies may increase risk for poor disease outcomes. This study aimed to investigate largely unexplored relationships between attachment strategies and clinical outcomes among adults with persistent symptoms after mild traumatic brain injury (mTBI).

METHODS

Participants with persistent symptoms after mTBI (N=83) completed measures assessing dimensions of insecure attachment (Relationship Scales Questionnaire [RSQ]), persistent symptoms (Rivermead Post-Concussion Symptoms Questionnaire), depression (Patient Health Questionnaire-9), anxiety (Generalized Anxiety Disorder-7), and health-related quality of life (HRQOL) (Quality of Life After Brain Injury-Overall Scale). Questionnaires were administered at clinic intake (mean=18.1 weeks postinjury) and again 3-4 months later (mean=32.2 weeks postinjury), except the RSQ, which was administered only in the follow-up assessment. Treatment response for each outcome was calculated as the difference between scores at clinic intake and follow-up. Generalized linear models were fitted for each clinical outcome, with RSQ variables as predictors.

RESULTS

Higher attachment anxiety was associated with greater persistent symptom severity, greater depression and anxiety symptoms, and worse HRQOL at follow-up. Higher attachment anxiety was also associated with less improvement in depression and HRQOL over time. In contrast, attachment avoidance was unrelated to any of the clinical outcomes.

CONCLUSIONS

Attachment anxiety, the fear that a significant other will not be available in stressful circumstances, may be a particularly important social factor associated with health among adults with persistent symptoms after mTBI. Greater consideration of the attachment system is warranted in mTBI care and research.

The role of the stress system in recovery after traumatic brain injury: A tribute to Bruce S. McEwen

Traumatic brain injury (TBI) represents a major public health concern. Although the majority of individuals that suffer mild-moderate TBI recover relatively quickly, a substantial subset of individuals experiences prolonged and debilitating symptoms. An exacerbated response to physiological and psychological stressors after TBI may mediate poor functional recovery. Individuals with TBI can suffer from poor stress tolerance, impairments in the ability to evaluate stressors, and poor initiation (and cessation) of neuroendocrine stress responses, all of which can exacerbate TBI-mediated dysfunction. Here, we pay tribute to the pioneering neuroendocrinologist Dr. Bruce McEwen by discussing the ways in which his work on stress physiology and allostatic loading impacts the TBI patient population both before and after their injuries. Specifically, we will discuss the modulatory role of hypothalamic-pituitary-adrenal axis responses immediately after TBI and later in recovery. We will also consider the impact of stressors and stress responses in promoting post-concussive syndrome and post-traumatic stress disorders, two common sequelae of TBI. Finally, we will explore the role of early life stressors, prior to brain injuries, as modulators of injury outcomes.

Association between perceived distress and salivary cortisol in veterans with mTBI

Mild traumatic brain injury (mTBI) is one of the most common injuries experienced by Veterans and can frequently result in a variety of post-concussive symptoms. Post-concussive headaches (PCH), one of the most common symptoms, can persist for years after the injury occurred. The long-lasting impacts of PCH can be extremely distressing for Veterans, thus necessitating the need to find reliable biomarkers that directly relate to subjective feelings of distress. Yoga-based interventions have been shown to improve both subjective and objective markers of stress. Techniques used in yoga, such as the focus on releasing muscular tension, are also recommended as strategies for treating PCH. Thus, yoga-based interventions provide a unique context for the comparison of subjective and objective measures of distress in Veterans with PCH. In this secondary, exploratory analysis, we examined the relationship between perceived distress and cortisol in sixteen Veterans with mTBI and long-term PCH within the context of a yoga intervention feasibility study. The Visual Analogue Scale (VAS), a validated tool for measuring subjective distress, was administered to participants immediately before and after 75-min yoga classes, which occurred twice weekly over eight weeks. Participants also provided salivary cortisol (pre- and post-yoga) at in-person sessions (eight) to compare to changes in VAS scores. We found that VAS scores were significantly reduced within five of the eight assessed yoga classes, but there were no significant changes in cortisol levels. No significant correlations were found between VAS scores and salivary cortisol levels. When looking at how cortisol levels changed over time (i.e., over the series of eight yoga sessions), there was a significant downward trajectory in post-yoga cortisol, but not after taking pre-class cortisol into account (i.e., within yoga session cortisol change over time). Taken together, we found that subjective distress, but not cortisol was reduced by yoga classes. These data suggest that salivary cortisol did not match changes in perceived distress, thus emphasizing the ongoing challenges of relating subjective and objective measures.

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Perceived distress can negatively impact post-concussive symptoms.

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Efforts are needed to relate objective and subjective measures of distress.

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Subjective distress and salivary cortisol were examined within yoga sessions.

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Subjective distress, but not cortisol was reduced within 5 of 8 yoga classes.

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These data highlight the challenges of relating subjective and objective measures.

History of Functional Somatic Syndromes and Persistent Symptoms After Mild Traumatic Brain Injury

OBJECTIVE

Somatization is thought to underlie functional somatic syndromes (FSSs) and may also contribute to prolonged symptoms after mild traumatic brain injury (mTBI). The investigators evaluated the prevalence of FSSs in patients seeking specialty care after mTBI and whether a history of FSSs was associated with symptom persistence.

METHODS

A total of 142 patients with mTBI completed questionnaires regarding demographic information, injury characteristics, and medical history, including history of diagnosed FSSs at clinic intake (mean=41 days postinjury [SD=22.41]). Postconcussion symptoms were assessed at clinic intake and again 1 and 3 months later. A linear mixed-effects model was used to determine whether history of FSSs was related to persistent mTBI symptoms over time.

RESULTS

A history of at least one FSS was reported by 20.4% of patients. In the linear mixed model, postconcussion symptom scores were not significantly different over time among patients with a history of one or more FSSs or two or more FSSs from those with no FSSs. A history of one or more FSSs or two or more FSSs (versus no FSS) was not associated with increased odds of severe postconcussion symptoms at clinic intake (one or more FSSs: odds ratio=0.88, 95% CI=0.38-2.03; two or more FSSs: odds ratio=1.78, 95% CI=0.45-7.03), at the 1-month follow-up visit (one or more FSSs: odds ratio=0.57, 95% CI=0.22-1.45; two or more FSSs: odds ratio=0.57, 95% CI=0.14-2.37), or at the 3-month follow-up visit (one or more FSSs: odds ratio=0.97, 95% CI=0.36-2.63; two or more FSSs: odds ratio=1.27, 95% CI=0.29-5.65).

CONCLUSIONS

In this sample, the prevalence rates of FSSs were higher than rates previously reported for the general population. However, FSS history did not predict higher postconcussion symptom burden at clinic intake or persistence over the following 3 months. Further research is needed to clarify the potential role of somatization in poor mTBI outcome.

Autonomic dysfunction in adults following mild traumatic brain injury: A systematic review

BACKGROUND

Increasing evidence suggests autonomic nervous system (ANS) dysfunction may occur following mild traumatic brain injury (mTBI). Measures of heart rate, heart rate variability, blood pressure and baroreceptor sensitivity can be used to evaluate ANS dysfunction following mTBI.

OBJECTIVE

Summarize the evidence for ANS dysfunction in adults following mTBI.

METHODS

A search of Embase, MEDLINE, Cochrane Central Register, PsycINFO, CINAHL and SPORTDiscus databases was conducted. Search topics included: mTBI and ANS. Identified abstracts were independently reviewed by 2 reviewers followed by full text screening. Risk of bias was assessed using a modified SIGN checklist. A structured synthesis was performed.

RESULTS

Thirty-nine studies (combined 1,467 participants diagnosed with mTBI) evaluating ANS function were included. ANS function was evaluated under various conditions including: rest, during exertion, cold pressor test, Valsalva maneuver, using face cooling and eyeball pressure paradigms. Short-term or ultra-short-term recordings were most common. The majority of studies (28/39) were rated as "unacceptable" for quality of evidence.

CONCLUSIONS

Altered parameters of ANS function have been reported in multiple conditions following mTBI, both acutely and in the post-acute/chronic stages of recovery. However, due to methodological limitations, conclusions regarding the severity and timing of ANS dysfunction following mTBI cannot be drawn.

Unclear outcomes of heart rate variability following a concussion: a systematic review

PURPOSE

: To systematically regroup articles that were published since the latest systematic search, but with specific inclusion criteria to help comparison that will offer a focused presentation of methods and results. This will offer a full overview of HRV's behavior at rest and during exercise in adults post-concussion.

METHODS

: The systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) method. A computer-based systematic search was conducted in December 2019 through the Pubmed, Scopus and SPORTDiscus databases. A manual search was performed through the reference list of all articles retained. The reliability of the systematic search was assured by having the article selection process entirely repeated by a second author.

RESULTS

: The systematic search yielded a total of 15 articles to be further analyzed. Results show impairment of HRV during exercise for individuals with concussion, heterogenous studies with lack of control over confounding factors and only less than half of the results showing a significant difference between individuals with concussion and controls.

CONCLUSION

: Further research should try standardizing HRV measurement protocols that control confounding factors to allow easier comparison between studies and allows the possibility for an eventual meta-analysis.

Neurorehabilitation of Persistent Sport-Related Post-Concussion Syndrome

BACKGROUND

Persistent Sport-Related Post-Concussion Syndrome is often diagnosed with any type of prolonged PCS symptoms. However, there are not specific diagnostic criteria for PPCS such that misdiagnosis often occurs. Further, the signs and symptoms of PCS overlap with other common illnesses such as depression, anxiety, migraines, ADHD and others. Misdiagnosis may lead to less than efficacious treatment, resulting in prolonged symptoms.

OBJECTIVE

This article will review relevant evidence-based literature on PCS, pointing out the lack of a systemic diagnostic framework. It will also provide evidence that highlights the multiple conflicting findings in the literature. This article will posit the BioPsychoSocial framework as the best diagnostic framework for understanding the impact of concussions on the person and to generate individualized and personal interventions.

METHODS

A narrative review of sport concussion-related articles was conducted, after extensive searches of relevant and non-relevant literature by each author, as well as articles recommended by colleagues. Articles varied from American Academy of Neurology Class I to IV for evaluation and critique. Class IV articles were reviewed, as there is much public misconception regarding sport and other concussion treatment that needed identification and discussion.

RESULTS

Articles reviewed varied by quality of research design and methodology. Multiple symptoms, recovery patterns and rehabilitation treatment approaches are purported in the sport-related concussion literature. Current consensus data as well as the mixed and contradictory findings were explored.

CONCLUSIONS

Persistent Sport-Related Post-Concussion Syndrome is a topic of great interest to both professionals and the general public. There is much misunderstanding about the etiology, causation, diagnostic formulations, symptom presentation, prolonging factors and treatment involved in this syndrome. This article posits an individualized multi-system diagnostic formulation, examining all relevant factors, as generating the best interventions for neurorehabilitation of Persistent Sport-Related Post-Concussion Syndrome.

Placebo Effects in Traumatic Brain Injury

In recent years, several randomized controlled trials evaluating pharmaceutical treatments for traumatic brain injury (TBI) have failed to demonstrate efficacy over placebo, with both active and placebo arms improving at comparable rates. These findings could be viewed in opposing ways, suggesting on the one hand failure of the tested outcome, but on the other, representing evidence of robust placebo effects in TBI. In this article, we examine several of the primary psychological processes driving placebo effects (verbal suggestion, cognitive re-framing, interpersonal interactions, conditioning, therapeutic alliance, anxiety reduction) as well as placebo neurobiology (top-down cortical regulation, reward system activation, dopaminergic and serotonergic neurotransmission). We then extrapolate from the literature to explore whether something inherent in TBI makes it particularly responsive to placebos. Viewed as such here, placebos may indeed represent a powerful and effective treatment for a variety of post-TBI complaints.

Concussion and the autonomic nervous system: An introduction to the field and the results of a systematic review

BACKGROUND

Recent evidence suggests that autonomic nervous dysfunction may be one of many potential factors contributing to persisting post-concussion symptoms.

OBJECTIVE

This is the first systematic review to explore the impact of concussion on multiple aspects of autonomic nervous system functioning.

METHODS

The methods employed are in compliance with the American Academy of Neurology (AAN) and PRISMA standards. Embase, MEDLINE, PsychINFO, and Science Citation Index literature searches were performed using relevant indexing terms for articles published prior to the end of December 2016. Data extraction was performed by two independent groups, including study quality indicators to determine potential risk for bias according to the 4-tiered classification scheme of the AAN.

RESULTS

Thirty-six articles qualified for inclusion in the analysis. Only three studies (one Class II and two Class IV) did not identify anomalies in measures of ANS functioning in concussed populations.

CONCLUSIONS

The evidence supports the conclusion that it is likely that concussion causes autonomic nervous system anomalies. An awareness of this relationship increases our understanding of the physical impact of concussion, partially explains the overlap of concussion symptoms with other medical conditions, presents opportunities for further research, and has the potential to powerfully inform treatment decisions.

Feasibility of using normobaric hypoxic stress in mTBI research

Studies of mild traumatic brain injury (mTBI) recovery generally assess patients in unstressed conditions that permit compensation for impairments through increased effort expenditure. This possibility may explain why a subgroup of individuals report persistent mTBI symptoms yet perform normally on objective assessment. Accordingly, the development and utilization of stress paradigms may be effective for enhancing the sensitivity of mTBI assessment. Previous studies, discussed here, indirectly but plausibly support the use of normobaric hypoxia as a stressor in uncovering latent mTBI symptoms due to the overlapping symptomatology induced by both normobaric hypoxia and mTBI. Limited studies by our group and others further support this plausibility through proof-of-concept demonstrations that hypoxia reversibly induces disproportionately severe impairments of oculomotor, pupillometric, cognitive and autonomic function in mTBI individuals.

Impact of Exercise on Clinical Symptom Report and Neurocognition after Concussion in Children and Adolescents

Recovery from concussion in childhood is poorly understood, despite its importance in decisions regarding return to normal activity. Resolution of post-concussive symptoms (PCS) is widely employed as a marker of recovery in clinical practice; however, it is unclear whether subtle impairments persist only to re-emerge in the context of increased physical or cognitive demands. This study aimed to examine the effect of strenuous exercise on clinical symptom report and neurocognition in children and adolescents after PCS resolution after concussion. We recruited children and adolescents with concussion (n = 30) on presentation to an Emergency Department (ED). At Day 2 and Day 10 post-self-reported symptom resolution, participants completed a strenuous exercise protocol, and pre- and post-exercise assessment of PCS and neurocognition. Results demonstrated an overall reduction in PCS from Day 2 to Day 10 post-symptom resolution, with no evidence of symptom increase after strenuous exercise at either time point. Neurocognitive performance was linked to task complexity: on less cognitively demanding tasks, processing speed was slower post-exercise and, unexpectedly, slower on Day 10 than Day 2, while for more demanding tasks (new learning), Day 2 exercise resulted in faster responses, but Day 10 processing speed post-exercise was slower. In summary, we found the expected recovery pattern for PCS, regardless of exercise, while for neurocognition, recovery was dependent on the degree of cognitive demand, and there was an unexpected reduction in performance from Day 2 to Day 10. Findings provide some suggestion that premature return to normal activities (e.g., school) may slow neurocognitive recovery.

A History of Mild Traumatic Brain Injury Affects Peripheral Pulse Oximetry during Normobaric Hypoxia

Introduction

Physiological and emotional stressors increase symptoms of concussion in recently injured individuals and both forms of stress-induced symptoms in people recovering from mild traumatic brain injury (mTBI), but who are asymptomatic when not stressed or are at rest.

Methods

Healthy asymptomatic adults (25.0 ± 5.1 years) with a history of mTBI (n = 36) and matched healthy controls (HC) (n = 36) with no mTBI history were exposed to three levels of normobaric hypoxic stress generated with the Reduced Oxygen Breathing Device (ROBD) (Environics, Inc., Tollande, CT, USA), which reduced the percent O₂ by mixing sea level air with nitrogen. The ROBD reduced the percent O₂ in the breathable air from the normal 21% to 15.5% O₂, 14% O₂, and 13% O₂. Under these conditions: (a) a standard pulse oximeter recorded peripheral oxygen saturation (SpO₂) and pulse rate (beats per minute) and (b) the Functional Impairment Tester (FIT) (PMI, Inc., Rockville, MD, USA) recorded saccadic velocity and pupillary response dynamics to a brief light flash.

Results

For all three hypoxic stress conditions, the mTBI group had significantly higher SpO₂ during the final minute of exposure than did the controls [F(2.17,151.8) = 5.29, p < 0.001, η² = 0.852] and the rate of SpO₂ change over time was significantly shallower for the mTBI than for the controls [F(2.3,161.3) = 2.863, p < 0.001, η² = 0.569], Greenhouse–Geisser corrected. Overall, mTBI had lower pulse rate but the difference was only significant for the 14% O₂ condition. FIT oculomotor measures were not sensitive to group differences. When exposed to mild or moderate normobaric hypoxic stress (15% O₂): (1) SpO₂ differences emerged between the mTBI and matched HC groups, (2) heart rate trended lower in the mTBI group, and (3) FIT measures were not sensitive to group differences.

Conclusion

A relatively minor hypoxic challenge can reveal measurable differences in SpO₂ and heart rate in otherwise asymptomatic individuals with a history of mTBI.

Subacute posttraumatic complaints and psychological distress in trauma patients with or without mild traumatic brain injury

OBJECTIVE

To identify the frequency, nature and profile of complaints for trauma patients with and without mild traumatic brain injury (mTBI), and to assess their relation to anxiety and depression.

METHODS

A prospective cohort study in a level-one trauma centre was conducted. Mild traumatic brain injury patients and trauma controls were approached for participation. Two weeks after injury, The Head Injury Symptom Checklist (HISC) and the Hospital Anxiety and Depression Scale (HADS) were administered.

RESULTS

Two-hundred seventy two patients with mTBI and 125 TC patients completed the questionnaires. Differences were demonstrated between the two trauma populations on frequency and nature of reported complaints. Ordinal common factor analysis on the mTBI scores yielded three factors: mental distress, physical discomfort, and sensory disbalance, which were all significantly correlated to anxiety and depression scores. Discriminant analyses identified a subset of complaints which could allocate almost 80% of patients to the correct group.

CONCLUSIONS

Patients with mTBI showed a different pattern of complaints than orthopaedic control patients. A mental distress factor consisting of both somatic and cognitive complaints proved to be most discriminating and showed high correlations with anxiety and depression.

Treatment of persistent post-concussion syndrome due to mild traumatic brain injury: current status and future directions

Persistent post-concussion syndrome caused by mild traumatic brain injury has become a major cause of morbidity and poor quality of life. Unlike the acute care of concussion, there is no consensus for treatment of chronic symptoms. Moreover, most of the pharmacologic and non-pharmacologic treatments have failed to demonstrate significant efficacy on both the clinical symptoms as well as the pathophysiologic cascade responsible for the permanent brain injury. This article reviews the pathophysiology of PCS, the diagnostic tools and criteria, the current available treatments including pharmacotherapy and different cognitive rehabilitation programs, and promising new treatment directions. A most promising new direction is the use of hyperbaric oxygen therapy, which targets the basic pathological processes responsible for post-concussion symptoms; it is discussed here in depth.

Complementary and alternative medicine (CAM) following traumatic brain injury (TBI): Opportunities and challenges

Traumatic brain injury (TBI) is highly prevalent and occurs in a variety of populations. Because of the complexity of its sequelae, treatment strategies pose a challenge. Given this complexity, TBI provides a unique target of opportunity for complementary and alternative medicine (CAM) treatments. The present review describes and discusses current opportunitites and challenges associated with CAM research and clinical applications in civilian, veteran and military service populations. In addition to a brief overview of CAM, the translational capacity from basic to clinical research to clinical practice will be described. Finally, a systematic approach to developing an adoptable evidence base, with proof of effectiveness based on the literature will be discussed. Inherent in this discussion will be the methodological and ethical challenges associated with CAM research in those with TBI and associated comorbidities, specifically in terms of how these challenges relate to practice and policy issues, implementation and dissemination. This article is part of a Special Issue entitled SI:Brain injury and recovery.

Predictors of outcome after treatment of mild traumatic brain injury: a pilot study

OBJECTIVE

To determine factors affecting outcome of comprehensive outpatient rehabilitation of individuals who sustained a mild traumatic brain injury.

PARTICIPANTS

From a 4-year series of referrals, 49 nonconsecutive participants met criteria for mild traumatic brain injury (ie, loss of consciousness <30 minutes, Glasgow Coma Scale score >12).

SETTING

Outpatient, community-based postconcussion clinic at a rehabilitation hospital.

MAIN MEASURES

Participants and therapy staff completed the Mayo-Portland Adaptability Inventory-Fourth Edition (MPAI-4) at the initiation and conclusion of treatment. Participants were also administered the Trail Making Test at the start of treatment.

RESULTS

Participants generally gave poorer adaptability ratings than staff at the beginning and discharge of treatment. Regression analyses revealed that after controlling for baseline ratings, psychiatric history was associated with worse participant-rated MPAI-4 Adjustment scores at treatment discharge, whereas better Trail Making Test Part B performance at initiation of treatment predicted better participant-rated MPAI-4 Ability at treatment discharge.

CONCLUSIONS

Premorbid demographic and baseline neurocognitive factors should be taken into account prior to comprehensive treatment of mild traumatic brain injury, as they can influence long-term outcomes. Adaptability ratings from both staff and participants can be useful in gaining different perspectives and assessing factors affecting recovery.

Sustained outcomes following mild traumatic brain injury: results of a five-emergency department longitudinal study

OBJECTIVE

To report on the occurrence of sustained outcomes including post-concussion symptoms, health services used and indicators of social disruption following a mild traumatic brain injury (MTBI).

RESEARCH DESIGN

A dual cohort comparing MTBI Emergency Department (ED) patients and a comparison group of non-head injured ED patients.

METHODS AND PROCEDURES

The outcomes measures employed were the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) and indicators of health services used and social disruption all recorded at the ED and at 3 and 6 months post-ED discharge. 'Sustained' meant a positive response to these measures at 3 and 6 months.

MAIN OUTCOMES AND RESULTS

Reasonable follow-up success was achieved at 3 and 6 months and the cohorts were alike on all demographic descriptors. RPQ average score and symptom occurrence were far more frequent among MTBI patients than for the comparison cohort from 3 to 6 months. The use of health services and indicators of social disruption were also more frequent among MTBI post-discharge patients.

CONCLUSIONS

These findings argue that some with an MTBI suffer real complaints and they are sustained from 3 to at least 6 months. More effort should be given toward specificity of these symptoms from those reported by members of the comparison group.

Neuropsychiatry of persistent symptoms after concussion

A minority of individuals will continue to experience debilitating symptoms for more than several months after sustaining a concussion. These problems may have multiple causes, including persistence of the original concussion symptoms, but they also may be due to factors such as depression and anxiety, physical problems, and psychological issues (including coping with an adverse insurance and legal system). This article reviews the differential diagnosis and treatment strategies for patients with chronic symptoms that persist after a concussion.

Preinjury resilience and mood as predictors of early outcome following mild traumatic brain injury

There is significant heterogeneity in outcomes following mild traumatic brain injury (mTBI). While several host factors (age, gender, and preinjury psychiatric history) have been investigated, the influence of preinjury psychological resilience and mood status in conjunction with mild TBI remains relatively unexplored. Euthymic mood and high resilience are potentially protective against anxiety and postconcussion symptoms, but their relative contributions are currently unknown. This prospective study obtained preinjury estimates of resilience and mood measures in addition to measures of anxiety (Acute Stress Disorder Scale and PTSD-Checklist-Civilian form) and postconcussion symptom severity (Rivermead Post Concussion Symptoms Questionnaire) <24 hours (Baseline), 1 week, and 1 month postinjury in patients with either mTBI (n=46) or a comparison group with orthopedic injuries not involving the head (OI, n=29). The groups did not differ on preinjury resilience or mood status at baseline, but differed significantly on measures of anxiety and postconcussion symptom severity at each subsequent study occasion. Multivariate linear regression analyses were conducted to determine if preinjury resilience and mood were significant contributors to anxiety and postconcussion symptoms during the first month postinjury after accounting for other known host factors (e.g., age at injury, gender, and education). Injury group and preinjury mood status were significant predictors for all three dependent variables at each study occasion (all p<0.007). Preinjury resilience showed a positive trend only for acute stress severity at baseline, but demonstrated significant prediction of all three dependent measures at one week and one month postinjury. These results suggest that preinjury depressed mood and resilience are significant contributors to the severity of postinjury anxiety and postconcussion symptoms, even after accounting for effects of other specific host factors.

Exercise intolerance in individuals with postconcussion syndrome

CONTEXT

Little is known about exercise intolerance or the utility of an exercise evaluation in patients with postconcussion syndrome (PCS).

OBJECTIVE

To assess exercise intolerance in male and female patients with PCS.

DESIGN

Cross-sectional study.

SETTING

Laboratory setting.

PATIENTS OR OTHER PARTICIPANTS

Participants included a convenience sample of 34 patients with PCS (17 males, 17 females; age = 25.9 ± 10.9 years) and 22 uninjured individuals on whom we gathered historical deidentified laboratory data (control group; 11 males, 11 females; age = 23.3 ± 6.2 years).

MAIN OUTCOME MEASURE(S)

Self-reported symptoms, heart rate, systolic and diastolic blood pressures (BPs), and the Borg rating of perceived exertion were measured before, during each minute of, and immediately after a graded treadmill exercise test (Balke protocol). Exercise was stopped when participants could no longer maintain the effort or reported the onset of or increase in PCS symptoms.

RESULTS

Exercise test duration (8.5 ± 4.4 minutes versus 17.9 ± 3.6 minutes; t51 = 1.8, P < .001), heart rate (142.8 ± 24.1 versus 175.2 ± 17.4; t54 = -5.5, P < .001), and systolic BP (142.1 ± 18.3 mm Hg versus 155.5 ± 24.5 mm Hg; t53 = 2.3, P = .02) were lower, and diastolic BP (78.4 ± 10.2 mm Hg versus 73.5 ± 11.7 mm Hg; t53 = 2.2, P = .03) was higher at test cessation in the PCS than control group. Cox regression showed the odds of a shorter exercise duration were nearly 8 times greater in the PCS than control group (hazard ratio = 7.93; 95% confidence interval = 3.39, 18.56). In the general linear models that adjusted for differences in test duration, rating of perceived exertion was the only physiologic measure to show an overall difference between groups, with the control group reporting higher ratings than the PCS group (t53 = -6.0, P < .001). Within the PCS group, systolic BP was the only measure to show a sex effect, with males showing higher pressure readings than females throughout the exercise tests (t31 = 2.8, P = .009).

CONCLUSIONS

Patients with PCS had a symptom-limited response to exercise, and the treadmill test was a potentially useful tool to monitor the recovery from PCS.

The effect of varied test instructions on neuropsychological performance following mild traumatic brain injury: an investigation of "diagnosis threat"

Diagnosis threat is a psychosocial factor that has been proposed to contribute to poor outcomes following mild traumatic brain injury (mTBI). This threat is thought to impair the cognitive test performance of individuals with mTBI because of negative injury stereotypes. University students (N=45, 62.2% female) with a history of mTBI were randomly allocated to a diagnosis threat (DT; n=15), reduced threat (DT-reduced; n=15), or neutral (n=15) group. The reduced threat condition invoked a positive stereotype (i.e., that people with mTBI can perform well on cognitive tests). All participants were given neutral instructions before they completed baseline tests of objective cognitive function across a number of domains, psychological symptoms, and PCS symptoms, including self-reported cognitive and emotional difficulties. Participants then received either neutral, DT, or DT-reduced instructions before repeating the tests. Results were analyzed using separate mixed model analysis of variances (ANOVAs); one for each dependent measure. The only significant result was for the 2 × 3 ANOVA on an objective test of attention/working memory, Digit Span (p<0.05), such that the DT-reduced group performed better than the other groups, which were not different from each other. Although not consistent with predictions or earlier DT studies, the absence of group differences on most tests fits with several recent DT findings. The results of this study suggest that it is timely to reconsider the role of DT as a unique contributor to poor mTBI outcome.

Depression, anxiety, and stress as predictors of postconcussion-like symptoms in a non-clinical sample

This study examined the relationship between postconcussion-like symptoms and depressive symptoms, anxiety and stress respectively. Seventy-one university students with a negative concussion history completed the Depression Anxiety Stress Scales (DASS) and the British Columbia Postconcussion Symptom Inventory (BC-PSI). A multiple regression was conducted using the three DASS subscale scores as predictors of postconcussion-like symptoms. Depressive symptoms, anxiety and stress were significantly positively correlated with postconcussion-like symptoms at the bivariate level. When these three factors were examined together 72.9% of variance in BC-PSI total scores was explained overall. Stress and depressive symptoms emerged as significant multivariate predictors explaining 15% and 3% of unique variance, respectively. Anxiety was not a significant multivariate predictor. These results suggest that stress may be a more important predictor of postconcussion-like symptoms than previously identified. Findings are interpreted in light of Iverson (2012) conceptual model of poor outcomes from mild traumatic brain injury.

Rehabilitation of Concussion and Post-concussion Syndrome

CONTEXT

Prolonged symptoms after concussion are called post-concussion syndrome (PCS), which is a controversial disorder with a wide differential diagnosis.

EVIDENCE ACQUISITION

MEDLINE and PubMed searches were conducted for the years 1966 to 2011 using the search terms brain concussion/complications OR brain concussion/diagnosis OR brain concussion/therapy AND sports OR athletic injuries. Secondary search terms included post-concussion syndrome, trauma, symptoms, metabolic, sports medicine, cognitive behavioral therapy, treatment and rehabilitation. Additional articles were identified from the bibliographies of recent reviews.

RESULTS

Of 564 studies that fulfilled preliminary search criteria, 119 focused on the diagnosis, pathophysiology, and treatment/rehabilitation of concussion and PCS and formed the basis of this review. Rest is the primary treatment for the acute symptoms of concussion. Ongoing symptoms are either a prolonged version of the concussion pathophysiology or a manifestation of other processes, such as cervical injury, migraine headaches, depression, chronic pain, vestibular dysfunction, visual dysfunction, or some combination of conditions. The pathophysiology of ongoing symptoms from the original concussion injury may reflect multiple causes: anatomic, neurometabolic, and physiologic.

CONCLUSIONS

Treatment approaches depend on the clinician's ability to differentiate among the various conditions associated with PCS. Early education, cognitive behavioral therapy, and aerobic exercise therapy have shown efficacy in certain patients but have limitations of study design. An algorithm is presented to aid clinicians in the evaluation and treatment of concussion and PCS and in the return-to-activity decision.

Driving difficulties and adaptive strategies: the perception of individuals having sustained a mild traumatic brain injury

Introduction. After a mild traumatic brain injury (mTBI), individuals quickly resume driving. However, relatively little is known about the impact of mTBI on driving ability and, notably, on the perceived influence of postconcussive symptoms on driving. Hence, the objective of this study was to document the perception of driving abilities in individuals with mTBI. Method. Twenty-seven drivers with mTBI were interviewed to document their perception regarding their driving abilities. Both driving-related difficulties and compensatory strategies used to increase driving safety were documented. A mixed quantitative and qualitative analysis of the data was completed. Results. 93% of participants reported at least one difficulty perceived as having an impact on everyday activities. Most frequently named problems affecting driving were fatigue and reduced concentration. In addition, 74% of participants had adapted their driving or developed strategies to compensate for driving difficulties. Discussion/Conclusion. Postconcussive symptoms have repercussions on driving ability. However, people with mTBI tend to be aware of their difficulties and develop, over time, adaptive strategies. Preventive measures are thus warranted to increase health care professionals' awareness of the potential consequences of mTBI on driving ability and to promote guidelines for the safe resumption of driving after injury.

Cerebrovascular pathophysiology following mild traumatic brain injury

Mild traumatic brain injury (mTBI) or sport-induced concussion has recently become a prominent concern not only in the athletic setting (i.e. sports venue) but also in the general population. The majority of research to date has aimed at understanding the neurological and neuropsychological outcomes of injury as well as return-to-play guidelines. Remaining relatively unexamined has been the pathophysiological aspect of mTBI. Recent technological advances including transcranial Doppler ultrasound and near infrared spectroscopy have allowed researchers to examine the systemic effects of mTBI from rest to exercise, and during both asymptomatic and symptomatic conditions. In this review, we focus on the current research available from both human and experimental (animal) studies surrounding the pathophysiology of mTBI. First, the quest for a unified definition of mTBI, its historical development and implications for future research is discussed. Finally, the impact of mTBI on the control and regulation of cerebral blood flow, cerebrovascular reactivity, cerebral oxygenation and neuroautonomic cardiovascular regulation, all of which may be compromised with mTBI, is discussed.

A preliminary study of subsymptom threshold exercise training for refractory post-concussion syndrome

OBJECTIVE

To evaluate the safety and effectiveness of subsymptom threshold exercise training for the treatment of post-concussion syndrome (PCS).

DESIGN

Prospective case series.

SETTING

University Sports Medicine Concussion Clinic.

PARTICIPANTS

Twelve refractory patients with PCS (6 athletes and 6 nonathletes).

INTERVENTION

Treadmill test to symptom exacerbation threshold (ST) before and after 2 to 3 weeks of baseline. Subjects then exercised 5 to 6 days per week at 80% ST heart rate (HR) until voluntary peak exertion without symptom exacerbation. Treadmill testing was repeated every 3 weeks.

MAIN OUTCOME MEASURES

Adverse reactions to exercise, PCS symptoms, HR, systolic blood pressure (SBP), achievement of maximal exertion, and return to work/sport.

RESULTS

Pretreatment, ST occurred at low exercise HR (147 + or - 27 bpm) and SBP (142 + or - 6 mm Hg). After treatment, subjects exercised longer (9.75 + or - 6.38 minutes to 18.67 + or - 2.53 minutes, P = .001) and achieved peak HR (179 + or - 17 bpm) and SBP (156 + or - 13 mm Hg), both P < .001 versus pretreatment, without symptom exacerbation. Time series analysis showed significant change in rate of symptom reduction for all subjects and reduced mean symptom number in 8/11. Rate of PCS symptom improvement was related to peak exercise HR (r = -0.55, P = .04). Athletes recovered faster than nonathletes (25 + or - 8.7 vs 74.8 + or - 27.2 days, P = .01). No adverse events were reported. Athletes returned to sport and nonathletes to work.

CONCLUSIONS

Treatment with controlled exercise is a safe program that appears to improve PCS symptoms when compared with a no-treatment baseline. A randomized controlled study is warranted.

Validation of the Behavioral Dyscontrol Scale-Electronic Version: Sensitivity to subtle sequelae of mild traumatic brain injury

PRIMARY OBJECTIVE

To determine whether a new computer-administered battery (Behavioral Dyscontrol Scale-Electronic Version; BDS-EV) can detect subtle executive weaknesses among individuals with a self-reported history of mild head trauma (MHT), and to compare the utility of this battery to the original, non-electronic BDS and other traditional executive measures. Both BDS-EV and BDS are comprised of three factors (motor programming, environmental independence, and fluid intelligence).

METHOD

Participants with (n = 19) and without (n = 24) MHT were compared on their performance on the BDS-EV, the non-electronic BDS, and three traditional measures of executive abilities.

RESULTS

Participants with MHT differed from those without MHT on the BDS-EV motor programming and environmental independence, but not on any other measures.

CONCLUSION

The results show that electronic administration improved the sensitivity of the battery, and support prior findings that traditional executive measures are generally insensitive to subtle executive deficits associated with chronic MHT.

Concussion in sports: postconcussive activity levels, symptoms, and neurocognitive performance

CONTEXT

Evidence suggests that athletes engaging in high-intensity activities after concussion have more difficulties with cognitive recovery.

OBJECTIVE

To examine the role postinjury activity level plays in postconcussive symptoms and performance on neurocognitive tests in a population of student-athletes.

DESIGN

Retrospective cohort study with repeated measures of neurocognitive performance and symptom reporting.

SETTING

University-based sports concussion clinic.

PATIENTS OR OTHER PARTICIPANTS

Ninety-five student-athletes (80 males, 15 females: age = 15.88 +/- 1.35 years) were retrospectively assigned to 1 of 5 groups based on a postinjury activity intensity scale.

MAIN OUTCOME MEASURE(S)

We employed a regression analysis for repeated measures to evaluate the relationship of activity intensity to symptoms and neurocognitive outcome up to 33 days after concussion. Postconcussion symptom scores and neurocognitive (verbal memory, visual memory, visual motor speed, and reaction time) scores served as the primary outcome measures.

RESULTS

Level of exertion was significantly related to all outcome variables (P < .02 for all comparisons). With multivariate analysis, activity intensity remained significant with respect to visual memory (P = .003) and reaction time (P < .001).

CONCLUSIONS

Activity level after concussion affected symptoms and neurocognitive recovery. Athletes engaging in high levels of activity after concussion demonstrated worse neurocognitive performance. For these tasks, those engaging in moderate levels of activity demonstrated the best performance.

Utility of the UFOV test with mild traumatic brain injury

Driving skills are socially important, easily disrupted by brain injury, and potentially risky and difficult to evaluate afterward. The Useful Field of View test has seen successful use with severe traumatic brain injury (TBI), but its use with mild TBI victims has not been examined. This study shows its ecological insensitivity among persons with mild TBI or no impairment and suggests its use be limited to more severely impaired persons.

Correlates of persistent postconcussional disorder: DSM-IV criteria versus ICD-10

Controversy surrounding the causation of symptom complaints after mild traumatic brain injury (MTBI) is reflected by the existence of alternative diagnostic criteria for postconcussional syndrome (PCS) in the International Classification of Diseases (ICD) and postconcussional disorder (PCD) in the Diagnostic and Statistical Manual of Mental Disorders-4th edition (DSM-IV). Previous studies of persisting symptoms have employed various symptom checklists rather than uniform criteria-based diagnoses. This is the first prospective study of persisting symptom complaints using the formal diagnostic criteria for PCD and PCS and comparing these criteria sets in terms of prevalence, relationship to potential compensation, and emotional/functional status. In this prospective study, an unselected series of adults with uncomplicated MTBI (N = 139) was assessed at 6 months postinjury with a brief neuropsychological battery and measures of psychiatric symptoms/disorders, social support/community integration, health-related quality of life, and global outcome. In parallel analyses, participants with PCD/PCS were compared to those without the disorder. Potential compensation was an equally significant factor in both criteria sets. Persistent PCS criteria were met 3.1 times more frequently than persistent PCD criteria. Significant racial differences in fulfilling PCD/PCS criteria were found. No differences in emotional/functional status patterns or global outcome were found between the criteria sets except for minor dissimilarities in the social/community integration domain. The results demonstrate that despite large differences in the frequency of patients meeting the two diagnostic criteria sets, a clear basis for preferring either the PCD or PCS criteria remains to be determined.