Nocebo Effects in Concussion: Is All That Is Told Beneficial?

Functional Neurological Disorder Presenting After Concussion: A Retrospective Case Series

OBJECTIVE

Although a majority of individuals recover from a concussion within weeks of the index injury, a substantial minority of patients report persistent postconcussion symptoms. Some of these symptoms may reflect a diagnosis of functional neurological disorder (FND). The authors evaluated the relationship between persistent postconcussion symptoms and FND symptoms.

METHODS

In this retrospective chart review, the authors characterized demographic and clinical information from 50 patients with a confirmed diagnosis of FND whose functional neurological symptoms started after a concussion.

RESULTS

Patients who developed FND after a concussion had high rates of baseline risk factors for both persistent postconcussion symptoms and FND. After the concussive event, functional neurological symptoms presented abruptly or developed insidiously over time. Functional neurological symptoms ranged widely and included gait symptoms, seizures, speech and language symptoms, weakness, sensory symptoms, tremors, and vision and oculomotor symptoms.

CONCLUSIONS

Functional neurological symptoms can arise after a concussion. FND should be considered in the differential diagnosis of individuals presenting with neurological symptoms beginning after a concussion. By failing to recognize functional symptoms, clinicians may inadvertently reinforce negative health-related beliefs regarding a patient's injured brain.

The Postconcussion Syndrome and Posttraumatic Headaches in Civilians, Soldiers, and Athletes

Posttraumatic headaches are one of the most common and controversial secondary headache types. After a mild traumatic brain, an estimated 11% to 82% of people develop a postconcussion syndrome, which has been controversial for more than 160 years. Headache is estimated as present in 30% to 90% of patients after a mild head injury. Most headaches are tension-type-like or migraine-like. Headaches in civilians, soldiers, athletes, and postcraniotomy are reviewed. The treatments are the same as for the primary headaches. Persistent posttraumatic headaches can continue for many years.

Healthcare perceptions of persons with traumatic brain injuries across providers: shortcomings in the chronic phase of care

OBJECTIVE

This investigation sought to examine the perceptions of individuals with mild, moderate, and severe traumatic brain injury (TBIs) toward healthcare providers across rehabilitation contexts (acute, rehabilitation, and chronic).

METHODS

The mCARE-TBI survey was distributed via Qualtrics throughout the US and Canada. Sixty-four survey responses met criteria for analysis. Participants were ≥18 years old, one-year post onset, reported no unrelated neurological deficits prior to the single TBI, and reported no prior diagnosed psychiatric disorders. The mCARE was the primary outcome measure. Comparisons were made between provider ratings on each question.

RESULTS

Significant differences were found between chronic-phase care, compared to acute care and rehabilitation. Group differences were found in transitioning home after discharge and in between each therapy discipline and both nurses and doctors, as well as for really listening and pairwise differences between therapy disciplines and both nurses and doctors. Group effects were found for showing compassion and care and being positive.

CONCLUSIONS

All disciplines need to improve communication, and transition care/discharge planning. Dismissal of ongoing impairments continues to be an area of perceived concern with doctors in particular. Communication training is needed, particularly for nurses and doctors.

The Nocebo Effect: A Bias in Clinical Practice-An Ethical Approach

BACKGROUND

The nocebo effect is often disregarded in medical practice and is certainly much less known than the placebo effect, although, in reality, both can influence therapeutic decision making and the quality of life of patients. However, the nocebo effect raises a number of issues not only of a practical nature related to clinical activity but also ethical dilemmas related to the observance of the patient's autonomy, nonmaleficence, or informed consent and the information on which it is based.

AREAS OF UNCERTAINTY

The ethical dilemmas raised by the nocebo effect revolve around how informed consent can be achieved, the accuracy and volume of information that is transmitted to the patient, and how to report negative side effects of therapeutic treatment.

DATA SOURCES

In September 2023, a narrative analysis of the literature was conducted using a combination of keywords such as nocebo, placebo, ethics, therapeutic relationship from PubMed, Scopus, Google Scholar, and so on, as well as from official documents developed at an international level (World Health Organization), for a period of 10 years (2012-2021).

RESULTS

Analyzing the articles that remarked upon the significant impact of ethics in nocebo research or in the therapeutic relationship, we can state that the existence of several relevant issues of interest have been detected regarding the ethical use of nocebo and its impact in research or in clinics and thus the need for proper knowledge and management of the impact of nocebo effects. The ethical paradox of obtaining informed consent with the 2 goals, first, the need for complete information and second, the preservation of the autonomy of the patient, respectively, that of "primum non-nocere" and of avoiding unnecessary harm by revealing probable adverse effects is a point of interest for numerous studies. The potential for a nocebo effect is present when we inform patients about the risks and benefits of treatment, there being a clear link between the moral and ethical duty to inform patients and the need to avoid situations that increase the nocebo impact on how the disease or the adverse effects of the treatment are perceived. Adapting information about the side effects of medicines should focus on ensuring a balance between transparency and caution, especially in patients with a high potential for nocebo effect.

CONCLUSIONS

The nocebo effect had for a long time been unknown or denied, although it can interfere with the results of the treatment used. As the nocebo phenomenon becomes increasingly known in medical practice, the clinical and ethical implications are identified by medical staff, and nocebo's adverse responses are no longer ignored.

Collegiate student-athletes concussion knowledge and attitudes: what a difference a decade Makes

OBJECTIVE

The purpose of this study was to assess changes in concussion knowledge and attitudes amongst incoming intercollegiate student-athletes over the course of a decade (2010-2012 vs 2021-2023).

METHODS

There were 592 student-athletes from 2 cohorts (2010-2012, 2021-2023) who completed the Rosenbaum Concussion Knowledge and Attitudes Survey (ROCKaS) questionnaire which is comprised of a concussion knowledge index (CKI, 0-24) and attitude index (CAI, 15-75) with higher scores reflecting better performance. A three factor ANOVA (Group, Sex, Concussion History) compared performance on the CKI and CAI. Individual questions were compared between groups with a Chi-Square analysis.

RESULTS

For the CKI, there was a significant main effect for Group (2010-2012: 18.5 ± 2.6, 2021-2023: 19.4 ± 2.5, p < 0.001, η 2 = 0.032 ) . For the CAI, there was also a significant main effect for group (2010-2012: 52.9 ± 6.0, 2021-2023: 62.2 ± 6.5, p < 0.001, η 2 = 0.359 ) .

CONCLUSIONS

The results of this study show a modest increase in concussion knowledge; however, large improvements in concussion attitudes were observed between groups. These results suggest a continued improvement in student-athlete concussion awareness and provide specific areas to continue addressing persistent misconceptions.

Factors perpetuating functional cognitive symptoms after mild traumatic brain injury

INTRODUCTION

Self-reported memory difficulties (forgetting familiar names, misplacing objects) often persist long after a mild traumatic brain injury (mTBI), despite normal neuropsychological test performance. This clinical presentation may be a manifestation of a functional cognitive disorder (FCD). Several mechanisms underlying FCD have been proposed, including metacognitive impairment, memory perfectionism, and misdirected attention, as well as depression or anxiety-related explanations. This study aims to explore these candidate perpetuating factors in mTBI, to advance our understanding of why memory symptoms frequently persist following mTBI.

METHODS

A cross-sectional study of 67 adults (n = 39 with mTBI mean = 25 months ago and n = 28 healthy controls). Participants completed standardized questionnaires (including the Functional Memory Disorder Inventory), a metacognitive task (to quantify discrepancies between their trial-by-trial accuracy and confidence), and a brief neuropsychological test battery. We assessed candidate mechanisms in two ways: (1) between-groups, comparing participants with mTBI to healthy controls, and (2) within-group, examining their associations with functional memory symptom severity (FMDI) in the mTBI group.

RESULTS

Participants with mTBI performed similarly to controls on objective measures of memory ability but reported experiencing much more frequent memory lapses in daily life. Contrary to expectations, metacognitive efficiency did not differentiate the mTBI and control groups and was not associated with functional memory symptoms. Memory perfectionism was strongly associated with greater functional memory symptoms among participants with mTBI but did not differ between groups when accounting for age. Depression and checking behaviors produced consistent results across between-groups and within-group analyses: these factors were greater in the mTBI group compared to the control group and were associated with greater functional memory symptoms within the mTBI group.

CONCLUSIONS

This study highlights promising (e.g., depression, checking behaviors) and unlikely (e.g., metacognitive impairment) mechanisms underlying functional memory symptoms after mTBI, to guide future research and treatment.

Improving outcome after paediatric concussion: challenges and possibilities

The term concussion has permeated mainstream media and household vocabulary mainly due to awareness regarding the risks of concussion in professional contact sports, yet it occurs across a variety of settings and ages. Concussion is prevalent in infants, preschoolers, children, and adolescents, and is a common presentation or reason for referral to primary care providers, emergency departments, and specialised trauma clinics. Its broad range of symptoms and sequelae vary according to multiple individual, environmental, and clinical factors and can lead to health and economic burden. More than 20 years of research into risk factors and consequences of paediatric concussion has revealed as many questions as answers, and scientific work and clinical cases continue to expose its complexity and heterogeneity. In this Review, we present empirical evidence for improving outcome after paediatric concussion. We consider work pertaining to both sports and other injury mechanisms to provide a perspective that should be viewed as complementary to publications focused specifically on sports concussion. Contemporary challenges in prevention, diagnosis, prognosis, and intervention are discussed alongside pathways and future directions for improving outcome.

Concussion Rehabilitation and the Application of Ten Movement Training Principles

Concussion awareness continues to grow in all aspects of healthcare, including the areas of prevention, acute care, and ongoing rehabilitation. Most of the concussion research to date has focussed on the challenges around screening and diagnosing what can be a complex mix of brain impairments that overlay with additional pre-existing comorbidities. While we expect further progress in concussion diagnosis, progress also continues to be made around proactive rehabilitation, with the emergence of interventions that can enhance the recovery process, maximise function and independence with a return to study, work, and play. Traditionally, optimal multimodal assessments of concussion have treated the physical, cognitive, and psychological domains of brain injury separately, which supports diagnosis, and informs appropriate follow-up care. Due to the complex nature of brain injury, multimodal assessments direct care toward professionals from many different disciplines including medicine, physiotherapy, psychology, neuropsychology, ophthalmology, and exercise physiology. In addition, these professionals may work in different fields such as sports, neurorehabilitation, vestibular, musculoskeletal, community, vocational, and general practice clinical settings. Rehabilitation interventions for concussions employed in practice are also likely to use a blend of theoretical principles from motor control, cognitive, and psychological sciences. This scale of diversity can make information dissemination, collaboration, and innovation challenging. The Ten Movement Training Principles (MTPs) have been proposed as a usable and relevant concept to guide and support clinical reasoning in neurorehabilitation. When applied to concussion rehabilitation, these same 10 principles provide a comprehensive overview of key rehabilitation strategies for current and future practice. Future collaborations can use these training principles to support clinical and research innovations including the rapid rise of technologies in this growing field of rehabilitation practice.

"I Avoid Interactions With Medical Professionals as Much as Possible Now": Health Care Experiences of Individuals With Traumatic Brain Injuries

PURPOSE

This study examined the perceptions of health care experiences by individuals with traumatic brain injuries (TBIs) across the recovery continuum, regarding care received by a variety of health care providers following their TBI. It sought to identify whether perceptions differed across mild, moderate, and severe participants, as well as acute, subacute, and chronic recovery.

METHOD

Eighteen individuals with TBI were interviewed, using the Sydney Psychosocial Reintegration Scale-Second Edition (SPRS-2) and a semistructured interview about health care perceptions. A qualitative investigation employing two methods, interpretive phenomenological analysis (IPA) and Systemic Functional Linguistics (SFL; modality and appraisal analysis), provided a micro and macrolevel discourse analysis.

RESULTS

IPA analyses of SPRS-2 interviews differed across severity levels but included changes to relationships, identity, and changes to social engagement and activity. IPA results revealed three core themes related to the health care experiences across severity that encompassed (a) frustrations with providers and (b) lack of support in the chronic phase, and (c) that finding support is crucial. SFL results provided insight into how individuals appraised such experiences in light of their identity and personal perspectives. Key differences between individuals with mild, moderate, and severe TBI diagnoses were found, with those who experienced a mild TBI expressing the most discontent with services received. Participants were most satisfied with acute care and least satisfied with chronic phase support.

CONCLUSIONS

The results of this study have significant implications for health care professionals interacting with individuals who have experienced a TBI. Facilitating improved communication, referrals, increased access to mental health counseling, and resources such as groups to support identity expression could improve the health care experience.

Motor vehicle crash concussion mechanism displays a greater total number of symptoms and greater affective symptom severity but no neurocognitive differences compared with sport-related concussion mechanism

Previous research among adolescents has shown differences in symptoms and neurocognitive performance between sport-related (SRC) and motor vehicle crash (MVC) concussion mechanisms. Limited research has focused on young adults. The purpose of our study was to compare symptoms, balance, and neurocognitive performance between SRC and MVC mechanisms in young adults. Forty-three (58.1% female, age = 25.5 ± 3.2 years, days since concussion = 12.8 ± 12.7) and 26 (76.9% female, age = 24.1 ± 5.6 years, days since concussion = 12.6 ± 8.3) individuals with an SRC and MVC mechanism, respectively, participated. Primary outcome measures included the total number, severity, cluster (disorientation, migraine, lethargy, and affective) of post-concussion symptoms endorsed, Balance Error Scoring System (BESS), and CNS Vital Signs scores. Clusters are subgroups of symptoms used for targeted rehabilitation. We used independent t-tests and Mann-Whitney U tests to compare symptoms, BESS, and neurocognitive performance. Cliff's Delta effect size was interpreted as negligible (<0.15), small (0.15-0.33), medium (0.34-0.47), and large (≥0.48). There were no group differences for any demographic factors or preexisting conditions (p-range = 0.112-0.991). Participants with an MVC mechanism reported a greater number of total post-concussion symptoms (p = 0.025, Cliff's Delta = 0.32) and a more severe affective symptom cluster (p = 0.010, Cliff's Delta = 0.37). There were no group differences for BESS or neurocognitive performance after correcting for multiple comparisons. The MVC mechanism resulted in a greater total symptom burden relative to the SRC mechanism. Medical practitioners and individuals experiencing a concussion should know that concussions are heterogeneous within and across various mechanisms.

Psychological Contributions to Symptom Provocation Testing After Concussion

OBJECTIVE

Following concussion, symptoms such as headache, dizziness, and fatigue may transiently worsen or reemerge with increased exertion or activity. Standardized tests have been developed to assess symptom increases following aerobic, cognitive, or vestibular/oculomotor challenge. Although neurophysiological mechanisms are proposed to underlie symptom increases following exertion, psychological factors such as anxiety and misinterpretation of normal bodily sensations may also play a role. In this study, we examined the contribution of psychological factors to symptom provocation testing outcomes.

SETTING

Two outpatient concussion clinics in British Columbia, Canada.

PARTICIPANTS

Adults with persistent symptoms following concussion ( N = 79; 62% women).

DESIGN

In a single session, participants completed self-report questionnaires measuring the psychological factors of interest and underwent symptom provocation testing including aerobic (Buffalo Concussion Bike Test; BCBT), cognitive (National Institutes of Health Toolbox-Cognition Battery; NIHTB-CB), and vestibular/oculomotor (Vestibular/Ocular Motor Screening for Concussion; VOMS) challenge.

MAIN MEASURES

Psychological factors of interest included premorbid and current anxiety (Generalized Anxiety Disorder-7; GAD-7), catastrophizing (Pain Catastrophizing Scale-Adapted; PCS-A), fear avoidance behavior (Fear Avoidance Behavior after Traumatic Brain Injury; FAB-TBI), and somatization (Patient Health Questionnaire-15; PHQ-15). Our primary outcome variables were self-reported symptom change during each symptom provocation test.

RESULTS

We found that current anxiety ( B = 0.034; 95% CI = 0.003, 0.065), symptom catastrophizing ( B = 0.013; 95% CI = 0.000, 0.026), fear avoidance behavior ( B = 0.029; 95% CI = 0.008, 0.050), and somatization ( B = 0.041; 95% CI = 0.007, 0.075) were associated with increased symptoms during the VOMS in univariate models adjusted for time postinjury but not in a multivariable model that included all covariates. The psychological variables of interest were not significantly related to symptom change during the BCBT or NIHTB-CB.

CONCLUSION

Our findings suggest that symptom provocation test failure should be interpreted with caution because it might indicate psychological maladjustment rather than lingering brain injury or incomplete neurophysiological recovery.

Post-Concussion Symptoms and Disability in Adults with Mild Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Studies investigating long-term symptoms and disability after mild traumatic brain injury (mTBI) have yielded mixed results. This systematic review and meta-analysis aimed to determine the prevalence of self-reported post-concussion symptoms (PCS) and disability following mTBI. We systematically searched MEDLINE, Embase, CINAHL, CENTRAL, and PsycInfo to identify inception cohort studies of adults with mTBI. Paired reviewers independently extracted data and assessed risk of bias with the Scottish Intercollegiate Guidelines Network criteria. We identified 43 eligible studies for the systematic review; 41 were rated as high risk of bias, primarily due to high attrition (> 20%). Twenty-one studies (49%) were included in the meta-analyses (five studies were narratively synthesized; 17 studies were duplicate reports). At 3-6 months post-injury, the estimated prevalence of PCS from random-effects meta-analyses was 31.3% (95% confidence interval [CI] = 25.4-38.4) using a lenient definition of PCS (2-4 mild severity PCS) and 18.3% (95% CI = 13.6-24.0) using a more stringent definition. The estimated prevalence of disability was 54.0% (95% CI = 49.4-58.6) and 29.6% (95% CI = 27.8-31.5) when defined as Glasgow Outcome Scale-Extended <8 and <7, respectively. The prevalence of symptoms similar to PCS was higher in adults with mTBI versus orthopedic injury (prevalence ratio = 1.57, 95% CI = 1.22-2.02). In a meta-regression, attrition rate was the only study-related factor significantly associated with higher estimated prevalence of PCS. Setting attrition to 0%, the estimated prevalence of PCS (lenient definition) was 16.1%. We conclude that nearly one in three adults who present to an emergency department or trauma center with mTBI report at least mild severity PCS 3-6 months later, but controlling for attrition bias, the true prevalence may be one in six. Studies with representative samples and high retention rates are needed.

Interdisciplinary Rehabilitation for Concussion Recovery (i-RECOveR): protocol of an investigator-blinded, randomised, case series with multiple baseline design to evaluate the feasibility and preliminary efficacy of a 12-week treatment for persistent post-concussion symptoms

BACKGROUND

Up to 25% of concussed individuals experience persistent post-concussion symptoms (PPCSs) which may interfere with the return to pre-injury activities and cause significant stress. Given that multiple etiological factors are thought to contribute to PPCSs, an interdisciplinary approach is recommended. This pilot study aims to primarily investigate the feasibility of a novel interdisciplinary treatment for PPCSs. Given this intervention is novel, uncertainty exists in terms of potential recruitment and retention rates, adverse events, and treatment adherence and fidelity. These factors will be explored to inform the feasibility of a phase-2 randomised controlled trial. Preliminary efficacy of this intervention will also be explored.

METHODS

Fifteen individuals with mild traumatic brain injury and PPCSs will receive up to 12 weeks of interdisciplinary treatments including psychology, physiotherapy, and medical interventions. Primary feasibility outcomes including data on recruitment and retention rates and treatment adherence will be explored descriptively. The cognitive therapy rating scale will be used to assess treatment fidelity. A single-case series with multiple baseline design will be used to explore preliminary efficacy. Participants will be randomly assigned to baseline phases of 2, 4, or 6 weeks. Regarding patient-centred secondary outcomes, the Rivermead Post-Concussion Symptoms Questionnaire will be assessed three times a week during baseline and treatment phases. Secondary outcomes also include measures of mood, sleep and fatigue, physical functioning, return to activity, and health-related quality of life. Patient-centred outcomes will be assessed at baseline, pretreatment, post-treatment, and one- and three-month follow-up. Thematic analysis of participant experiences will be explored through qualitative interviews.

DISCUSSION

Results from this trial will inform the feasibility and preliminary efficacy of this interdisciplinary concussion intervention and whether proceeding to a future definitive phase-2 randomised controlled trial is worthwhile. Understanding the end-user perspective of the treatment will also enable modifications to the treatment protocol for future trials to best suit the needs of individuals with PPCSs after mTBI. Outcomes from this trial can be directly translated into community rehabilitation programmes.

TRIAL REGISTRATION

ANZCTR, ACTRN12620001111965. Registered 27 October 2020, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=379118.

Turning away from sound: The role of fear avoidance in noise sensitivity following mild traumatic brain injury

BACKGROUND

Noise sensitivity (NS) following mild traumatic brain injury (mTBI) is common impacts functioning and outcomes. Recent research suggests psychological factors may have a significant role in the development of NS after mTBI. Psychological interventions have been advocated for to reduce this experience. To be effective, these interventions must aim to target the psychological processes that contribute to this relationship. Fear avoidance holds promise in this regard. The current study aimed to explore the role of fear avoidance in NS and examine its role in mediating the relationship between psychological distress and NS.

METHOD

Adults (n = 234) diagnosed with mTBI were recruited from outpatient mTBI clinics throughout New Zealand. Participants completed self-report measures of pre-injury mental health status, as well as current post-concussion symptoms, psychological distress (anxiety, stress, depression, fear avoidance and post-traumatic stress symptoms) and functional status upon entry to an mTBI outpatient clinic (M = 8.9, SD = 9.2, post injury).

RESULTS

A pre-injury mental health diagnosis was associated with NS after mTBI, as were symptoms of anxiety, stress, depression, and post-traumatic stress. Regression analyses revealed that fear avoidance (β = 0.45, p = .01), as well as stress (β = 0.07, p = .01) and PTSD symptoms (β = 0.02, p = .01), made a significant and unique contribution to NS. A series of mediation analyses found that fear avoidance had a significant indirect effect on the relationships between psychological distress and NS.

CONCLUSIONS

Fear avoidance is related to NS following mTBI. Targeting fear avoidance behaviours and beliefs may represent a treatment target for reducing NS after mTBI.

Placebo effect in pharmacological management of fibromyalgia: a meta-analysis

INTRODUCTION

The management of fibromyalgia involves a combination of pharmacological and non-pharmacological treatments.

SOURCE OF DATA

Recently published literature in PubMed, Google Scholar and Embase databases.

AREAS OF AGREEMENT

Several pharmacological and non-pharmacological strategies have been proposed for the management of fibromyalgia. However, the management of fibromyalgia remains controversial. The administration of placebo has proved to be more effective than no treatment in many clinical settings and evidence supports the 'therapeutic' effects of placebo on a wide range of symptoms.

AREAS OF CONTROVERSY

The placebo effect is believed to impact the clinical outcomes, but its actual magnitude is controversial.

GROWING POINTS

A meta-analysis comparing pharmacological management versus placebo administration for fibromyalgia was conducted.

AREAS TIMELY FOR DEVELOPING RESEARCH

Drug treatment resulted to be more effective than placebo administration for the management of fibromyalgia. Nevertheless, placebo showed a beneficial effect in patients with fibromyalgia. Treatment-related adverse events occurred more frequently in the drug treatment.

LEVEL OF EVIDENCE

I, Bayesian network meta-analysis of double-blind randomized clinical trials.

Psychological flexibility in mild traumatic brain injury: an evaluation of measures

PRIMARY OBJECTIVE

In this study, we examined the psychometric properties of measures of psychological flexibility in a mild traumatic brain injury (mTBI) sample.

METHOD AND PROCEDURES

Adults who sustained a mTBI (n = 112) completed the Acceptance and Action Questionnaire - Acquired Brain Injury reactive avoidance subscale (AAQ-ABI (RA). Exploratory factor analysis and Rasch analysis were conducted to evaluate the facture structure, dimensionality, and differential item functioning. Construct validity was determined by correlating the AAQ-ABI (RA) with the Acceptance and Action Questionnaire-Revised (AAQ-II) and Fear Avoidance after Traumatic Brain Injury (FAB-TBI).

MAIN OUTCOME AND RESULTS

The AAQ-ABI (RA) was found to have strong internal consistency (Cronbach's α = 0.87). Consistent with previous findings, the AAQ-ABI (RA) had one distinct factor. Fit to the unidimensional Rasch model was adequate (χ² (18) = 22.5, p = .21) with no evidence of differential item functioning across person factors examined. The AAQ-ABI (RA) also had expected relationships with theoretically relevant constructs.

CONCLUSIONS

The AAQ-ABI (RA) appears to be a psychometrically sound measure of psychological flexibility in mTBI.

Examining Criteria for Defining Persistent Post-concussion Symptoms in Children and Adolescents

Researchers operationalize persistent post-concussion symptoms in children and adolescents using varied definitions. Many pre-existing conditions, personal characteristics, and current health issues can affect symptom endorsement rates in the absence of, or in combination with, a recent concussion, and the use of varied definitions can lead to differences in conclusions about persistent symptoms and recovery across studies. This study examined how endorsement rates varied by 14 different operational definitions of persistent post-concussion symptoms for uninjured boys and girls with and without pre-existing or current health problems. This cross-sectional study included a large sample (age range: 11–18) of girls (n = 21,923) and boys (n = 26,556) without a recent concussion who completed the Post-Concussion Symptom Scale at preseason baseline. Endorsements rates varied substantially by definition, health history, and current health issues. The most lenient definition (i.e., a single mild symptom) was endorsed by most participants (54.5% of boys/65.3% of girls). A large portion of participants with pre-existing mental health problems (42.7% of boys/51.5% of girls), current moderate psychological distress (70.9% of boys/72.4% of girls), and insufficient sleep prior to testing (33.4% of boys/47.6% of girls) endorsed symptoms consistent with mild ICD-10 postconcussional syndrome; whereas participants with no current or prior health problems rarely met this definition (1.6% of boys/1.6% of girls). The results illustrate the tremendous variability in the case definitions of persistent symptoms and the importance of harmonizing definitions across future studies.

Premortem Chronic Traumatic Encephalopathy Diagnoses in Professional Football

OBJECTIVE

American-style football (ASF) has gained attention because of possible links between repetitive head injury and neurodegenerative diseases. Although postmortem pathologic changes consistent with chronic traumatic encephalopathy (CTE) have been reported in ASF players, there are currently no established premortem diagnostic criteria for CTE. Nevertheless, presented with symptoms of cognitive impairment, clinicians treating former players may be inclined to suggest CTE without a thorough exploration of comorbid factors that demonstrate similar clinical phenotypes to putative CTE.

METHODS

A survey of 3,913 former ASF players aged 24 to 89 was conducted for those who responded by March 2019.

RESULTS

Despite being a postmortem diagnosis, 108 players (2.8%) self-reported clinician-diagnosed CTE. The percentage of players under age 60 years reporting a CTE diagnosis was 2.3% versus 3.7% in participants age 60 or older. Comorbidities in participants self-reporting CTE were significantly more common, including sleep apnea, hypercholesterolemia, obesity, indicators of past or current depression, hypertension, prescription pain medication use, heart conditions, and low testosterone when compared to non-CTE respondents. Patterns of reporting for obesity, hypertension, heart conditions, or hypercholesterolemia differed between older and younger participants. Cognitive impairment symptoms were significantly higher in participants self-reporting CTE.

INTERPRETATION

Some former professional football players have been clinically diagnosed with CTE, a postmortem condition. Comorbidities that can affect cognition were associated with CTE diagnoses in both older and younger players. Although underlying neuropathology cannot be ruled out, treatable conditions should be explored in former athletes demonstrating CTE-linked clinical phenotypes or symptoms as a means of improving cognitive health in these patients. ANN NEUROL 2020 ANN NEUROL 2020;88:106-112.

Persistent post-concussive symptoms: A model of predisposing, precipitating, and perpetuating factors

While the majority of individuals make full recovery within a short period following mild traumatic brain injury (mTBI), some continue to experience a more chronic course of symptoms termed persistent post-concussive symptoms (PPCS). Previous models and conceptualizations of PPCS have typically not differentiated the time at which factors present across the injury timeline spectrum or have considered a limited array of contributory factors. In the current review, PPCS are examined within the predisposing, precipitating, and perpetuating (PPP) model, which has been applied to explain other syndromes resulting in a clear framework to explain, disseminate, and further research the specified condition. Previous PPCS models are reviewed and integrated into this comprehensive model, as well. To do so, a literature review was completed which included previous PPP models applied to other conditions, other PPCS models, and more recent findings of factors related to PPCS. This new iteration and application of the PPP model more clearly, completely, and validly identifies contributing factors to PPCS. Future prevention, early identification, clearer questions for future research, and treatment of PPCS is possible with clarity provided by this model.