Associations between interpersonal violence victimisation and concussions among US college students

Interpersonal violence is common on college campuses and is associated with many adverse health outcomes; however, it remains unknown whether experiencing interpersonal violence victimisation is associated with concussions. The aim of this study was to estimate the associations between interpersonal violence, including emotional abuse, physical abuse and sexual assault, and concussions among a large, diverse sample of college students. We analysed cross-sectional data from the 2018–2019 national (US) Healthy Minds Study (N = 1,478). Multiple logistic regression analyses were conducted to estimate the association between interpersonal violence victimisation (any violence victimisation, emotional abuse, physical abuse and sexual assault) and concussion history (any concussion, diagnosed concussion and undiagnosed concussion), while adjusting for potential confounders. Analyses were conducted among the overall sample and separately by male and female participants. Results showed patterns of significant associations between interpersonal violence victimisation and concussions among the overall sample and among male and female participants. Among the overall sample, any interpersonal violence victimisation (adjusted odds ratio [AOR] 1.45, 95% confidence interval [CI] 1.13–1.88), emotional abuse (AOR 1.36, 95% CI 1.06–1.76), physical abuse (AOR 1.61, 95% CI 1.07–2.44) and sexual assault (AOR 2.17, 95% CI 1.44–3.26) were associated with higher odds of any concussion history. Sexual assault victimisation had the strongest association with any concussion history among male (AOR 1.96, 95% CI 1.04–3.71) and female (AOR 2.96, 95% CI 1.62–5.43) participants. These results expand on prior interpersonal violence and concussion research by showing an association with multiple victimisation measures among a large and diverse sample of college students. Medical professionals should screen for concussions among college students who experience emotional abuse, physical abuse and sexual assault to provide appropriate guidance. Information on the symptoms of concussions should be incorporated into campus violence awareness and prevention efforts.     

In vivo characterization of chronic traumatic encephalopathy using [F-18]FDDNP PET brain imaging

Chronic traumatic encephalopathy (CTE) is an acquired primary tauopathy with a variety of cognitive, behavioral, and motor symptoms linked to cumulative brain damage sustained from single, episodic, or repetitive traumatic brain injury (TBI). No definitive clinical diagnosis for this condition exists. In this work, we used [F-18]FDDNP PET to detect brain patterns of neuropathology distribution in retired professional American football players with suspected CTE (n = 14) and compared results with those of cognitively intact controls (n = 28) and patients with Alzheimer’s dementia (AD) (n = 24), a disease that has been cognitively associated with CTE. [F-18]FDDNP PET imaging results in the retired players suggested the presence of neuropathological patterns consistent with models of concussion wherein brainstem white matter tracts undergo early axonal damage and cumulative axonal injuries along subcortical, limbic, and cortical brain circuitries supporting mood, emotions, and behavior. This deposition pattern is distinctively different from the progressive pattern of neuropathology [paired helical filament (PHF)-tau and amyloid-β] in AD, which typically begins in the medial temporal lobe progressing along the cortical default mode network, with no or minimal involvement of subcortical structures. This particular [F-18]FDDNP PET imaging pattern in cases of suspected CTE also is primarily consistent with PHF-tau distribution observed at autopsy in subjects with a history of mild TBI and autopsy-confirmed diagnosis of CTE.The consensus statement on concussions from the Fourth International Conference on Concussion in Sports (Zurich 2012) (1) defines acute mild traumatic brain injury (mTBI) or cerebral concussion as a brain injury with a complex pathophysiological process induced by biomechanical forces. Cerebral concussion causes white matter axonal injury due to axonal shearing and stretching (2), typically resulting in the rapid onset of short-lived impairment of neurological function that resolves spontaneously and largely reflects a functional disturbance rather than a structural injury. As such, no abnormality is seen on standard structural neuroimaging determinations (1).A number of early literature reports described a neurodegenerative disease associated with a history of repetitive TBI in retired professional boxers (3, 4), with a prevalence rate of up to 47% among retired professional boxers aged 50 y and older who boxed for more than 10 y (5). Initially named “punch drunk syndrome” (3) and dementia pugilistica (4), this syndrome is now known as chronic traumatic encephalopathy (CTE) in the current literature (6, 7).Compelling autopsy evidence (6–8) and neurobehavioral determinations (9) of retired professional American football athletes indicate that a subgroup develops neurodegenerative and clinical changes typical of CTE, a progressive syndrome distinctively different from Alzheimer’s disease (AD), which is the most common form of dementia in the elderly (10). The connection between multiple concussions and subconcussive head impacts (2) and CTE is compelling, because history of repetitive concussions is the strongest risk factor for development of CTE in numerous contact sports (e.g., American football, rugby, boxing, ice hockey, soccer, and professional wrestling), in war veterans with a history of blast or blunt force TBI, and in conditions where trauma to the head occurs for various reasons (e.g., falls during seizures, head-banging in autistic children, motor vehicle and domestic accidents, domestic violence and abuse) (6, 8, 11–14). As with most neurodegenerative diseases, clinical diagnosis remains elusive due to the lack of specificity of CTE clinical symptomatology criteria, and histopathological examination of brain at autopsy is the most definitive diagnostic modality (6, 8, 11).The novel imaging approaches leading to the in vivo characterization of CTE brain neuropathology premortem (e.g., PET) are complementary to structural imaging modalities [e.g., diffusion tensor imaging MRI (DTI MRI)] and offer a specific and sensitive strategy to facilitate diagnosis of CTE. Neuronal and glial fibrillar hyperphosphorylated microtubule-associated protein tau deposits composed of paired helical filament (PHF)-tau are the primary brain proteinopathy of CTE based on autopsy determinations, and their 3R/4R tau isoform ratio is similar to that of AD (11). Their topographically predictable pattern of distribution was used as a basis for a severity staging system of CTE neuropathology (7), ranging from mild (neuropathology stages I and II) to advanced (neuropathology stages III and IV) (7) (Tables S1 and S2). In addition, more than 80% of analyzed pathologically confirmed CTE cases also show transactive response (TAR) DNA-binding protein of ∼43 kDa (TDP-43) either as inclusions in sparse neurites in cortex, medial temporal lobe structures, and brainstem in CTE neuropathology stages I–III, as widespread neuronal and glial inclusions in severe CTE cases (neuropathology stage IV), or in CTE cases with motor neuron disease (7, 15) (Tables S1 and S2). CTE cases also can exhibit the presence of other fibrillar protein aggregates. McKee et al. (7) and Omalu et al. (8) reported that in autopsy determinations, less than half of all CTE cases and less than one third of “pure” CTE cases show amyloid-β (Aβ) deposits, predominantly as scattered cortical diffuse plaques in low density (Tables S1 and S2). Of note is that subjects with Aβ deposits were significantly older than those without. Moreover, their neuropathology was more severe than that in cases without Aβ deposits and was often combined with α-synuclein deposits (7). As an example, as reported by McKee et al. (7), of 30 CTE cases with at least some cortical Aβ deposits (of 68 confirmed CTE cases), 29 brains were from subjects who died in their seventh decade of life and one from a subject who died in his sixth decade.Subsequent to our preliminary report (16), in this work we use [F-18]FDDNP, an imaging agent for fibrillar insoluble protein aggregates (16–20), and PET imaging with the aim of establishing (i) topographic brain localization of [F-18]FDDNP PET signals indicative of fibrillar neuroaggregates in retired professional American football players with suspected CTE (mTBI group) vs. controls (CTRL); (ii) determination of [F-18]FDDNP PET signal patterns in the mTBI group; (iii) presence of [F-18]FDDNP PET signal as a measure of neuropathology in the brain areas involved in mood disorders related neurocircuits; (iv) correlation of [F-18]FDDNP PET results with neuropathology distributions in confirmed CTE cases; (v) differential patterns of [F-18]FDDNP PET signals, and thus deposition of fibrillar neuroaggregates, in the mTBI group with respect to the AD group; and (vi) preliminary demonstration of differences in [F-18]FDDNP PET signal patterns in mTBI cases with different etiology, i.e., contact-sport–related mTBI in retired professional American football players vs. blast-induced mTBI in war veterans. We further intended to demonstrate that tau (vs. Aβ) specificity of high affinity PET molecular imaging probes may not be a necessary requirement when used in CTE subjects with primary proteinopathy in the form of PHF-tau (8): PET imaging probes potentially sensitive to TDP-43 aggregates and Aβ deposits, which are present in higher densities almost exclusively in older CTE cases with more advanced neuropathology (e.g., stage IV), could better define disease progression based on quantification of differences in regional loads of combined neuropathologies because additional neuropathologies appear in predictable topographical and temporal patterns.     

Previous mild traumatic brain injury and postural-control dynamics

Context:

Postural control and cognitive function are adversely affected by acute mild traumatic brain injury (mTBI). Whether postural-control deficits persist beyond the acute stage in individuals with a history of mTBI is unclear.

Objective:

To determine if postural-control deficits persist in individuals with a history of mTBI.

Design:

Retrospective cross-sectional study.

Setting:

University research laboratory.

Patients or Other Participants:

As part of an ongoing investigation examining cognitive and motor deficits associated with mTBI, 224 individuals participated in the study. Of these, 62 participants self-reported at least 1 previous physician-diagnosed mTBI.

Intervention(s):

Postural control was assessed using the NeuroCom Sensory Organization Test (SOT) postural-assessment battery.

Main Outcome Measure(s):

The SOT postural assessment yields 4 indices of postural control: a composite balance score, a visual ratio score, a somatosensory score, and a vestibular score. Postural dynamics were also examined by calculating approximate entropy of center-of-pressure excursions in the anteroposterior and mediolateral axis for each test condition.

Results:

Minimal differences in the SOT indices were noted among individuals with and without a history of previous mTBI (P > .05). In the group with a history of mTBI, anteroposterior postural irregularity decreased as postural difficulty increased. In contrast, the group without a history of mTBI displayed increased postural irregularity in the mediolateral direction.

Conclusions:

Individuals with a history of mTBI exhibited altered postural dynamics compared with individuals without a history of mTBI. These findings support the notion that changes in cerebral functioning that affect postural control may persist long after acute injury resolution.     

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

Context:

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

Objective:

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

Design:

Case series with repeated measures.

Setting:

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

Patients or Other Participants:

102 National Collegiate Athletic Association Division I athletes.

Interventions :

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

Main Outcome Measure(s):

Data were collected at 2 time points, 1 season apart, during preparticipation physical examinations. Outcomes were mean simple RT_clin and RT_comp.

Results:

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

Conclusions:

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

Retest Reliability of Force-Time Variables of Neck Muscles Under Isometric Conditions

Context:

Proper conditioning of the neck muscles may play a role in reducing the risk of neck injury and, possibly, concussions in contact sports. However, the ability to reliably measure the force-time–based variables that might be relevant for this purpose has not been addressed.

Objective:

To assess the between-days reliability of discrete force-time–based variables of neck muscles during maximal voluntary isometric contractions in 5 directions.

Design:

Cohort study.

Setting:

University research center.

Patients or Other Participants:

Twenty-six highly physically active men (age  =  21.6 ± 2.1 years, height  =  1.85 ± 0.09 m, mass  =  81.6 ± 9.9 kg, head circumference  =  0.58 ± 0.01 m, neck circumference  =  0.39 ± 0.02 m).

Intervention(s):

We used a custom-built testing apparatus to measure maximal voluntary isometric contractions of the neck muscles in 5 directions (extension, flexion, protraction, left lateral bending, and right lateral bending) on 2 separate occasions separated by 7 to 8 days.

Main Outcome Measure(s):

Variables measured were peak force (PF), rate of force development (RFD), and time to 50% of PF (T₅₀PF). Reliability indices calculated for each variable comprised the difference in scores between the testing sessions, with corresponding 95% confidence intervals, the coefficient of variation of the typical error of measurement (CV_TE), and intraclass correlation coefficients (ICC [3,3]).

Results:

No evidence of systematic bias was detected for the dependent measures across any movement direction; retest differences in measurements were between 1.8% and 2.7%, with corresponding 95% confidence interval ranges of less than 10% and overlapping zero. The CV_TE was lowest for PF (range, 2.4%–6.3%) across all testing directions, followed by RFD (range, 4.8%–9.0%) and T₅₀PF (range, 7.1%–9.3%). The ICC score range for all dependent measures was 0.90 to 0.99.

Conclusions:

Discrete variables representative of the force-generating capacity of neck muscles under isometric conditions can be measured with an acceptable degree of reliability. This finding has possible applications for investigating the role of neck muscle strength-training programs in reducing the risk of injuries in sport settings.     

Symptoms after sport-related concussions alter gestural functions

ObjectivesSymptoms after sport-related concussions (SRC) are common. Because post-concussion symptoms are often not clearly visible, speech-accompanying gestures may help clinicians to gain additional information about the patient’s history and symptoms during medical consultation. We hypothesized that athletes with SRC and who suffered from persisting symptoms would display more gestures during concussion assessment protocols when compared to non-concussed athletes because of the athletes’ previous motor-sensory experiences made during the concussive event.DesignA retrospective cross-sectional study.MethodsThree matched groups of 40 (active) athletes were investigated in the context of concussion assessment (/and baseline) protocols: 14 symptomatic and 14 asymptomatic athletes with a SRC, and 12 non-concussed athletes. Certified raters using a standard analysis system for nonverbal behaviour analysed videotaped hand movements and gestures during a standardized concussion assessment protocol.ResultsSymptomatic athletes spent significantly more time with in space hand movements, i.e., movements that act in the body-external free space without touching anything and specifically, motion quality presentation gestures than non-concussed athletes.ConclusionsIncreased in space movements, which are functionally gestures, and specifically, motion quality presentation gestures in symptomatic athletes indicate that the more vivid sensory motor experience of the head trauma is reflected in more gestural expressions. Thus, hand movements and gestures differentiate athletes who suffer from post-concussion symptoms from non-concussed athletes indicating the athletes’ motor-sensory experiences of the event and its aftereffects. The present study highlights the fact that gestures can be employed as behavioural markers of symptoms after sport-related concussions.     

Generalizability Theory Analysis of Balance Error Scoring System Reliability in Healthy Young Adults

Context:

An assessment of postural control is commonly included in the clinical concussion evaluation. Previous investigators have demonstrated learning effects that may mask concussion-induced balance decrements.

Objective:

To establish the test-retest reliability of the Balance Error Scoring System (BESS) and to provide recommendations that account for known learning effects.

Design:

Test-retest generalizability study.

Setting:

Balance research laboratory.

Patients or Other Participants:

Young adults (n  =  48) free from injuries and illnesses known to affect balance.

Intervention(s):

Each participant completed 5 BESS trials on each of the assessment dates, which were separated by 50 days.

Main Outcome Measure(s):

Total score of the BESS was used in a generalizability theory analysis to estimate the overall reliability of the BESS and that of each facet. A decision study was completed to estimate the number of days and trials needed to establish clinical reliability.

Results:

The overall reliability of the BESS was G  =  0.64. The test-retest reliability was improved when male (0.92) and female (0.91) participants were examined independently. Clinically acceptable reliability (greater than 0.80) was established when 3 BESS trials were administered in a single day or 2 trials were administered at different time points.

Conclusions:

Learning effects have been noted in individuals with no previous exposure to the BESS. Our findings indicate that clinicians should consider interpreting the mean score from 3 BESS administrations on a given occasion for both normative data comparison and pretest and posttest design. The multiple assessment technique yields clinically reliable scores and provides the sports medicine practitioner with accurate data for clinical decision making.     

多重脑震荡大鼠脑干中缝核团内5-羟色胺免疫阳性表达变化的研究

为了探讨多重脑震荡(multiple cerebral concussion,MCC)后大鼠中缝核团内5-羟色胺(5-HT)能神经元的变化规律,本实验采用自制单摆式机械打击装置复制MCC大鼠模型,研究伤后大鼠脑干中缝核团内5-HT及5-HT合成过程中的限速酶-色胺酸羟化酶(TPH)的表达。将56只大鼠随机分为7组:对照组、伤后1、2、4、8、16和24d组(n=8)。用免疫组织化学染色技术及图像分析法定量分析伤后大鼠脑干中缝核团内5-HT和TPH的表达变化。结果显示:(1)TPH免疫反应阳性产物在中缝背核、正中中缝核的表达在伤后2d时达到高峰,与正常对照组相比有显著性差异(P<0.05);中缝大核和中缝苍白核分别以伤后1d组和4d组阳性反应最强;(2)5-HT免疫反应阳性产物在中缝背核、正中中缝核的表达也在伤后2d时达到高峰,16、24d组基本恢复至正常水平;而中缝大核和中缝苍白核内5-HT的免疫反应性在各损伤组与正常对照组之间均无显著性差异(P>0.05)。以上结果表明,多重脑震荡后中缝核团内TPH和5-HT的表达增高,这为研究5-HT对MCC后认知障碍的影响提供了形态学依据。