Performance After Concussion in National Hockey League Players

ContextConcussions in ice hockey players are an interesting area of study due to the fast-paced and high-impact nature of the sport. Recently, researchers have focused on player performance after return from concussion to evaluate subclinical deficits that were previously missed.ObjectiveTo examine National Hockey League (NHL) player performance from 2013 to 2019 and compare performance before a concussion with performance immediately after recovering to assess the current NHL return-to-play protocol.DesignCross-sectional study.SettingThe NHL Injury Viz and sports reporting websites.Patients or Other ParticipantsPlayers in the NHL who sustained concussions from 2013 to 2019.Main Outcome Measure(s)Goals, assists, points, plus-minus, time on ice (TOI), and hits.ResultsWhen goals, assists, points, plus-minus, TOI, and hits were examined, only TOI was different after the players returned from injury, and this TOI difference was not substantively important.ConclusionsAfter concussion, NHL player performance did not change.     

Network Analysis of Sport-Related Concussion Research During the Past Decade (2010–2019)

ContextResearch into sport-related concussion (SRC) has grown substantially over the past decade, yet no authors to date have synthesized developments over this critical time period.ObjectiveTo apply a network-analysis approach in evaluating trends in the SRC literature using a comprehensive search of original, peer-reviewed research articles involving human participants published between January 1, 2010, and December 15, 2019.DesignNarrative review.Main Outcome Measure(s)Bibliometric maps were derived from a comprehensive search of all published, peer-reviewed SRC articles in the Web of Science database. A clustering algorithm was used to evaluate associations among journals, organizations or institutions, authors, and key words. The online search yielded 6130 articles, 528 journals, 7598 authors, 1966 organizations, and 3293 key words.ResultsThe analysis supported 5 thematic clusters of journals: (1) biomechanics/sports medicine (n = 15), (2) pediatrics/rehabilitation (n = 15), (3) neurotrauma/neurology/neurosurgery (n = 11), (4) general sports medicine (n = 11), and (5) neuropsychology (n = 7). The analysis identified 4 organizational clusters of hub institutions: (1) University of North Carolina (n = 19), (2) University of Toronto (n = 19), (3) University of Michigan (n = 11), and (4) University of Pittsburgh (n = 10). Network analysis revealed 8 clusters for SRC key words, each with a central topic area: (1) epidemiology (n = 14), (2) rehabilitation (n = 12), (3) biomechanics (n = 11), (4) imaging (n = 10), (5) assessment (n = 9), (6) mental health/chronic traumatic encephalopathy (n = 9), (7) neurocognition (n = 8), and (8) symptoms/impairments (n = 5).ConclusionsThe findings suggest that during the past decade, SRC research has (1) been published primarily in sports medicine, pediatric, and neuro-focused journals, (2) involved a select group of researchers from several key institutions, and (3) concentrated on new topical areas, including treatment or rehabilitation and mental health.     

Concussion history and postconcussion neurocognitive performance and symptoms in collegiate athletes

CONTEXT: Athletes are at an inherent risk for sustaining concussions. Research examining the long-term consequences of sport-related concussion has been inconsistent in demonstrating lingering neurocognitive decrements that may be associated with a previous history of concussion. OBJECTIVE: To determine the relationship between concussion history and postconcussion neurocognitive performance and symptoms in collegiate athletes. DESIGN: Repeated-measures design. SETTING: Multi-center analysis of collegiate athletes. PATIENTS OR OTHER PARTICIPANTS: Fifty-seven concussed collegiate athletes (36 without concussion history, 21 with a history of 2 or more concussions). INTERVENTION(S): All subjects were administered an Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) neurocognitive test battery, which measures verbal memory, visual memory, reaction time, and visual processing speed and 22 concussion symptoms. MAIN OUTCOME MEASURE(S): Subjects who sustained a concussion were administered 2 follow-up tests at days 1 and 5 postinjury. Independent variables were history of concussion (no history of concussion, 2 or more concussions) and time (baseline, day 1 postconcussion, or day 5 postconcussion). RESULTS: A within-subjects effect (time) on ImPACT performance (P < .001), a between-subjects multivariate effect of group (P < .001), and a group-by-time interaction (P = .034) were noted. Athletes with a concussion history performed significantly worse on verbal memory (P = .01) and reaction time (P = .023) at day 5 postconcussion compared with athletes who did not report a previous concussion. No significant group differences were seen at day 5 postinjury on visual memory (P = .167), processing speed (P = .179), or total concussion symptoms (P = .87). CONCLUSIONS: Concussed collegiate athletes with a history of 2 or more concussions took longer to recover verbal memory and reaction time than athletes without a history of concussion.     

Symptom Provocation During Aerobic and Dynamic Supervised Exercise Challenges in Adolescents With Sport-Related Concussion

ContextSupervised exercise challenges (SECs) have been shown to be safe and beneficial in the early symptomatic period after concussion. Thus far, most in-clinic SECs studied have included a form of basic aerobic exercise only. An SEC that also includes dynamic forms of exercise mimics all steps of a standard return-to-play progression and may enhance the detection of concussion symptoms to guide in-clinic management decisions.ObjectiveTo determine whether an SEC that includes a dynamic SEC (DSEC) uncovered symptoms that would not have been identified by an SEC involving an aerobic SEC (ASEC) alone in adolescent patients with sport-related concussion.DesignRetrospective case series.SettingMultidisciplinary sport concussion clinic at a tertiary care center.Patients or Other ParticipantsA total of 65 adolescent athletes (mean age = 14.9 ± 2.0 years, 72.3% males) who underwent an in-clinic SEC within 30 days of concussion.Main Outcome Measure(s)Presence of pre-exercise symptoms and symptom provocation during the SEC were recorded, with exercise-provoked symptoms categorized as occurring during ASEC or DSEC.ResultsOf the total patient sample, 69.2% (n = 45/65) experienced symptom provocation at some point during the SEC. Symptoms were provoked in 20 patients during the ASEC, whereas 25 completed the ASEC without symptom provocation before becoming symptomatic during the subsequent DSEC and 20 completed the SEC without any symptom provocation. Of the 65 patients in the total sample, 46 were asymptomatic immediately before the SEC. Of these previously asymptomatic patients, 23.9% (n = 11/46) experienced symptom provocation during the ASEC, and an additional 37.0% (n = 17/46) remained asymptomatic during the ASEC but then developed symptoms during the DSEC.ConclusionsThe ASEC alone may not detect symptom provocation in a significant proportion of concussion patients who otherwise would develop symptoms during a DSEC.     

Factors Associated With Energy Expenditure and Energy Balance in Acute Sport-Related Concussion

ContextSport-related concussion (SRC) is characterized by a pathologic neurometabolic cascade that results in an increased intracranial energy demand and a decreased energy supply. Little is known about the whole-body energy-related effects of SRC.ObjectiveTo examine factors associated with whole-body resting metabolic rate (RMR), total energy expenditure (TEE), energy consumption (EC), and energy balance (EBal) in student-athletes acutely after SRC and healthy matched control individuals.DesignCase-control study.SettingUniversity research laboratory.Patients or Other ParticipantsStudent-athletes diagnosed with SRC (n = 28, 50% female, age = 18.4 ± 1.8 years, body mass index [BMI] = 24.1 ± 4.1 kg/m²) assessed ≤72 hours postinjury and a matched control group (n = 28, 50% female, age = 19.4 ± 2.9 years, BMI = 24.7 ± 4.78 kg/m²).Main Outcome Measure(s)Resting metabolic rate was measured via indirect calorimetry. Participants reported their physical activity and dietary intake for 3 days, which we used to estimate TEE and EC, respectively, and to calculate EBal (EC:TEE ratio). Resting metabolic rate, TEE, and EC were normalized to body mass. Group and group-by-sex comparisons were conducted for RMR·kg⁻¹, TEE·kg⁻¹, EC·kg⁻¹, and EBal using independent t tests with the a priori α = .05. Associations of age, sex, concussion history, BMI, and symptom burden with RMR·kg⁻¹ and EBal were explored with linear regression models.ResultsTotal energy expenditure·kg⁻¹ was lower (P < .01; mean difference ± SD = −5.31 ± 1.41 kcal·kg⁻¹) and EBal was higher (P < .01; 0.28 ± 0.10) in SRC participants than in control participants. Both sexes with SRC had lower TEE·kg⁻¹ than did the control participants (P values ≤ .04); females with SRC had higher EBal than controls (P = .01), but male groups did not differ. Higher RMR·kg⁻¹ was associated with history of concussion (adjusted R² = .10, β = 0.65). Younger age (β = −0.35), fewer concussions (β = −0.35), lower BMI (β = −0.32), greater symptom duration (β = 1.50), and lower symptom severity (β = −1.59) were associated with higher EBal (adjusted R² = .54).ConclusionsTotal energy expenditure·kg⁻¹ and EBal appeared to be affected by acute SRC, despite no differences in RMR·kg⁻¹. Sex, concussion history, BMI, and symptom burden were associated with acute energy-related outcomes.     

Association Between Previous Concussion Education and Concussion Care-Seeking Outcomes Among National Collegiate Athletic Association Division I Student-Athletes

ContextLimited data exist concerning differences in concussion-education exposure and how education exposures relate to care seeking and symptom disclosure, specifically by National Collegiate Athletic Association Division I student-athletes.ObjectiveTo investigate demographic characteristics associated with concussion-education exposure and examine whether overall education exposure (yes versus no) and education-source exposure number (multiple sources versus a single source) affect concussion care-seeking and disclosure factors in Division I student-athletes.DesignCross-sectional study.SettingClassroom or online survey.Patients or Other ParticipantsDivision I student-athletes (n = 341).Main Outcome Measure(s)Frequencies and proportions were computed for sex, race, school year, sport, and concussion history across concussion-education groups. Prevalence ratios (PRs) and 95% CIs were calculated to quantify the associations between student-athlete characteristics and (1) overall concussion-education exposure and (2) source-exposure number. Separate multivariable linear regression models estimated adjusted mean differences (MDs) and 95% CIs, which allowed us to assess differences in concussion knowledge, attitudes, and perceived social norms relative to concussion-education exposure and exposure to multiple sources. Separate multivariable binomial regression models were performed to estimate adjusted PRs and 95% CIs in order to evaluate associations of intention, perceived control, and care-seeking or disclosure behaviors and overall concussion-education exposure and exposure to multiple sources. All models controlled for sex, sport, and concussion history.ResultsOverall, 276 (80.9%) participants reported previous concussion education, with 179 (64.9%) being exposed to multiple sources. Student-athletes who participated in a contact sport (adjusted PR = 1.24; 95% CI = 1.06, 1.44) and those who had a concussion history (adjusted PR = 1.19; 95% CI = 1.09, 1.31) had higher prevalences of concussion-education exposure. Females had a lower prevalence of reporting multiple sources (adjusted PR = 0.82; 95% CI = 0.68, 0.99). Overall concussion-education exposure was significantly associated with more favorable perceived social norms surrounding concussion care seeking (adjusted MD = 1.37; 95% CI = 0.13, 2.61).ConclusionsThese findings highlighted the potential differences in overall concussion-education exposure and provide clinicians with information on groups who may benefit from additional targeted education.     

Helmet Fit Assessment and Concussion Risk in Youth Ice Hockey Players: A Nested Case-Control Study

ContextInjury surveillance has shown that concussions are the most common injury in youth ice hockey. Research examining the criteria for ensuring the correct fit of protective equipment and its potential relationship with concussion risk is very limited.ObjectiveTo evaluate the association between helmet fit and the odds of experiencing a concussion among youth ice hockey players.DesignNested case-control within a cohort study.SettingCalgary, Alberta, Canada.Patients or Other ParticipantsData were collected for 72 concussed, 41 nonconcussion-injured, and 62 uninjured ice hockey players aged 11 to 18 years.Main Outcome Measure(s)Helmet-fit assessments were conducted across players and encompassed helmet specifications, condition, certification, and criteria measuring helmet fit. Using a validated injury-surveillance system, we identified participants as players with suspected concussions or physician-diagnosed concussions or both. One control group comprised players who sustained nonconcussion injuries, and a second control group comprised uninjured players. Helmet-fit criteria (maximum score = 16) were assessed for the concussed players and compared with each of the 2 control groups. The primary outcome was dichotomous (>1 helmet-fit criteria missing versus 0 or 1 criterion missing). Logistic and conditional logistic regression were used to investigate the effect of helmet fit on the odds of concussion.ResultsThe primary analysis (54 pairs matched for age, sex, and level of play) suggested that inadequate helmet fit (>1 criterion missing) resulted in greater odds of sustaining a concussion when comparing concussed and uninjured players (odds ratio [OR] = 2.67 [95% CI = 1.04, 6.81], P = .040). However, a secondary unmatched analysis involving all participants indicated no significant association between helmet fit and the odds of sustaining a concussion when we compared concussed players with nonconcussion-injured players (OR = 0.98 [0.43, 2.24], P = .961) or uninjured players (OR = 1.66 [0.90, 3.05], P = .103).ConclusionsInadequate helmet fit may affect the odds of sustaining a concussion in youth ice hockey players. Future investigators should continue to evaluate this relationship in larger samples to inform helmet-fit recommendations.     

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.     

Interpreting Clinical Reaction Time Change and Recovery After Concussion: A Baseline Versus Norm-Based Cutoff Score Comparison

ContextPreseason testing can be time intensive and cost prohibitive. Therefore, using normative data for postconcussion interpretation in lieu of preseason testing is desirable.ObjectiveTo establish the recovery trajectory for clinical reaction time (RT_clin) and assess the usefulness of changes from baseline (comparison of postconcussion scores with individual baseline scores) and norm-based cutoff scores (comparison of postconcussion scores with a normative mean) for identifying impairments postconcussion.DesignCase-control study.SettingMultisite clinical setting.Patients or Other ParticipantsAn overlapping sample of 99 participants (age = 19.0 ± 1.1 years) evaluated within 6 hours postconcussion, 176 participants (age = 18.9 ± 1.1 years) evaluated at 24 to 48 hours postconcussion, and 214 participants (age = 18.9 ± 1.1 years) evaluated once they were cleared to begin a return-to-play progression were included. Participants with concussion were compared with 942 control participants (age = 19.0 ± 1.0 years) who did not sustain a concussion during the study period but completed preseason baseline testing at 2 points separated by 1 year (years 1 and 2).Main Outcome Measure(s)At each time point, follow-up RT_clin (ie, postconcussion or year 2) was compared with the individual year 1 preseason baseline RT_clin and normative baseline data (ie, sex and sport specific). Receiver operating characteristic curves were calculated to compare the sensitivity and specificity of RT_clin change from baseline and norm-based cutoff scores.ResultsClinical reaction time performance declined within 6 hours (18 milliseconds, 9.2% slower than baseline). The decline persisted at 24 to 48 hours (15 milliseconds, 7.6% slower than baseline), but performance recovered by the time of return-to-play initiation. Within 6 hours, a change from baseline of 16 milliseconds maximized combined sensitivity (52%) and specificity (79%, area under the curve [AUC] = 0.702), whereas a norm-based cutoff score of 19 milliseconds maximized combined sensitivity (46%) and specificity (86%, AUC = 0.700). At 24 to 48 hours, a change from baseline of 2 milliseconds maximized combined sensitivity (64%) and specificity (61%, AUC = 0.666), whereas a norm-based cutoff score of 0 milliseconds maximized combined sensitivity (63%) and specificity (62%, AUC = 0.647).ConclusionsNorm-based cutoff scores can be used for interpreting RT_clin scores postconcussion in collegiate athletes when individual baseline data are not available, although low sensitivity and specificity limit the use of RT_clin as a stand-alone test.     

Current Sport-Related Concussion Teaching and Clinical Practices of Sports Medicine Professionals

Context:

Various consensus and position statements recommend a multifaceted approach when diagnosing a possible concussion. The effectiveness of these materials depends largely on their content being disseminated to educators and to those in the clinical setting.

Objective:

To identify the concussion management methods and guidelines currently taught in the athletic training classroom and clinical settings and to track the dissemination of the Vienna guidelines throughout the educational curriculum.

Design:

A 17-question Internet survey.

Setting:

A Web link was e-mailed to the program directors and certified athletic trainers holding educational positions in athletic training at 300 accredited programs in the United States.

Patients or Other Participants:

513 program directors and athletic trainers.

Main Outcome Measure(s):

Survey questions addressed education level, years of certification, employment setting, concussion assessment and return-to-play guidelines used in the clinical setting and the classroom, and clinical and teaching preferences for existing position statements and concussion grading systems. The Vienna guidelines'' “simple” and “complex” definitions of concussions were provided with the return-to-play stepwise approach.

Results:

The National Athletic Trainers'' Association position statement was the most widely used method of assessing, managing (61%), and making return-to-play decisions (47%) among participants. More than half of participants (66%) had never heard of the Vienna guidelines. After reading the Vienna guidelines'' definitions and return-to-play criteria, nearly three-fourths of participants agreed with them. In addition, 68% said that they would use them, and 84% reported that they would teach them to students.

Conclusions:

The majority of program directors and certified athletic trainers used a multidimensional approach to assess and manage a concussion. The National Athletic Trainers'' Association position statement and Vienna guidelines were underused in both the classroom and clinical settings.     

长时程亚低温治疗对重度颅脑损伤患者脑损伤标志物及氧化应激指标的影响

目的:探讨长时程亚低温治疗对重度颅脑损伤患者脑损伤标志物及氧化应激指标的影响。方法:62例重度颅脑损伤患者根据治疗方式不同将其分为短时程（2 d）亚低温治疗组（对照组, n=30）和长时程（5 d）亚低温治疗组（观察组, n=32）,治疗后第6天时比较两组患者凝血功能指标、脑损伤标志物、氧化应激指标、并发症发生情况,随访期间观察患者昏迷时间及30 d致残率与30 d病死率。结果:治疗后第6天时,观察组血清凝血酶原时间、凝血酶时间、活化部分凝血酶原时间水平高于对照组（P<0.05）,观察组血清D-二聚体水平低于对照组（P<0.05）。治疗后第6天时,观察组患者血清髓鞘碱蛋白、神经元特异性烯醇化酶、S100蛋白、丙二醛、超氧化物歧化酶水平均低于对照组（P<0.05）。两组患者颅内血肿、胃肠动力减弱、泌尿系感染、肺部感染、应激性溃疡发生率无统计学差异（P>0.05）。观察组患者昏迷时间较对照组缩短（P<0.05）;观察组患者30 d致残率及30 d病死率均低于对照组,但两组间差异无统计学意义（P>0.05）。结论:长时程亚低温治疗有利于改善重度颅脑损伤患者凝血功能,降低脑损伤标志物水平及氧化应激损伤,缩短昏迷时间,且不增加并发症发生风险。     

Persistent problems 1 year after mild traumatic brain injury: a longitudinal population study in New Zealand

Background

Mild traumatic brain injury (mTBI) is a common problem in general practice settings, yet previous research does not take into account those who do not attend hospital after injury. This is important as there is evidence that effects may be far from mild.

Aim

To determine whether people sustain any persistent effects 1 year after mTBI, and to identify the predictors of health outcomes.

Design and setting

A community-based, longitudinal population study of an mTBI incidence cohort (n = 341) from a mixed urban and rural region (Hamilton and Waikato Districts) of the North Island of New Zealand (NZ).

Method

Adults (>16 years) completed assessments of cognitive functioning, global functioning, post-concussion symptoms, mood, and quality of life over the year after injury.

Results

Nearly half of participants (47.9%) reported experiencing four or more post-concussion symptoms 1 year post-injury. Additionally, 10.9% of participants revealed very low cognitive functioning. Levels of anxiety, depression, or reduced quality of life were comparable with the general population. Having at least one comorbidity, history of brain injury, living alone, non-white ethnic group, alcohol and medication use, and being female were significant predictors of poorer outcomes at 12 months.

Conclusion

Although some people make a spontaneous recovery after mTBI, nearly half continue to experience persistent symptoms linked to their injury. Monitoring of recovery from mTBI may be needed and interventions provided for those experiencing persistent difficulties. Demographic factors and medical history should be taken into account in treatment planning.     

脑微损伤的影像学进展

脑微损伤是创伤性脑损伤最常见的类型,然而,其潜在的神经生理机制尚未完全阐明,影响患者的早期诊断、治疗及预后评估。近年来,多项磁共振（MRI）新技术不断地涌现并用于评估脑微损伤,如功能磁共振、灌注MRI、弥散张量成像、定量易感性图谱、T2 mapping等。本研究综述了多模态MRI在脑微损伤中的应用,从不同的角度深入地了解脑微损伤的神经病理机制,有助于提高临床医生对脑微损伤的诊断和治疗。     

Assessment of Postural Stability During an Upper Extremity Rapid,Bimanual Motor Task After Sport-Related Concussion

ContextSport-related concussion (SRC) often presents with multidimensional and subtle neurologic deficits that are difficult to detect with standard clinical tests. New assessment approaches that efficiently quantify deficits across multiple neurologic domains are needed.ObjectiveTo quantify impairments in postural movements during an assessment of rapid, bimanual motor ability in athletes within 10 days of experiencing an SRC and evaluate relationships between impairments in upper extremity and postural performance.DesignCohort study.SettingSports medicine clinic.Patients or Other ParticipantsInitial baseline assessments were completed for 711 athletes. Seventy-five athletes (age = 15.8 ± 3.3 years at baseline) sustained SRCs and were reassessed within 10 days. Seventy-eight athletes (age = 15.5 ± 2.0 years) completed 2 assessments in a healthy state.Main Outcome Measure(s)Athletes stood on force plates and performed a rapid, bimanual motor task, termed the object-hit task, delivered using a Kinesiological Instrument for Normal and Altered Reaching Movements endpoint robot. Measures of postural stability that quantified center-of-pressure movements and measures of upper extremity performance were used to characterize task performance.ResultsPerformance changes across assessments were converted to reliable change indices. We observed a difference in reliable change indices values between athletes with SRC and healthy control athletes on the combined postural measures (P = .01). Using measures to evaluate the change in postural movements from the early, easier portion of the task to the later, more difficult portion, we identified the highest levels of impairment (19%–25% of the sample impaired). We also noted a difference between individuals with concussion and healthy individuals on the combined upper extremity measures (P = .003), but these impairments were largely unrelated to those identified in the postural movements.ConclusionsMeasurement of postural movements during the object-hit task revealed impairments in postural stability that were not related to impairments in upper extremity performance. The findings demonstrated the benefits of using assessments that simultaneously evaluate multiple domains of neurologic function (eg, upper extremity and postural control) after SRC.     

Pilot Evaluation of a Novel Clinical Test of Reaction Time in National Collegiate Athletic Association Division I Football Players

Context:

Evidence suggests that concussion prolongs reaction time (RT). We have developed a simple, reliable clinical tool for measuring reaction time that may be of value in the assessment of concussion in athletes.

Objective:

To compare baseline values of clinical RT (RT_clin) obtained using the new clinical reaction time apparatus with computerized RT (RT_comp) obtained using a validated computerized neuropsychological test battery.

Design:

Cross-sectional study.

Setting:

Data were collected during a National Collegiate Athletic Association Division I collegiate football team''s preparticipation physical examination session.

Patients or Other Participants:

Ninety-four Division I collegiate football players.

Main Outcome Measure(s):

The RT_clin was measured using a 1.3-m 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 RT component of CogState Sport.

Results:

For the 68 athletes whose CogState Sport tests passed the program''s integrity check, RT_clin and RT_comp were correlated (r  =  0.445, P < .001). Overall, mean RT_clin was shorter and less variable than mean RT_comp (203 ± 20 milliseconds versus 268 ± 44 milliseconds; P < .001). When RT_clin and RT_comp were compared between those athletes with (n  =  68) and those without (n  =  26) valid CogState Sport test sessions, mean RT_clin was similar (202 ± 19 milliseconds versus 207 ± 23 milliseconds; P  =  .390), but mean RT_comp was different (258 ± 35 milliseconds versus 290 ± 55 milliseconds; P  =  .009).

Conclusions:

The RT_clin was positively correlated with RT_comp and yielded more consistent reaction time values during baseline testing. Given that RT_clin is easy to measure using simple, inexpensive equipment, further prospective study is warranted to determine its clinical utility in the assessment of concussion in athletes.     

脑梗塞患者心率变异性及其意义初探

以24小时全体心搏心率/R—R平均值标准差(SD)即时域法研究56例脑梗塞患者及41例健康对照者的心率变异性(HRV),并按脑梗塞侧别及病情严重性分为左、右侧及轻、中、重数个亚组进行研究。结果发现,脑梗塞组HRV显著低于对照组(P<0.001),右侧半球脑梗塞HRV显著低于左侧半球脑梗塞(P<0.01),轻、中、重不同严重程度脑梗塞HRV之间无显著差异。脑梗塞组有2例病人于半年内死于心源性猝死,其HRV均<50ms。本文对脑梗塞患者HRV意义进行了探讨。     

正常人短时心率变异性指标在长时序列中的分布特性及其年龄的影响

无创的心率变异性(HRV)检测所反映的自主神经状态可受生理、病理和心理等因素影响。提出研究短时HRV分析指标在长时序列中的分布特性,并探讨在正常人中随年龄可能发生的变化。将THEW中Normal子数据库中年龄大于18岁的Holter数据(n=177)分为5个年龄组(18≤y≤25, n=35; 25< y≤35, n=44; 35< y≤45, n=41; 45< y≤55, n=34; y >55, n=23)。利用5 min的滑动窗口、2.5 min的步长,计算每个滑动窗的RR间期均值(MRRI)、LF/HF和短时分形尺度指数(α₁),然后基于长时序列,分别计算MRRI和LF/HF,以及MRRI和α₁这两种配对的Spearman相关系数,并在各组内统计相关性良好人数的百分占比。然后,以具有正常作息时间和数据长度为筛选标准,从177名正常人中筛选出93名25<y≤65岁的受试数据,并以10岁为间隔分为4个年龄组,计算每人各个2 h时段中的各5 min滑动窗(2.5 min步长)的指标均值(EM_MRRI、EM_LF/HF和EM_α₁)。结果表明,具有良好相关性的人数百分占比在18≤y≤55的年龄段保持高水平(94%～100%),但在年龄大于55岁后急剧下降(MRRI vs LF/HF: 78.26%; MRRI vs α₁: 65.22%)。对于清晨最低EM_MRRI时段,其EM_MRRI、EM_LF/HF和EM_α₁在各年龄组均不存在显著差异(P>0.05)),但在其他时段这些参数则可能存在显著差异。随着可穿戴技术的发展,长时心率序列(RR间期序列)的可获得性大幅度提高,该研究结果对于拓展长时序列的HRV分析方法可提供新的思路。     

Clinical Features of Repetitive Traumatic Brain Injury and Chronic Traumatic Encephalopathy

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease characterized by a distinct pattern of hyperphosphorylated tau (p‐tau). Thought to be caused by repetitive concussive and subconcussive injuries, CTE is considered largely preventable. The majority of neuropathologically confirmed cases have occurred in professional contact sport athletes (eg, boxing, football). A recent post‐mortem case series has magnified concerns for the public's health following its identification in six high school level athletes. CTE is diagnosed with certainty only following a post‐mortem autopsy. Efforts to define the etiology and clinical progression during life are ongoing. The goal of this article is to characterize the clinical concepts associated with short‐ and long‐term effects of repetitive traumatic brain injury, with a special emphasis on new clinical diagnostic criteria for CTE. Utilizing these new diagnostic criteria, two cases of neuropathologically confirmed CTE, one in a professional football player and one in a professional boxer, are reported. Differences in cerebellar pathology in CTE confirmed cases in boxing and football are discussed.     

Diverse changes in microglia morphology and axonal pathology during the course of 1 year after mild traumatic brain injury in pigs

Over 2.8 million people experience mild traumatic brain injury (TBI) in the United States each year, which may lead to long‐term neurological dysfunction. The mechanical forces that are caused by TBI propagate through the brain to produce diffuse axonal injury (DAI) and trigger secondary neuroinflammatory cascades. The cascades may persist from acute to chronic time points after injury, altering the homeostasis of the brain. However, the relationship between the hallmark axonal pathology of diffuse TBI and potential changes in glial cell activation or morphology have not been established in a clinically relevant large animal model at chronic time points. In this study, we assessed the tissue from pigs subjected to rapid head rotation in the coronal plane to generate mild TBI. Neuropathological assessments for axonal pathology, microglial morphological changes, and astrocyte reactivity were conducted in specimens out to 1‐year post‐injury. We detected an increase in overall amyloid precursor protein pathology, as well as periventricular white matter and fimbria/fornix pathology after a single mild TBI. We did not detect the changes in corpus callosum integrity or astrocyte reactivity. However, detailed microglial skeletal analysis revealed changes in morphology, most notably increases in the number of microglial branches, junctions, and endpoints. These subtle changes were most evident in periventricular white matter and certain hippocampal subfields, and were observed out to 1‐year post‐injury in some cases. These ongoing morphological alterations suggest persistent change in neuroimmune homeostasis. Additional studies are needed to characterize the underlying molecular and neurophysiological alterations, as well as potential contributions to neurological deficits.