Core Concussion Study Flashcards
Leddy (2018)
Safety and Prognostic Utility of Provocative Exercise Testing in Acutely Concussed Adolescents
Objective:
To evaluate (1) systematic assessment of exercise tolerance in adolescents shortly after sport-related concussion (SRC) and (2) the prognostic utility of such assessment.
Design:
Prospective randomized controlled trial.
Setting:
University and community sports medicine centers.
Participants:
Adolescents with SRC (1–9 days from injury). Sixty-five were randomized and 54 completed the study (mean age 15 years, 4 days after injury).
Interventions:
Buffalo Concussion Treadmill Test (BCTT, n = 27) or not (controls, n = 27) on visit day #1. Heart rate threshold (HRt) at symptom exacerbation represented level of exercise tolerance. Participants reported symptoms daily for 14 days and then had follow-up BCTT (n = 54). Recovery was defined as returning to normal level of symptoms and exercise tolerance, verified by independent physician examination.
Main Outcome Measures:
Days to recovery and typical (≤21 days) versus prolonged recovery (>21 days). Mixed effects linear models and linear regression techniques examined symptom reports and time to recovery. Linear regression assessed the association of HRt with recovery time.
Results:
Days to recovery (P = 0.7060) and typical versus prolonged recovery (P = 0.1195) were not significantly different between groups. Symptom severity scores decreased in both groups over 14 days (P < 0.0001), were similar (P = 0.2984), and did not significantly increase the day after the BCTT (P = 0.1960). Lower HRt on visit day #1 was strongly associated with prolonged recovery time (P = 0.0032).
Conclusions:
Systematic evaluation of exercise tolerance using the BCTT within 1 week after SRC did not affect recovery. The degree of early exercise intolerance after SRC was important for prognosis. This has implications for school academic and team preparation.
Haider (2019)
The Buffalo Concussion Bike Test for Concussion Assessment in Adolescents
Background:
The Buffalo Concussion Treadmill Test (BCTT) is a graded exertion test for assessing exercise tolerance after concussion, but its utility is limited for certain populations.
Hypothesis:
We developed the Buffalo Concussion Bike Test (BCBT) and tested its comparability with the BCTT. We hypothesize that heart rate (HR) at symptom exacerbation on the BCBT will be equivalent to the BCTT.
Study Design:
Case-control study.
Methods:
Adolescents with acute concussion (AC) (n = 20; mean age, 15.9 ± 1.1 years; 60% male) presenting to a concussion clinic within 10 days of injury and age- and sex-matched healthy controls (n = 20; mean age, 15.9 ± 1.1 years; 60% male) performed the BCTT at first visit and returned within 3 days to perform the BCBT. Test duration, HR, symptom severity (measured using a visual analog scale), and exertion (measured using the Borg Rating of Perceived Exertion) were collected during each test.
Results:
Adolescents with AC who were exercise intolerant on the BCTT were also intolerant on the BCBT, with symptom exacerbation occurring at a mean 8.1 ± 2.8 minutes on the BCTT versus 14.6 ± 6.0 minutes on the BCBT (P < 0.01). Two 1-sided t tests showed that the HR at symptom exacerbation in AC patients (137 ± 28 bpm on BCTT vs 135 ± 25 bpm on BCBT; 95% CI, <0.01-0.03) and at voluntary exhaustion for controls (175 ± 13 bpm on BCTT vs 175 ± 13 bpm on BCBT; 95% CI, 0.03-0.03) on each test were statistically equivalent.
Conclusion:
The HR at symptom exacerbation on BCBT is equivalent to the BCTT for the assessment of exercise tolerance after concussion in adolescents.
Clinical Relevance:
The BCBT can be used in patients with limited mobility or for research interventions that require limited participant motion.
Webb (2018)
Oculomotor Executive Dysfunction during the Early and Later Stages of Sport-Related Concussion Recovery
Executive dysfunction represents the most persistent sequela of mild traumatic brain injury. It is, however, largely unclear whether a sport-related concussion similarly contributes to a persistent executive dysfunction even when an athlete has been cleared medically for return to play.
Here, individuals with a diagnosis of a sport-related concussion—and their age- and sex-matched controls—completed an oculomotor assessment during the acute and later stages of injury recovery. Prosaccades (i.e., saccade to a target) and executive-related antisaccades (i.e., saccade mirror-symmetrical to a target) were completed: (1) 2–6 days after a concussive event (initial assessment), and (2) 14–20 days after the initial oculomotor assessment when individuals were cleared for return to play (follow-up assessment).
At the initial assessment, the concussed group produced antisaccade reaction times (RT) that were 93 ms longer than the control group (p < 0.001), whereas prosaccade RTs did not differ between groups (p = 0.25). At the follow-up assessment, concussed and control groups produced comparable pro- and antisaccade RTs (ps >0.31); however, the former group exhibited a continued increase in directional errors (p < 0.05). That initial assessment antisaccades—but not prosaccades—differed between groups indicates that the acute recovery of a concussion is associated with a selective executive-related oculomotor deficit, and the continued increase in directional errors at the follow-up assessment suggests that such a deficit persists even when an athlete has been cleared medically for return to play.
The antisaccade task may therefore serve to assess subtle executive deficits and determine when an athlete may return to play safely.
Johnson (2015)
Functional neuroimaging of acute oculomotor deficits in concussed athletes
In the pursuit to better understand the neural underpinnings of oculomotor deficits following concussion we performed a battery of oculomotor tests while performing simultaneous functional magnetic resonance imaging (fMRI). Based on the increasing evidence that concussion can disrupt multiple brain functional networks, including the oculomotor control networks, a series of classic saccadic and smooth pursuit tasks were implemented.
Nine concussed athletes were tested within seven days of injury along with nine age and sex matched healthy normal volunteers. Both behavioral and fMRI data revealed differential results between the concussed and normal volunteer groups.
Concussed subjects displayed longer latency time in the saccadic tasks, worse position errors, and fewer numbers of self-paced saccades compared to normal volunteer subjects. Furthermore, the concussed group showed recruitment of additional brain regions and larger activation sites as evidenced by fMRI.
As a potential diagnostic and management tool for concussion, oculomotor testing shows promise, and here we try to understand the reasons for this disrupted performance with the aide of advanced neuroimaging tools.
Johnson (2015b)
Follow-up evaluation of oculomotor performance with fMRI in the subacute phase of concussion
Objective:
To expand on our previous study by performing a follow-up testing session in the subacute phase of injury for participants recently diagnosed with a concussion.
Methods:
A battery of oculomotor tests were administered to participants 30 days postconcussion while simultaneous fMRI was performed.
Results:
Three of the 7 oculomotor tasks (antisaccade, self-paced saccade, and memory-guided saccade) administered showed significant differences between the recently concussed group compared with normal volunteers. However, performance in these 3 tasks did show improvement from the acute phase of injury. The fMRI analysis revealed significant differences in brain activation patterns compared with normal volunteers, with the concussed group still demonstrating increased and larger areas of activation. Similar to the oculomotor performance, the fMRI analysis showed that at 30 days postinjury, the concussed group more closely mirrored that of the normal volunteer group compared with at 7 days following insult.
Conclusions:
Even at 30 days postinjury, and despite being clinically asymptomatic, advanced techniques are able to detect subtle lingering alterations in the concussed brain. Therefore, progressive neuroimaging techniques such as fMRI in conjunction with assessment of oculomotor performance may be beneficial in clinical management of concussion.
Howell (2013)
Effects of Concussion on Attention and Executive Function in Adolescents
Background
Head trauma in adolescents has been linked with deficits in attention and executive function that can compromise the performance of everyday tasks. Although previous research has examined this issue using computerized neuropsychological testing, little work has been done using laboratory-based measurements of attention and executive function in this population. A longitudinal analysis of recovery patterns of these measures among adolescents is central to understanding the effects of concussions across the age spectrum.
Purpose
This study prospectively and longitudinally examined laboratory-based measures of attention and executive function in concussed adolescents sequentially during a 2-month period after injury.
Methods
Two measures of attention and executive function, the Attentional Network Test and the Task-Switching Test, were administered to 20 concussed adolescents within 72 h postinjury as well as at 1 wk, 2 wk, 1 month, and 2 months postinjury. Twenty healthy, matched control subjects were similarly assessed at the same time intervals. Data were analyzed by two-way, mixed-effects ANOVA to determine the effect of group and time on the dependent variables.
Results
Compared with control subjects, the concussed group exhibited a significantly greater switch cost on the Task-Switching Test (P = 0.038, mean difference value = 38 ms) and a significantly greater reaction time for the Attentional Network Test conflict effect component (P = 0.015, mean difference value = 34 ms) for up to 2 months after injury.
Conclusions
Concussed adolescents have difficulty recovering executive function after injury and may require extended recuperation time before full recovery is achieved. Evaluations focusing on attention and executive function can be useful additions in the assessment and follow-up after head injury.
Leddy (2022)
Rest and exercise early after sport-related concussion: a systematic review and meta-analysis
Objective To synthesise the evidence regarding the risks and benefits of physical activity (PA), prescribed aerobic exercise treatment, rest, cognitive activity and sleep during the first 14 days after sport-related concussion (SRC).
Design Meta-analysis was performed for PA/prescribed exercise interventions and a narrative synthesis for rest, cognitive activity and sleep. Risk of bias (ROB) was determined using the Scottish Intercollegiate Guidelines Network and quality assessed using Grading of Recommendations, Assessment, Development and Evaluations.
Data sources MEDLINE, Embase, APA PsycInfo, Cochrane Central Register of Controlled Trials, CINAHL Plus and SPORTDiscus. Searches were conducted in October 2019 and updated in March 2022.
Eligibility criteria Original research articles with sport-related mechanism of injury in >50% of study sample and that evaluated how PA, prescribed exercise, rest, cognitive activity and/or sleep impact recovery following SRC. Reviews, conference proceedings, commentaries, editorials, case series, animal studies and articles published before 1 January 2001 were excluded.
Results 46 studies were included and 34 had acceptable/low ROB. Prescribed exercise was assessed in 21 studies, PA in 15 studies (6 PA/exercise studies also assessed cognitive activity), 2 assessed cognitive activity only and 9 assessed sleep. In a meta-analysis of seven studies, PA and prescribed exercise improved recovery by a mean of −4.64 days (95% CI −6.69, –2.59). After SRC, early return to light PA (initial 2 days), prescribed aerobic exercise treatment (days 2–14) and reduced screen use (initial 2 days) safely facilitate recovery. Early prescribed aerobic exercise also reduces delayed recovery, and sleep disturbance is associated with slower recovery.
Conclusion Early PA, prescribed aerobic exercise and reduced screen time are beneficial following SRC. Strict physical rest until symptom resolution is not effective, and sleep disturbance impairs recovery after SRC.
Leddy (2013)
A Pilot Study of Changes in Functional Magnetic Resonance Imaging Activation, Physiology, and Symptoms
Purpose:
To compare functional magnetic resonance imaging (fMRI) activation patterns during a cognitive task, exercise capacity, and symptoms in postconcussion syndrome (PCS) patients who received exercise treatment (n = 4) with a PCS placebo stretching group (n = 4) and a healthy control group (n = 4).
Methods:
Subjects completed a math processing task during fMRI and an exercise treadmill test before (time 1) and after approximately 12 weeks (time 2). Exercise subjects performed aerobic exercise at 80% of the heart rate (HR) attained on the treadmill test, 20 minutes per day with an HR monitor at home, 6 days per week. The program was modified as the HR for symptom exacerbation increased.
Results:
At time 1, there was no difference in fMRI activation between the 2 PCS groups but healthy controls had significantly greater activation in the posterior cingulate gyrus, lingual gyrus, and cerebellum versus all PCS subjects (P < .05, corrected for multiple comparisons). At time 2, exercise PCS did not differ from healthy controls whereas placebo stretching PCS had significantly less activity in the cerebellum (P < .05 corrected) and in the anterior cingulate gyrus and thalamus (P < .001, uncorrected) versus healthy controls. At time 2, exercise PCS achieved a significantly greater exercise HR (P < .001) and had fewer symptoms (P < .0004) than placebo stretching PCS. Cognitive performance did not differ by group or time.
Conclusions:
Controlled aerobic exercise rehabilitation may help restore normal cerebral blood flow regulation, as indicated by fMRI activation, in PCS patients. The PCS symptoms may be related to abnormal cerebral blood flow regulation.
Leddy (2018)
Exercise is Medicine for Concussion
Sport-related concussion (SRC) is a physiological brain injury that produces cerebral and systemic effects, including exercise intolerance. Exercise intolerance after concussion is believed to be the result of autonomic nervous system (ANS) dysfunction. Ventilation is inappropriately low for the level of exercise intensity, raising arterial carbon dioxide (PaCO2) levels.
Elevated PaCO2 increases cerebral blood flow (CBF) out of proportion to exercise intensity, which is associated with symptoms that limit exercise performance. Thus, elevated exercise PaCO2 may signal incomplete recovery from SRC. This article reviews recent observational and experimental data and presents the evidence that subthreshold aerobic exercise normalizes the cerebrovascular physiological dysfunction and is “medicine” for patients with concussion and persistent postconcussive symptoms (PPCS).
It discusses the systematic evaluation of exercise tolerance after concussion using the Buffalo Concussion Treadmill Test (BCTT) and reviews the utility of the Buffalo Concussion Bike Test (BCBT), the data from which are used to establish an individualized heart rate “dose” of subthreshold exercise to safely speed recovery, which also may work in the acute recovery phase after SRC with the potential to reduce the incidence of PPCS. Evaluation and treatment approaches based on the physiology of concussion suggest that exercise is medicine for concussion, potentially adding a new dimension to concussion care to help safely speed recovery and prevent PPCS in some patients.
Leddy (2019)
A Preliminary Study of the Effect of Early Aerobic Exercise Treatment for Sport-Related Concussion in Males
Objective:
To study the effect of early prescribed aerobic exercise versus relative rest on rate of recovery in male adolescents acutely after sport-related concussion (SRC).
Design:
Quasi-experimental design.
Setting:
University sports medicine centers.
Participants:
Exercise group (EG, n = 24, 15.13 ± 1.4 years, 4.75 ± 2.5 days from injury) and rest group (RG, n = 30, 15.33 ± 1.4 years, 4.50 ± 2.1 days from injury).
Interventions:
Exercise group performed a progressive program of at least 20 minutes of daily subthreshold aerobic exercise. Rest group was prescribed relative rest (no structured exercise). Both groups completed daily online symptom reports (Postconcussion Symptom Scale) for 14 days.
Main Outcome Measures:
Days to recovery after treatment prescription. Recovery was defined as return to baseline symptoms, exercise tolerant, and judged recovered by physician examination.
Results:
Recovery time from initial visit was significantly shorter in EG (8.29 ± 3.9 days vs 23.93 ± 41.7 days, P = 0.048). Mixed-effects linear models showed that all symptom clusters decreased with time and that there was no significant interaction between treatment group and time. No EG participants experienced delayed recovery (>30 days), whereas 13% (4/30) of RG participants experienced delayed recovery.
Conclusions:
These preliminary data suggest that early subthreshold aerobic exercise prescribed to symptomatic adolescent males within 1 week of SRC hastens recovery and has the potential to prevent delayed recovery.
Leddy (2018)
Active recovery from concussion
Purpose of review
Recent studies are challenging the utility of prolonged rest as treatment for concussion and postconcussion syndrome (PCS). The purpose of this paper is to review the evidence for active recovery from concussion and PCS.
Recent findings
Emerging data identify the central role of autonomic nervous system (ANS) dysfunction in concussion pathophysiology. The exercise intolerance demonstrated by athletes after sport-related concussion may be related to abnormal ANS regulation of cerebral blood flow. As aerobic exercise training improves ANS function, sub-symptom threshold exercise treatment is potentially therapeutic for concussion. A systematic assessment of exercise tolerance using the Buffalo Concussion Treadmill Test has been safely employed to prescribe a progressive, individualized subthreshold aerobic exercise treatment program that can return patients to sport and work. Multiple studies are demonstrating the efficacy of an active approach to concussion management.
Summary
Sustained rest from all activities after concussion, so-called ‘cocoon therapy’, is not beneficial to recovery. Evidence supports the safety, tolerability, and efficacy of controlled sub-symptom threshold aerobic exercise treatment for PCS patients. Further study should determine the efficacy and optimal timing, dose, and duration of subthreshold aerobic exercise treatment acutely after concussion because early intervention has potential to prevent PCS.
Ayala & Heath (2020)
A sport-related concussion (SRC) results in short- and long-term deficits in oculomotor control; however, it is unclear whether this change reflects executive dysfunction and/or a performance decrement caused by an increase in task-based symptom burden.
Here, individuals with a SRC – and age- and sex-matched controls – completed an antisaccade task (i.e., saccade mirror-symmetrical to a target) during the early (initial assessment £12 days) and later (follow-up assessment <30 days) stages of recovery. Antisaccades were used because they require top-down executive control and exhibit performance decrements following an SRC. Reaction time (RT) and directional errors were included with pupillometry, because pupil size in the antisaccade task has been shown to provide a neural proxy for executive control. In addition, the SportConcussion Assessment Tool (SCAT-5) symptom checklist was completed prior to and after each oculomotor assessment to identify a possible task-based increase in symptomatology.
The SRC group yielded longer initial assessment RTs, more directional errors, and larger task-evoked pupil dilations (TEPD) than the control group. At the follow-up assessment, RTs for the SRC and control group did not reliably differ; however, the former demonstrated more directional errors and larger TEPDs. SCAT-5 symptom severity scores did not vary from the pre- to post-oculomotor evaluation for either initial or follow-up assessments. Accordingly, an SRC imparts a persistent executive dysfunction to oculomotor planning independent of a task-based increase in symptom burden.
These findings evince that antisaccades serve as an effective tool to identify subtle executive deficits during the early and later stages of SRC recovery.
