William B. Barr

Standard regression-based methods for measuring recovery after sport-related concussion

Clinical decision making about an athletes return to competition after concussion is hampered by a lack of systematic methods to measure recovery. We applied standard regression-based methods to statistically measure individual rates of impairment at several time points after concussion in college football players. Postconcussive symptoms, cognitive functioning, and balance were assessed in 94 players with concussion (based on American Academy of Neurology Criteria) and 56 noninjured controls during preseason baseline testing, and immediately, 3 hr, and 1, 2, 3, 5, and 7 days postinjury. Ninety-five percent of injured players exhibited acute concussion symptoms and impairment on cognitive or balance testing immediately after injury, which diminished to 4% who reported elevated symptoms on postinjury day 7. In addition, a small but clinically significant percentage of players who reported being symptom free by day 2 continued to be classified as impaired on the basis of objective balance and cognitive testing. These data suggest that neuropsychological testing may be of incremental utility to subjective symptom checklists in identifying the residual effects of sport-related concussion. The implementation of neuropsychological testing to detect subtle cognitive impairment is most useful once postconcussive symptoms have resolved. This management model is also supported by practical and other methodological considerations.

An integrated review of recovery after mild traumatic brain injury (MTBI): implications for clinical management.

The diagnosis and treatment of mild traumatic brain injury (MTBI)have historically been hampered by an incomplete base of scientific evidence to guide clinicians. One question has been most elusive to clinicians and researchers alike: What is the true natural history of MTBI? Fortunately, the science of MTBI has advanced more in the last decade than in the previous 50 years, and now reaches a maturity point at which the science can drive an evidence-based approach to clinical management. In particular, technological advances in functional neuroimaging have created a powerful bridge between the clinical and basic science of MTBI in humans. Collectively, findings from clinical, basic science, and functional neuroimaging studies now establish a foundation on which to build integrative theories and testable hypotheses around a comprehensive model of MTBI recovery. We review the current scientific literature on postconcussion symptom recovery, neuropsychological outcome, and neurophysiological healing after MTBI. Special emphasis is placed on how the new evidence base can help guide clinicians in the evaluation and management of military-related MTBI.

Sensitivity and specificity of standardized neurocognitive testing immediately following sports concussion

Neuropsychology, with its emphasis on standardized and empirically based methods, has made a number of scientific contributions to address growing concerns about concussions resulting from sports injuries. This study employs a test-retest paradigm to determine the immediate effects of concussion in high-school and college athletes. The Standardized Assessment of Concussion (SAC) was administered to 1,313 male athletes prior to the beginning of the competitive season. Reliable change indices and multiple regression models were computed on retest scores obtained from 68 noninjured athletes who were readministered the SAC at either 60 or 120 days following baseline testing. Receiver operating characteristic (ROC) curve analyses were used to test these models with data obtained on 50 athletes tested immediately following concussion. The results indicate that a decline of I point on the SAC at retesting classified injured and noninjured participants with a level of 94% sensitivity and 76% specificity. The RCI and multiple regression models provided comparable levels of group classification, but provided cut-offs that are conservative for use with this population. The results support and extend previous research findings indicating that the SAC is a valid instrument for detecting the immediate effects of mild traumatic brain injury.

Incidence, clinical course, and predictors of prolonged recovery time following sport-related concussion in high school and college athletes.

Sport-related concussion (SRC) is typically followed by clinical recovery within days, but reports of prolonged symptoms are common. We investigated the incidence of prolonged recovery in a large cohort (n = 18,531) of athlete seasons over a 10-year period. A total of 570 athletes with concussion (3.1%) and 166 controls who underwent pre-injury baseline assessments of symptoms, neurocognitive functioning and balance were re-assessed immediately, 3 hr, and 1, 2, 3, 5, 7, and 45 or 90 days after concussion. Concussed athletes were stratified into typical (within 7 days) or prolonged (> 7 days) recovery groups based on symptom recovery time. Ten percent of athletes (n = 57) had a prolonged symptom recovery, which was also associated with lengthier recovery on neurocognitive testing (p < .001). At 45-90 days post-injury, the prolonged recovery group reported elevated symptoms, without deficits on cognitive or balance testing. Prolonged recovery was associated with unconsciousness [odds ratio (OR), 4.15; 95% confidence interval (CI) 2.12-8.15], posttraumatic amnesia (OR, 1.81; 95% CI, 1.00-3.28), and more severe acute symptoms (p < .0001). These results suggest that a small percentage of athletes may experience symptoms and functional impairments beyond the typical window of recovery after SRC, and that prolonged recovery is associated with acute indicators of more severe injury.

Changes in depression and anxiety after resective surgery for epilepsy

Objective: To determine changes in depression and anxiety after resective surgery. Methods: Data from subjects enrolled in a prospective multicenter study of resective epilepsy surgery were reviewed with the Beck Psychiatric Symptoms Scales (Beck Depression Inventory [BDI] and Beck Anxiety Inventory [BAI]) and Composite International Diagnostic Interview (CIDI) up to a 24-month period. χ2 analyses were used to correlate proportions. Results: A total of 358 presurgical BDI and 360 BAI results were reviewed. Moderate and severe levels of depression were reported in 22.1% of patients, and similar levels of anxiety were reported by 24.7%. Postoperative rates of depression and anxiety declined at the 3-, 12-, and 24-month follow-up periods. At the 24-month follow-up, moderate to severe levels of depression symptoms were reported in 17.6 and 14.7% of the patients who continued to have postoperative seizures. Moderate to severe depression and anxiety were found in 8.2% of those who were seizure-free. There was no relationship, prior to surgery, between the presence or absence of depression and anxiety and the laterality or location of the seizure onset. There were no significant relationships between depression or anxiety at 24-month follow-up and the laterality or location of the surgery. Conclusions: Depression and anxiety in patients with refractory epilepsy significantly improve after epilepsy surgery, especially in those who are seizure-free. Neither the lateralization nor the localization of the seizure focus or surgery was associated with the risk of affective symptoms at baseline or after surgery.

EFFECTS OF A SYMPTOM‐FREE WAITING PERIOD ON CLINICAL OUTCOME AND RISK OF REINJURY AFTER SPORT‐RELATED CONCUSSION

OBJECTIVEThis study is the first to investigate the influence of a symptom-free waiting period (SFWP) on clinical outcome and risk of repeat injury after sport-related concussion. METHODSThis was a prospective, nonrandomized study of 16 624 player seasons from 1999 to 2004, including a cohort of 635 concussed high school and college athletes grouped on the basis of an SFWP or no SFWP observed after their concussion. Clinical outcome in symptoms, cognitive functioning, and postural stability 45 and 90 days postinjury was compared with preinjury baseline. Data on SFWP and same-season repeat concussion were recorded. RESULTSAn SFWP was observed in 60.3% of cases. There were no significant differences between the SFWP and no SFWP groups in acute injury characteristics or clinical outcome with respect to symptom recovery or postinjury performance on formal neuropsychological and balance testing. Most repeat concussions (79.2%) occurred within 10 days of the initial injury. The rate of repeat concussion was actually higher in the SFWP group (6.49%) than the no SFWP group (0.90%) (P < 0.005), but the repeat concussion subgroups SFWP was 2.82 days shorter (95% confidence interval, 0.61–5.03; P < 0.01) and these athletes resumed participation 3.55 days sooner (95% confidence interval, 0.06–7.04; P < 0.05) than those in the SFWP group in which there was no repeat concussion. CONCLUSIONOur findings suggest that an SFWP did not intrinsically influence clinical recovery or reduce risk of a repeat concussion. The overall risk of same-season repeat concussion seems to be relatively low, but there may be a period of vulnerability that increases risk of repeat concussion during the first 7 to 10 days postinjury. Further study is required to investigate this preliminary finding and help determine whether this risk can be reduced further with specific injury-management strategies.

Acute effects and recovery after sport-related concussion: a neurocognitive and quantitative brain electrical activity study.

ObjectiveTo investigate the clinical utility and sensitivity of a portable, automatic, frontal quantitative electroencephalographic (QEEG) acquisition device currently in development in detecting abnormal brain electrical activity after sport-related concussion. DesignThis was a prospective, non-randomized study of 396 high school and college football players, including cohorts of 28 athletes with concussion and 28 matched controls. All subjects underwent preseason baseline testing on measures of postconcussive symptoms, postural stability, and cognitive functioning, as well as QEEG. Clinical testing and QEEG were repeated on day of injury and days 8 and 45 postinjury for the concussion and control groups. Main Outcomes and ResultsThe injured group reported more significant postconcussive symptoms during the first 3 days postinjury, which resolved by days 5 and 8. Injured subjects also performed poorer than controls on neurocognitive testing on the day of injury, but no differences were evident on day 8 or day 45. QEEG studies revealed significant abnormalities in electrical brain activity in the injured group on day of injury and day 8 postinjury, but not on day 45. ConclusionsResults from the current study on clinical recovery after sport-related concussion are consistent with early reports indicating a typical course of full recovery in symptoms and cognitive dysfunction within the first week of injury. QEEG results, however, suggest that the duration of physiological recovery after concussion may extend longer than observed clinical recovery. Further study is required to replicate and extend these findings in a larger clinical sample, and further demonstrate the utility of QEEG as a marker of recovery after sport-related concussion.

Worsening of quality of life after epilepsy surgery Effect of seizures and memory decline

Background: Surgery for intractable temporal lobe epilepsy usually controls seizures and improves health-related quality of life (HRQOL), but some patients experience continued seizures, memory decline, or both. The relative impact of these unfavorable outcomes on HRQOL has not been described. Methods: We studied seizure control, memory change, and HRQOL among 138 patients in the Multicenter Study of Epilepsy Surgery (MSES), an ongoing, prospective study of epilepsy surgery outcomes. Seizure remission at 2 years and 5 years was prospectively determined based upon regularly scheduled follow-up calls to study patients throughout the follow-up period. HRQOL was assessed annually using the Quality of Life in Epilepsy Inventory (QOLIE-89). Memory decline was determined by change in verbal delayed recall from baseline to the 2- or 5-year follow-up. Results: HRQOL improved in patients who were in remission at the 2-year or 5-year follow-up, regardless of memory outcome. Among those not in remission at both 2 and 5 years (25/138, 18%), HRQOL remained stable when memory did not decline (14/138, 10%), but HRQOL declined when memory did decline (11/138, 8%). These 11 patients had baseline characteristics predictive of poor seizure or memory outcome. Declines were most apparent on HRQOL subscales assessing memory, role limitations, and limitations in work, driving, and social activities. Conclusions: After temporal resection, health-related quality of life (HRQOL) improves or remains stable in seizure-free patients despite memory decline, but HRQOL declines when persistent seizures are accompanied by memory decline. These results may be useful in presurgical counseling and identifying patients at risk for poor psychosocial outcome following surgery.

Degree of handedness and cerebral dominance

Objective: To examine the relationship between the degree of handedness and hemispheric language dominance in patients with epilepsy. Methods: The authors examined the relationship between degree of handedness and hemispheric language dominance in 174 epilepsy surgery candidates using the intracarotid amobarbital procedure and results from a modified version of the Edinburgh Handedness Inventory. Results: The incidence of atypical language dominance increased linearly with the degree of left-handedness, from 9% in strong right-handers (laterality quotient [LQ] = +100) to 46% in ambidextrous individuals and 69% in strong left-handers (LQ = −100). Conclusions: The incidence of atypical language dominance depends not only on the direction but also on the degree of handedness. In addition, direction of language dominance varies with hemisphere of seizure focus and degree of handedness. A familial history of sinistrality may have an additional effect on the likelihood of atypical dominance.

Measuring brain electrical activity to track recovery from sport-related concussion

Primary objective: To follow recovery from concussion in a sample of athletes using an electroencephalographic (EEG) index of quantitative brain activity developed previously on an independent Emergency Department (ED) sample of head-injured subjects with traumatic brain injury. Methods and procedures: EEG recordings from five frontal electrode sites were obtained on 59 injured athletes and 31 controls at the time of injury and at 8 and 45 days afterward. All subjects also completed standardized clinical assessment of post-concussion symptoms, postural stability and cognitive functioning at injury and 8 and 45 days post-injury. Results: Abnormalities in clinical assessment measures were observed in injured subjects only at time of injury. Statistical analysis of brain electrical activity measures with the ED-based algorithm revealed significant differences between injured athletes vs controls at the time of injury and at day 8. Measures from the two groups did not differ on day 45. Conclusions: This study demonstrated that an algorithm of brain electrical activity developed on an independent sample of ED subjects with head injury is sensitive to the effects of sport-related concussion. Using this algorithm, abnormal features of brain electrical activity were detected in athletes with concussion at the time of injury and persisted beyond the point of recovery on clinical measures.