Research Articles

Incidence, Clinical Course, and Predictors of Prolonged Recovery Time Following Sport-Related Concussion in High School and College Athletes

Michael McCrea^a1 c1, Kevin Guskiewicz^a2a3a4, Christopher Randolph^a5, William B. Barr^a6, Thomas A. Hammeke^a7, Stephen W. Marshall^a3a4a8, Matthew R. Powell^a9, Kwang Woo Ahn^a10, Yanzhi Wang^a10 and James P. Kelly^a11

^a1 Departments of Neurosurgery and Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin

^a2 Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

^a3 Department of Orthopedics; University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

^a4 Injury Prevention Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

^a5 Department of Neurology, Loyola University Medical School, Maywood, Illinois

^a6 Departments of Neurology and Psychiatry, New York University School of Medicine, New York, New York

^a7 Department of Psychiatry and Behavioral Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin

^a8 Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

^a9 Department of Neuropsychology, Marshfield Clinic – Minocqua Center, Minocqua, Wisconsin

^a10 Division of Biostatistics, Medical College of Wisconsin, Milwaukee, Wisconsin

^a11 U.S. Department of Defense, National Intrepid Center of Excellence, Bethesda, Maryland

Abstract

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. (JINS, 2012, 18, 1–12)

(Received September 21 2011)

(Revised June 07 2012)

(Accepted June 07 2012)

Keywords

• Brain injury;
• Concussion;
• Neuropsychological tests;
• Sport injuries;
• Neurological disorders;
• Closed head injury

Correspondence:

^c1 Correspondence and reprint requests to: Michael McCrea, Department of Neurosurgery, Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Milwaukee, WI 53226. E-mail: mmccrea@mcw.edu