Time course of clinical and electrophysiological recovery after sport-related concussion
Prichep LS., McCrea M., Barr W., Powell M., Chabot RJ. Journal of Head Trauma Rehabilitation, 2012; ahead of print
Concussion research has shown that the typical time for cognitive and behavioral signs and symptoms to dissipate is within 7 to 10 days after an injury, however, researchers utilizing functional neuroimaging techniques (e.g., functional magnetic resonance imaging) have reported that neuronal dysfunction may be prolonged for up to several weeks. Therefore, the purpose of this study was to examine the differences in a calculated traumatic brain injury (TBI) index (via EEG patterns) and other clinical outcomes between patients with mild or moderate severity of concussion signs and symptoms as well as among patients with short (< 14 days) or delayed (> 14 days) return-to-play time. Sixty-five athletes who sustained a concussion were included in this study and went through a clinical evaluation (i.e., Concussion Symptom Inventory [CSI], Standardized Assessment of Concussion [SAC], Balance Error Scoring System, [BESS] and Automated Neuropsychological Assessment Metrics [ANAM]), and an electrophysiological evaluation to calculate the TBI index. These tests were conducted within 24 hours of the injury, and then at day 8 and day 45 after the injury. Concussion severity was based on specific concussion signs and symptoms using the CSI and SAC test (e.g., feeling in a fog, slowed down, memory impairment, loss of consciousness). Athletes were placed into either the mild concussion group (n = 51) or the moderate concussion group (n = 14). At the time of injury, patients with a moderate concussion had more severe signs and symptoms on the CSI and had poorer performances on the SAC and ANAM tests compared to the mild concussed group. However, at days 8 and 45 there were no differences in these outcomes between the two groups. The BESS test was not significantly different between the mild and moderate concussion groups at any of the time points. Despite the clinical outcomes not detecting differences at days 8 and 45 between patients with mild or moderate concussions the TBI index was higher among the moderately-concussed patients compared to the mildly-concussed group at all of the time points (at time of injury, day 8, and day 45). The sensitivity (positively diagnose a patient who has pathology) of the TBI index for moderate concussions at the time of injury was 55% and the specificity (not falsely diagnosing a healthy patient) was about 94%. Seventy-three percent of the patients returned to play within 14 days (mean = 5 days) and 27% took more than 14 days to return to play (mean = 20 days). At the time of injury, the TBI index was lower among patients that returned to play in less than 14 days (TBI index = 5) compared to the group who took 14 days or more to return to play (TBI index = 20).
Brain recovery after a concussion injury may extend beyond clinical recovery. Furthermore, the TBI index may be an objective indicator for concussion severity and predictive of recovery time (based on return-to-play time). This study offers preliminary data to suggest that the TBI index could be used as a prognostic tool however, a study with a larger sample size will be necessary. In this study the TBI index remained significantly elevated in the moderate group compared to mild concussed group up to 45 days after the injury. Based on these results, the TBI index could help differentiate severity of the concussion. However, we need to keep in mind that it only recognized a moderate concussion compared to a mild concussion 55% of the time. Based on this study the researchers suggest that measuring brain activity at the forehead could be used to calculate the TBI index on the sideline. This may help assess concussion severity and assist in determining return-to-play time. Do you have any experience with EEG? Is this a test you would consider using?
Written by: Jane McDevitt MS, ATC, CSCS
Reviewed by: Jeffrey Driban
Related Posts:Prichep LS, McCrea M, Barr W, Powell M, & Chabot RJ (2012). Time Course of Clinical and Electrophysiological Recovery After Sport-Related Concussion. The Journal of Head Trauma Rehabilitation PMID: 22588360