Balance And Cognitive Recovery Following Concussion Injury Is Associated With Initial Symptom Severity

Abstract

INTRODUCTION: Symptoms remain a primary way to monitor recovery from concussion injury. However, the association between subjective symptoms and objective measures of balance and cognition is not entirely understood. PURPOSE: To examine the association between objective and subjective measures during recovery from concussion injury. The primary hypothesis is to describe changes in cognition, balance, and symptom severity over a one month timeframe following concussion injury. A secondary hypothesis is that symptom severity at time of injury will be associated with objective measures during the recovery period. METHODS: Fifty-one young adults (18.01±5.96 years old) who recently sustained a concussion completed a battery of four cognitive tests, eight balance tests, and a 22 item symptom report using a commercially available assessment tool (ClearEdge, Quadrant Biosciences Inc; Syracuse, NY). All subjects completed test 1, on average, 5.45 ± 3.53 days after injury, and test 2, 23.06 ± 10.92 days following test 1. Group comparisons (repeated measures ANOVA or T-Test) and effect sizes (Cohen’s d) were used to compare recovery across time. To address the secondary hypothesis, those within the group reporting low symptom severity (symptoms <10; n=18) and high symptom severity (symptoms > 40; n=14) were compared. RESULTS: Across the sample, symptom severity at initial testing ranged from 0-89. Statistically significant differences between test 1 and 2 were seen for all cognitive tests (p<0.001) and 1 of the 8 balance tests (p=0.028). When comparing symptom severity groups, significant differences (p<0.05) at the first testing session were seen on 3 cognitive tests and 2 balance tests. No differences were seen between groups at test 2. The low symptom severity group had no changes in cognitive or balance scores between test 1 and 2. The high symptom group had large effects sizes towards improvement on Tandem Stance Eyes Closed (d=1.16), and Simple Reaction Time 2 (d=1.36). CONCLUSION: Symptom severity is associated with objective measures of balance and cognition during the recovery period. The low symptom group appears to have reached full recovery prior to initial testing. The high symptom group showed signs of injury at initial testing with large changes in cognitive and balance performance at re-test.