Patterns of early emotional and neuropsychological sequelae after mild traumatic brain injury.

Although mild traumatic brain injury (mTBI) is now recognized as a major health issue, there have been relatively few studies of its acute effects. Previous studies of mTBI assessed at 1 week or less post-injury have produced inconsistent results, spanning reports of no ill effects to findings of robust dysfunction. These gross disparities reflect study differences such as the criteria for mTBI diagnosis and selection of comparison groups. In consideration of these issues, this study investigated outcome in the first 96 hours after injury in adolescents and adults ages 12-30 years with mTBI (n=73) compared with orthopedically injured (OI, n=65) and typically developing controls (TDC, n=40). The mTBI group reported significantly greater general psychological distress, post-concussion symptom severity, and post-traumatic stress severity than OI (all p<0.0001) and TDC (all p<0.0001); the OI and TDC groups responded similarly on these variables. There was a significant Group × Age interaction on the Total score (p<0.009), and the Cognitive (p=0.01) and Somatic (p<0.032) subscales of the Rivermead Post Concussion Symptoms Questionnaire where increasing symptom severity was associated with increasing age in the mTBI group. On neuropsychological assessment, the mTBI group performed significantly more poorly compared with OI for Verbal Selective Reminding Test (delayed recall, p=0.0003) and Symbol-Digit Modalities Test (SDMT written p=0.03; oral, p=0.001). The TDC group more robustly outperformed the mTBI group on these measures and also on the Brief Visuospatial Memory Test (delayed recall, p<0.04), Letter Fluency (p<0.02), and Category Switching (p<0.04). The TDC group outperformed the OI group on SDMT and Letter Fluency. These findings are consistent with previous reports of acute deficits in episodic memory and processing speed acutely after mTBI. Notably, however, these data also demonstrate the challenges of comparison group selection because differences were also found between the TDC and OI groups.