Persistent postconcussion syndrome: The structure of subjective complaints after mild traumatic brain injury

Abstract

Objective: To examine the structure of persistent postconcussive symptoms in a sample of patients with mild traumatic brain injury. Design: Multivariate discriminant analysis in a series of 50 consecutive clinical referrals evaluated for postconcussive symptoms, neuropsychological functioning, and personality and emotional functioning at least 3 months after injury; follow-up information regarding level of disability was obtained for 37 patients at least 1 year after injury. Setting: Neuropsychology clinic affiliated with a comprehensive brain trauma rehabilitation center. Patients: 50 consecutively referred patients with a diagnosis of mild traumatic brain injury referred by physicians, rehabilitation nurses, or attorneys because of persistent deficits or subjective complaints consistent with a postconcussion syndrome. Main Outcome Measure: Postconcussive symptoms endorsed on the Post Mild Traumatic Brain Injury Symptom Checklist. Results: Four factors consisting of multiple symptoms were identified: cognitive factor, affective factor, somatic factor, and sensory factor. Using these four factors, K-means cluster analysis of subjects was applied to classify patients. Patient clusters consisted of those with minimal symptoms, those with primarily cognitive-affective symptoms, those with prominent somatic symptoms, and those with severe global symptoms (P = .000). Patient symptom clusters were largely unrelated to neurological or neuropsychological functioning. The presence of chronic disability and resumption of productive functioning differed significantly among groups (P = .003). Conclusions: Subjective complaints provide clinically meaningful information and are strongly related to the nature and extent of disability after mild traumatic brain injury. Characterization of a single postconcussive syndrome may be misleading, and it may be more meaningful to define a number of postconcussive syndromes with differing symptom profiles and recovery.