['To determine whether proton MRS (1H-MRS) neurochemical measurements predict neuropsychological outcome of patients with traumatic brain injury (TBI).', 'Although clinical indices and conventional imaging techniques provide critical information for TBI patient triage and acute care, none accurately predicts individual patient outcome.', 'The authors studied 14 patients with TBI soon after injury (45+/-21 days postinjury) and again at 6 months (172+/-43 days) and 14 age-, sex-, and education-matched control subjects. N-acetylaspartate (NAA), creatine, and choline were measured in normal-appearing occipitoparietal white and gray matter using quantitative 1H-MRS. Outcome was assessed with the Glasgow Outcome Scale (GOS) and a battery of neuropsychological tests. A composite measure of neuropsychological function was calculated from individual test z-scores probing the major functional domains commonly impaired after head trauma.', 'Early NAA concentrations in gray matter predicted overall neuropsychological performance (r = 0.74, p = 0.01) and GOS (F = 11.93, p = 0.007). Other metabolite measures were not related to behavioral function at outcome.'] Does quantitative proton MRS predict outcome after traumatic brain injury?