Neuropsychological correlates of basal ganglia and medial temporal lobe NAA/Cho reductions in traumatic brain injury

Background: Proton magnetic resonance spectroscopy can assess neurochemical sequelae in traumatic brain injury. Metabolic abnormalities are present in the acute or subacute period in patients with traumatic brain injury and correlate with outcome on clinical scales. Objective: To investigate the use of proton magnetic resonance spectroscopy in detecting possible gray subcortical neurochemical impairments and their relationship with neuropsychological performance. Design: Group comparisons and correlations of brain metabolites with clinical and neuropsychological variables. Patients and Methods: Metabolite concentrations were acquired from voxels localized to the basal ganglia and medial temporal region in 20 patients with long-term moderate and severe traumatic brain injury and 20 matched control subjects. Both groups under-went neuropsychological assessment. Results: N-acetylaspartate-choline-containing compounds ratios were decreased in patients in the basal ganglia (t=-3.28, P=.002) and medial temporal region (t=-3.52, P=.001). The basal ganglia ratio correlated to measures of speed, motor scanning, and attention. Conclusion: Patients with long-term TBI present a regional correlation pattern that may help identify the neurological basis of cognitive sequelae in traumatic brain injury.