Biophysical linkage between MRI and EEG coherence in closed head injury.

Using conventional MRI procedures, nuclear magnetic resonance (NMR) of brain water proton (1H) T2 relaxation times and EEG coherence were obtained from two independent groups of closed head injured (CHI) patients and a group of normal control subjects. Statistically significant intercorrelations were observed between 1H T2 relaxation times of the cortical gray and white matter and EEG coherence. The analyses showed that lengthened 1H T2 relaxation times of the cortical gray and white matter were related to: (1) decreased EEG coherence between short interelectrode distances (e.g., 7 cm) and increased EEG coherence between long interelectrode distances (e.g., 28 cm), (2) differences in EEG frequency in which T2 relaxation time was most strongly related to the gray matter in the delta and theta frequencies in CHI patients, and (3) increased T2 relaxation time and decreased short-distance EEG coherence were related to reduced cognitive function. The results were interpreted in terms of reduced integrity of protein/lipid neural membranes and the efficiency and effectiveness of short- and long-distance neural synchronization following traumatic brain injury.