Measurement of transcallosal inhibition in traumatic brain injury by transcranial magnetic stimulation.

PRIMARY OBJECTIVE To study whether transcallosal inhibition (TCI) can evaluate the severity of traumatic brain injury (TBI). RESEARCH DESIGN Case-control study. METHODS AND PROCEDURES Twenty patients with a chronic TBI and 20 control subjects were studied. The following transcranial magnetic stimulation parameters were checked; resting motor threshold, central motor latency times, onset latency of TCI, duration of TCI, transcallosal conduction times and amount of TCI. The severity of TBI was evaluated using the Glasgow Coma Scale (GCS). MAIN OUTCOME AND RESULTS The amount of TCI was significantly lower in the patients than the control subjects (p < 0.001). The amount of TCI was highly correlated with the GCS (r = 0.787, p < 0.001). CONCLUSION An assessment of TCI was found to be a more sensitive and useful method for an evaluation of the severity of TBI.