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

Correlations between neuropsychological test results and P300 latency during silent-count and button-press tasks in post-traumatic brain injury patients.

To evaluate the correlations between memory function and intelligence and event-related potential, the P300 component for different tasks was studied for 30 post-traumatic brain injury patients (mean age 31.6 ± 13.7 years; 23 male and 7 female). Memory function, intelligence, and depression were measured by using the Mini-Mental State Examination, the revised Wechsler Adult Intelligence Scale and the Self-Rating Depression Scale, respectively. P300 latency was measured during silent-count and button-press tests at three midline scalp (Fz, Cz, and Pz) sites for all subjects by using an auditory ‘odd-ball’ paradigm. Neuropsychological memory score was predicted by intelligence score, but neurophysiological P300 latency was predicted by memory score for the silent-count test and by intelligence score for the button-press test. These results show that the P300 event-related potential component is sensitive to the diverse nature of cognitive deficits in post-traumatic brain injury patients during different types of discrimination tasks. However, future research is necessary to replicate and extend these findings

Motor learning of hands with auditory cue in patients with Parkinson’s disease

In the present research, changes in motor cortex function were observed in relation to repetitive, voluntary thumb movement (training) in patients with Parkinson’s disease (PD) and normal control subjects. Changes in the direction of thumb movement due to motor evoked potential (MEP) by transcranial magnetic stimulation (TMS), after motor training with and without rhythmic sound, were measured using a strain gauge for 12 patients with PD and 9 normal control subjects. PD patients who experienced the freezing phenomena showed poor change in direction of TMS-induced movement after self-paced movement; however, marked change in direction of TMS-induced movement was observed after training with auditory cue. PD patients who had not experienced the freezing phenomena showed positive effects with the auditory cue, producing similar results as the normal control subjects. Two routes for voluntary movement are available in the nervous system. The decreased function of basal ganglia due to PD impaired the route from the basal ganglia to the supplementary motor cortex. These data suggest that the route from sensory input to cerebellum to premotor cortex could compensate for the decreased function of the route via the basal ganglia to the premotor cortex. Once change in the motor cortex occurred, such change persisted even after the interruption of training. These phenomena suggest that motor memory can be stored in the motor cortex