We examined 16 patients with unilateral tongue deviation using magnetic stimulator in order to evaluate central hypoglossal nerve palsy following brain injury.

Surface recording electrodes were placed at the apex and anterolateral one thirds of tongue. Magnetic stimulation was performed at vertex and occiput. On occiput stimulation, the mean latency was 3.77⁑0.36 msec in affected side and 3.89⁑0.47 msec in sound side for male patients, and 3.94⁑0.61 msec, 3.90⁑0.55 msec respectively for female patients. The mean amplitude was 0.85⁑0.63 mV in affected side and 2.64⁑2.32 mV in sound side for male patients and 1.00⁑0.23 mV, 3.56⁑0.40 mV respectively for female patients. There was significant difference between affected side and sound side for amplitude.

On vertex stimulation, the mean latency was 8.61⁑0.83 msec in affected side and 7.50⁑0.80 msec in sound side for male patients, and 9.66⁑1.14 msec, 6.48⁑0.44 msec respectively for female patients. The mean amplitude was 0.77⁑0.59 mV in affected side and 1.23⁑1.08 mV in sound side for male patients and 0.52⁑0.23 mV, 1.15⁑0.64 mV respectively for female patients. There was significant difference between affected side and sound side for latency and amplitude.