Auditory evoked magnetic fields in stroke

Auditory magnetic fields evoked by noise/square-wave sequences, presented once every 2.2 s, were recorded in eight subjects who had had a stroke in the auditory cortex or in its vicinity. In two subjects with large temporoparietal lesions, the magnetic 100 ms deflection (N100m) was absent over the damaged side. In one subject with a large but less deep temporoparietal lesion, a small N100m could be discerned on the defective side. The latency of N100m was increased in patients with frontal lesions. Small damages in the vicinity of the supratemporal plane had no effect on N100m. Magnetoencephalography is particularly applicable to outpatient studies of stroke.