AUDITORY PATHWAY PLASTICITY IN ADULT HUMANS AFTER UNILATERAL IDIOPATHIC SUDDEN SENSORINEURAL HEARING-LOSS

We recorded auditory evoked magnetic fields from 8 patients with unila teral, idiopathic, sudden, sensorineural hearing loss and from 8 healt hy controls, using a 122-channel whole-scalp neuromagnetometer. The st imuli were 50-ms 1-kHz tons bursts, delivered to the healthy ear at in terstimulus intervals (ISIs) of 1, 2, 4, 8, and 16 s. On average, as i n normal-hearing controls, the dipole moments and the latencies of N10 0m, the 100-ms response, increased as a function of ISI over both hemi spheres to left- and right-ear stimulation. Four patients had shorter response latencies and 4 had stronger dipole moments over the hemisphe re ipsilateral to the stimulation. In 3 patients, one additional sourc e was observed over the anterolateral right hemisphere and another nea r head midline. These findings suggest that unilateral sensorineural h earing loss may modify information processing in the central auditory pathways.