A recovery from enhancement of activation in auditory cortex of patients with idiopathic sudden sensorineural hearing loss

Abstract

Objective We previously reported enhanced activation of auditory cortex in patients with bilateral chronic inner-ear hearing loss. To determine whether this enhancement can exhibit a short-term alteration, we measured auditory evoked magnetic fields (AEFs) in patients with idiopathic sudden sensorineural hearing loss (ISSHL) in the acute phase (AP) and recovery phases (RPs). Methods We recorded AEFs in two unilateral ISSHL patients at three time points (AP, RP1, and RP2) using a whole-head neuromagnetometer. Tone bursts of 1 kHz were presented monaurally to the affected and healthy ear at four different intensities (40–70 dB HL). Results Both patients showed the enhancement of N100 m moment at AP and not at RPs in response to the affected ear stimulation, and stronger N100 m moment in ipsilateral than contralateral hemisphere in response to the healthy ear stimulation at AP. Conclusions Enhancement of N100 m amplitude occurs in ISSHL patients and disappears on the scale of days. Enhancement of activity in the auditory cortex derived from inner-ear hearing loss can thus exhibit short-term change. Significance The results of this study provide first evidence for a recovery from enhancement of activation in the auditory cortex following injury of peripheral hearing organ.