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


CONCLUSIONS
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.
Morita
T
T
Department of Otolaryngology, Shizuoka General Hospital, 420-8527 Shizuoka, Japan. morita@ent.kuhp.kyoto-u.ac.jp
Hiraumi
H
H
Fujiki
N
N
Naito
Y
Y
Nagamine
T
T
Fukuyama
H
H
Ito
J
J
D000161:Acoustic Stimulation; D000208:Acute Disease; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D001306:Auditory Pathways / Q000502:physiology; D001307:Auditory Perception / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology*; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*; D013997:Time Factors; D015854:Up-Regulation / Q000502:physiology