Changes in CAP adaptation in experimentally induced endolymphatic hydrops.
OBJECTIVE
To determine the effect of experimentally induced endolymphatic hydrops (ELHs) on compound action potential (CAP) adaptation.


METHODS
The CAP was recorded 1 month after surgical treatment to produce ELH. The CAP threshold in response to click stimuli showed no significant differences between the hydropic and control groups. The CAP was elicited from the retroauricular-exposed round window using a silver ball electrode. Click trains consisting of 10 clicks with an interclick interval (Deltat) of either 4 or 8 ms were delivered through a loudspeaker placed in front of the animals' ears. The patterns of adaptation to these click trains were evaluated as functions of Deltat and intensity level.


RESULTS
An abnormal pattern of CAP adaptation was observed in hydropic ears.


CONCLUSIONS
These findings suggest that early ELH influences CAP adaptation.
Kinoshita
Hirotsugu
H
Department of Otolaryngology, St. Marianna University School of Medicine, 2-16-1, Sugao, Miyamae-ku, 216-8511, Kawasaki, Japan.
Ochi
Kentaro
K
Sugiura
Natsuki
N
Kenmochi
Mutsumi
M
Nishino
Hirohito
H
Ohashi
Toru
T
D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold / Q000187:drug effects / Q000502:physiology*; D003051:Cochlea / Q000473:pathology / Q000503:physiopathology; D003056:Cochlear Nerve / Q000187:drug effects / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000502:physiology; D018159:Endolymphatic Hydrops / Q000473:pathology / Q000503:physiopathology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D006168:Guinea Pigs; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology*; D008297:Male; D010897:Pitch Discrimination / Q000187:drug effects / Q000502:physiology*; D012016:Reference Values; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*