Growth of evoked potential amplitude in neonatal chicks exposed to intense sound.
The recovery of auditory function at selected intervals following exposure to a 0.9 kHz tone for 48 h at 120 dB SPL is described in neonatal chicks. Evoked potentials recorded from the nucleus magnocellularis were used to measure threshold sensitivity and peak-to-peak response amplitude as a function of stimulus intensity. The relation between evoked-response amplitude and stimulus intensity was nearly linear in control animals. However, at 10 days post exposure, the evoked response in mid-range frequencies showed a severe threshold shift and an abnormally rapid growth in amplitude. At 3 days post exposure, the rate of growth was nearly identical to that measured in control animals and threshold sensitivity showed considerable recovery. Current theories of amplitude-intensity growth and studies of basilar papilla damage and repair following intense sound exposure were applied in the analysis of these results.
Pugliano
F A
FA
Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia.
Pribitikin
E
E
Adler
H J
HJ
Saunders
J C
JC
D000161:Acoustic Stimulation; D000818:Animals; D000831:Animals, Newborn; D001309:Auditory Threshold / Q000502:physiology; D001489:Basilar Membrane / Q000473:pathology; D002645:Chickens; D004195:Disease Models, Animal; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D006317:Hearing Loss, Noise-Induced / Q000503:physiopathology*; D013997:Time Factors