Premium
Noise‐induced inner ear damage in newborn and adult guinea pigs
Author(s) -
Falk Stephen A.,
Cook Reginald O.,
Haseman Joseph K.,
Sanders Gary M.
Publication year - 1974
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1288/00005537-197403000-00008
Subject(s) - cochlea , hair cell , organ of corti , outer hair cells , inner ear , group b , group a , anatomy , guinea pig , pathology , biology , chemistry , medicine , endocrinology
Abstract Two‐day (Group A), eight‐day (Group B), and eight‐month (Group C) old guinea pigs were exposed to 30 continuous hours of white noise at 119–120 db SPL. One month later pathology of the organ of Corti was evaluated and quantitated by use of the surface preparation technique. Percent cell damage was determined for outer hair, inner hair, outer pillar, and inner pillar cells at each of the four turns of the cochlea and for the cochlea as a whole. Comparisons of pathology of each cell type were made between groups. Mean percent outer hair cell damage per cochlea (± 1 S.E.) was 23.72 ± 3.69 for Group A, 36.98 ± 5.76 for Group B, and 7.24 ± 1.75 for Group C. There was no significant difference in outer hair cell damage between Groups A and B. Outer hair cells of Group A were significantly more damaged than those of Group C when damage in the cochlea as a whole was considered due to significantly greater damage in Group A at three and one half turns; likewise, outer hair cells of Group B were significantly more damaged than those of Group C when damage in the cochlea as a whole was considered due to significantly greater damage in Group B at two and one half and at three and one half turns. A similar effect was observed in terms of pathology of inner hair cells and pillar cells: there was a trend toward increased damage in animals of Groups A and B compared with C. Group C showed no outer or inner pillar cell damage, and only one of six animals had alterations in inner hair cells. In contrast, outer and inner pillar cells were damaged in Groups A and B, and four of six animals of Group A and six of eight of Group B showed inner hair cell damage. Recent electrophysiological and audiometric studies are discussed which, with the results of the present study, indicate greater susceptibility of young cochleas when compared with older cochleas, to noise‐induced physiological and pathological alterations. It would seem medically prudent to take special precautions to avoid exposing newborns to excessive noise.