Temporary threshold shift in ABRs and DPOAEs following noise exposure in Long-Evans rats.
Murphy WJ; van Campen LE
J Acoust Soc Am 2001 May; 109(5):2373
In conjunction with a study of reactive oxygen species induced damage in Long-Evans rats [van Campen et al., ARO abstracts (2001)], the progressions of temporary shifts in auditory brainstem response thresholds and distortion product otoacoustic emission input/output functions were analyzed. Thirty-five rats were exposed to 2 h of 120-dB SPL band-limited noise (7.5-15 kHz). ABR and DPOAE measurements were collected at 1-, 3-, 8-, 72-, and 672-h post-exposure for seven rats per condition. One sham-exposed rat was included in each exposure group. Thresholds for ABR elicited by tone bursts (2, 4, 8, 16, 32 kHz) exhibited the greatest threshold shifts for the 8-, 16- and 32-kHz stimuli. Recovery following noise exposure was greatest for the 72-h group with a lesser recovery for the 672-h group. The DPOAE thresholds (level of the f2 primary stimulus where LDPOAE was 5 dB above the noise floor) exhibited no significant difference for the 72- and 672-h groups. However, the input/output functions for the 72 group exhibited more DPOAE energy than the 672-h group.
Hearing-level; Hearing-loss; Hearing-acuity; Health-surveys; Age-factors; Age-groups; Information-retrieval-systems; Physical-examination; Racial-factors; Sex-factors; Audiological-testing; Audiometry
William J. Murphy, NIOSH, Hearing Loss Prevention Sect., 4676 Columbia Pkwy., Cincinnati, OH 45226-1998
Journal of the Acoustical Society of America