Temporary threshold shifts induced by low-pass and high-pass filtered noises in fetal sheep in utero.
Auditory brainstem responses (ABRs) were obtained from nine late gestational age fetal sheep in utero before and after a 16-h exposure to low-pass (cut-off frequency 1.0 kHz) and high-pass (cut-off frequency 1.0 kHz) noises (approximately 120 dB sound pressure level, recorded in air). Bone-conduction ABRs were elicited by broadband clicks and 0.5, 1.0 and 2.0 kHz tone bursts. Following low-pass noise exposure, ABR thresholds and wave IV latencies increased significantly for 0.5 and 1.0 kHz tone bursts. The high-pass noise exposure produced significant shifts in ABR thresholds and wave IV latencies only for the 1.0 kHz tone bursts. These findings confirm previous reports of low-frequency sound transmission into the fetal inner ear.
Huang
X
X
Department of Communication Processes and Disorders, University of Florida, Gainesville 32611, USA.
Gerhardt
K J
KJ
Abrams
R M
RM
Antonelli
P J
PJ
D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D005333:Fetus / Q000502:physiology*; D006317:Hearing Loss, Noise-Induced / Q000151:congenital / Q000209:etiology; D009622:Noise / Q000009:adverse effects; D011247:Pregnancy; D012756:Sheep