Effect of impulse noise on the auditory brainstem response of the fetal sheep and the adult ewe: case study.
Auditory brainstem responses (ABR) were obtained from a sheep fetus in utero and from a nonpregnant ewe before and after a noise exposure generated by 10 105-mm howitzer impulses (160-166 dB peak pressure). Fetal ABR thresholds shifted by less than 15 dB, whereas the adult thresholds shifted more than 50 dB. Comparison of exposed and nonexposed fetal cytocochleograms revealed minimal sensory cell loss in two age-matched animals. Although fetal ABR threshold shifts were noted in this study, the magnitude of shift was modest when compared to the significant elevation of the adult ABR thresholds.
Pierson
L L
LL
Department of Obstetrics and Gynecology Perinatology Research Laboratory, University of Florida, Gainesville 32611.
Gerhardt
K J
KJ
Abrams
R M
RM
Griffiths
S K
SK
Peters
A J
AJ
D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D005333:Fetus / Q000502:physiology*; D009622:Noise; D012680:Sensitivity and Specificity; D012756:Sheep / Q000502:physiology*