Fetal vibroacoustic stimulation test: vibrator response characteristics in pregnant sheep postmortem.

Publication/Presentation Date

2-1-1993

Abstract

OBJECTIVE: To determine the effect of small decreases in battery voltage on the sound pressure level and spectral features of sound within the uterus during vibroacoustic stimulation with a battery-powered electronic artificial larynx.

METHODS: In eight pregnant, recently sacrificed sheep, the fluid-borne, intra-amniotic sound pressures resulting from vibration of the abdominal wall with an electronic artificial larynx were compared with airborne sound pressures produced by an artificial larynx and measured at 50 cm.

RESULTS: At all frequencies, the intrauterine sound pressure was higher than the sound pressure in air. Decreasing battery voltage from 9 to 7 V resulted in a 5-18-dB decrease in intrauterine sound pressure at the electronic artificial larynx fundamental frequency and most overtones, but only a 4-8-dB decrease in the airborne signal. The results indicate that for frequencies relevant to fetal hearing, the reduction of sound pressure level caused by inadequate battery voltage may result in a difference in fetal response.

CONCLUSION: Routine verification of the function of a vibroacoustic device by means of a battery voltage check is recommended.

Volume

81

Issue

2

First Page

181

Last Page

184

ISSN

0029-7844

Disciplines

Medicine and Health Sciences

PubMedID

8423945

Department(s)

Department of Obstetrics and Gynecology

Document Type

Article

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