Maternal sound level device and method for protecting fetal hearing

Abstract

The present invention is a maternal sound level device that functions to protect fetal hearing by alerting the mother whenever her fetus is exposed to sound pressure levels (SPL) which exceed predetermined levels. The device is comprised of a microphone (14) for SPL detection, preamplifier (2), weighting network (4), level detector (6), and alarm mechanism (8). This device is battery operated and can be easily clipped on a belt so as to be worn by pregnant women at the abdominal level to monitor SPL at the abdomen. SPLs are measured in the range of greater than 80 dB and less than 100 dB over a frequency range of greater than 30 Hz and less than 10,000 Hz. The mother is alerted to SPLs that are exceeding a predetermined level to protect the hearing of the mother's developing fetus by a visual and/or a mechanical alarm. A distinguishing feature of the invention is the weighting network which enhances low frequency SPLs (greater than 30 Hz and less than 1000 Hz) by greater than 5 dB and less than 15 dB and attenuates high frequency SPLs (greater than 1000 Hz). In a preferred embodiment, an alarm signal will be presented to the user of the device when sound pressure levels in the vicinity of the user are greater than 80 dB at frequencies between greater than 30 Hz and less than 1000 Hz, with gradually increasing SPLs required with higher frequency such that 100 dB SPL is required to produce an alarm at greater than 4000 Hz and less than 5000 Hz.