Transmission Loss of Sound Into Incubators: Implications for Voice Perception by Infants
Objective: To assess the transmission of sound into incubators as a function of talker position (i.e., standing or sitting), incubator port position (i.e., opened or closed), and center frequency (i.e., 125 to 10,000 Hz in one-third octave steps). The second objective was to estimate the audibility of the human voice inside the incubator.
Study Design: Leq measures of signal transmission loss and motor noise were obtained from two incubators.
Results: In general, signal transmission loss was greater for the standing-talker position, with front portholes closed, and for high-frequency spectra. Motor noise was greater with both front portholes closed and for lower-frequency spectra. The greatest signal delivery to an infant would be obtained when the speaker is sitting using a raised vocal effort while the incubator ports are opened.
Conclusion: Measured signal transmission loss and motor noise characteristics of two incubators suggest that only mid-frequency speech spectra would be audible to infants and only at a speech-to-noise ratio of approximately 5 to 10 dB with a raised vocal effort.
Communication Sciences and Disorders
Robertson, Alex, Andrew Stuart, and Letitia Walker. "Transmission loss of sound into incubators: Implications for voice perception by infants." Journal of Perinatology 21, no. 4 (2001): 236-241.