Do fetuses move their lips to the sound that they hear? An observational feasibility study on auditory stimulation in the womb

Abstract

BackgroundWe investigate in this feasibility study whether specific lip movements increase prenatally when hearing a particular sound. We hypothesised that fetuses would produce more mouth movements resembling those required to make the sound stimulus they heard (i.e. mouth stretch) compared with a no-sound control group who heard no specific auditory stimuli. Secondly, we predicted that fetuses hearing the sound would produce a similar number of mouth movements unrelated to the sound heard (i.e. lip pucker) as the no-sound group of fetuses.MethodsIn an observational feasibility study, 17 fetuses were scanned twice at 32 and 36 weeks of gestation, and two different types of mouth movements were recorded. Three fetuses received an auditory stimulus, and 14 did not. A generalised mixed effects log-linear model was used to determine statistical significance.ResultsFetuses in the sound group performed one specific mouth movement (mouth stretch) significantly more frequently than fetuses in the no-sound group. A significant interaction between group and gestational age indicates that there was differential change in this specific movement as age increases (X 2 = 7.58 on 1 df, p = 0.006), with the no-sound group showing a decline of 76 % between 32 weeks and 36 weeks (p < 0.001), whereas the sound group showed no significant change over time (p = 0.41). There was no significant difference between the sound group and no-sound group in the frequency of lip puckering—the second, unrelated mouth movement (p = 0.35).ConclusionsThese results suggest that a sound stimulus is associated with an increase in specific, rather than general, mouth movements. The results are informative for the development of infant speech and potentially could also lead to a diagnostic test for deafness in utero. More research is needed to replicate this research with a randomised design and with a range of different auditory stimuli which would be produced with different mouth movements, such as “o” which would be seen as pursed lips.Electronic supplementary materialThe online version of this article (doi:10.1186/s40814-016-0053-3) contains supplementary material, which is available to authorized users.

Effects of maternal anxiety and depression on fetal neuro-development

“…All sounds were played through a Sansa Clip portable MP3 device connected to a Anker portable speaker at frequencies between 0Hz and 11kHz, with most outputs at 0.6-1.6kHz and 2.6-3kHz regions. These frequencies are audible to fetuses from 29 weeks gestation (Gerhardt & Abrams, 2000;Reissland, et. al., 2016a) but produce a safe level of sound which will not harm fetal hearing (Krueger, Horesh & Crossland, 2012).…”

“…Running title: fetal blinking, maternal anxiety & depression 12 conditions and from fetus to fetus. Here, therefore, a mixed effects Poisson log-linear model was fitted (see Reissland, Francis & Mason, 2012;Reissland, Francis, Aydin, Mason & Schaal, 2014;Reissland et. al., 2016a), using number of eye-blinks as the dependent variable with an offset of log codable scan length (thus modelling eye blink rate) and with explanatory variables of sound type, light presence, experimental condition order (assessing habituation), light intensity at the fetus, gender of fetus, and depression, anxiety and stress, and with a random effect assessing between fetus variability.…”

A description of externally recorded womb sounds in human subjects during gestation

“…for sound localization in mammals generally, and for speech perception in humans in particular. [ 25 ] Previous research has shown the acquisition of speech perception begins in fetal life,[ 26 ] and that disruptions in normal fetal development (ie. intra-uterine growth restriction of a fetus) can negatively influence language development.…”

Fetal Origin of Sensorimotor Behavior

“…; Ferrari et al, 2016 ). In a similar study, fetuses reacted with a specific configuration of mouth opening to hearing the sound “ma” being repeated (Reissland et al, 2016 ). Finally, in another study which has still to be replicated, 25-week-old fetuses were more likely to engage with upright face-like visual stimulus presented through the uterus than with inverted ones 3 (Reid et al, 2017 ).…”