A precursor of language acquisition in young infants.

From general to language-specific capacities: the WRAPSA Model of how speech perception develops

Fetal sensory competencies

By sucking on a nonnutritive nipple in the presence of one discriminative stimulus, newborns were reinforced with a low-pass filtered tape recording of their mothers' voices. Sucking in the presence of a different discriminative stimulus was reinforced with unfiltered maternal-voice recordings. Filtered versions simulated maternal-voice sounds that were available before birth and unfiltered versions simulated maternal-voice sounds available after birth. Newborns in the control group could be reinforced with the same stimuli in the same way, but the voices were unfamiliar to them. Infants hearing their mothers' voices had no preference for either version, but infants hearing the unfamiliar voices preferred the unfiltered version. The difference in the between-groups responsiveness to the low-pass voice samples is consistent with the hypothesis that prenatal experience with low-frequency characteristics of maternal voices influences early postnatal perception of maternal voices.

Prenatal experience with low-frequency maternal-voice sounds influence neonatal perception of maternal voice samples

To review the existing evidence used to identify potentially better care practices that support newborn brain development. Literature review. Sixteen potentially better practices are identified and grouped into two operational clinical bundles based upon timing for recommended implementation. Existing evidence supports the implementation of selected care practices that potentially may support newborn brain development.

The development of potentially better practices to support the neurodevelopment of infants in the NICU

The sound environment of the foetal lamb was recorded using a hydrophone implanted a few weeks before term in a small number of pregnant ewes. It was implanted inside the amniotic sac and sutured loosely to the foetal neck, to move with the foetus. Results differ from those reported earlier for the human foetus: sounds from the maternal cardiovascular system were picked up only rarely, at very low frequencies and at sound pressures around, or below, the human auditory threshold. Other sounds from within the mother occurred intermittently and rose to a high sound pressure only at frequencies above about 300 Hz. Sounds from outside the mother were picked up by the implanted hydrophone when the external sound level rose above 65-70 dB SPL, and the attenuation in sound pressure was rarely more than 30 dB and, especially at low frequencies, usually much less. However, attenuation due to the transmission of sound through the body wall and other tissues tended to change from time to time. It is concluded that the foetal lamb's sound environment consists of (1) intermittent low frequency sounds associated largely with the ewe's feeding and digestive processes and (2) sounds such as vocalisations from the flock, human voices and other sounds from outside the mother.

J. Toner

Papers

The Sound Environment of the Foetal Sheep