Studies in Hearing Development in Newborns

Before the baby is born the baby inside his mother's womb hears. Researchers now agree that the baby perceives sounds between the fifth and eighth month. From that point onwards the child can become a music lover, a step that will be taken soon!

At seven months of development in the uterus, the foetus hears sounds and noises. The foetus then responds by moving to external sound stimuli when they are intense enough to cover the noise associated with cardiovascular and digestive activities of the mother.

Hearing memory

These auditory sensations are transmitted only by means of bone conduction because the ducts are clogged with wax. It seems that these sounds are saved in the child's memory. During the last six months of their pregnancy, women read aloud to children several times a day. After birth, the young listeners mark text preferences even when read by another reader besides their mother. Similar experiments have used readings, songs or music variety. John Feijoo highlighted the packaging of the foetus by the sounds from the 5th month of pregnancy (with the example of air bassoon Peter and the Wolf, which symbolizes the grandfather, whose notes have a frequency of less than 1000 hertz). Beyond the confirmation of the prenatal hearing, these experiments lend themselves to staggering mnemonic capabilities to the baby. For some researchers, the foetus begins learning to speak at the 7th month of intrauterine life.

Preference for bass sounds

From birth, the newborn detects the presence of noise, directs his head and his eyes in their direction and is able to discriminate some of their properties. He is very sensitive to rhythmic and melodic characteristics of sound sequences. The child is more stimulated by bass sounds rather than high-pitched sounds.

For Decasper and Fifer, infants less than three days distinguish the voice of their mother in a foreign female voice. According to Jacques Mehler, the newborn recognizes the voice of his mother at the end of the first month. For White, the ability to identify the voice of his mother among other women occurs at around 4 or 5 months.

Most of the babies hear better when they are quiet but while awake they do not cry or breastfeed. In case of noise, the newborn blink his eyes, cries and holds his breath. If a toy is shaken in the dark, the newborn points with his hands in the right direction. This behaviour disappears after a few months. Initially, the view seems secondary since between two stimuli, one visual, and the other sound, the baby turns his gaze to the latter. At around 9 months, the opposite happens.

At around 3 or 4 months, the infant turns his head towards the noise source. At 32 weeks, he answers to the call of his name. At 36 weeks, he mimics the sounds produced by his mother. Children being 9 to 12 months old will start to understand the meaning of several words.

Medically, the hearing of newborns may be tested in case of doubt, by looking for oto-emissions. If necessary, an electroencephalogram (EEG) or an electromyography (EMG) can be practiced.

Sources:

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