The Role of Early Auditory Development in Attachment and Communication
Section snippets
Fetal audition
After decades of research with fetuses of different species, including humans, and with newborn preterm infants, it is clear that humans are capable of hearing a variety of sounds for about 3 months before birth. For a thorough recent review of fetal and neonatal auditory development, see Granier-Deferre and colleagues.4
The cochlea is functional by around 24 weeks’ gestational age (GA),5 and an ultrasound study showed that, by 27 weeks, 96% of fetuses responded with movement to loud (up to 120
Development of attachment
The emotional attachment of the infant to his or her mother has potential precursors in the intrauterine experience of sounds associated with mother, such as her talking, her laughter, her songs, and her heartbeats. Intrauterine recordings show that the maternal voice has a privileged status among voice sounds, if not in clarity, then in intensity,3, 35 total amount of exposure, and likely in a route that has sensory redundancy. Each occurrence of maternal voicing is accompanied by perfectly
Language development
If the early development of audition is likely to play a key role in socioemotional attachment, it most certainly plays one in communication for most people. The major mode of human communication is language, and, for all but a minority of people, language is oral/aural. There are indications that most elements of the speech signal are available to the fetus, at least intermittently. Intrauterine audio recordings made during labor after rupture of membranes in humans35 and in fetal lamb cochlea
Sensitive periods
A notable aspect of both attachment and language acquisition is that they are experience-dependent and that there are sensitive or critical periods for both. As studies of institutionalized children have shown, early isolation increases the risk of subsequent poor attachment and mental health despite a later opportunity to form an emotional bond with a caregiver.42 Similarly, children who have not been exposed to speech by early childhood are not likely to acquire completely normal use of
Excessive sound
Excessive noise damages the auditory system, particularly the hair cells of the cochlea, but little research has been done on the effect of prenatal exposure to excessive noise. Controlled exposure of fetal sheep to loud noise increased postnatal auditory brainstem response thresholds, and resulted in damage to cochlear hair cells.48 In humans, retrospective studies have shown that women who experienced loud occupational noise while pregnant had children with increased risk for hearing loss.49,
Deafness
Many other factors besides excessive prenatal noise can compromise the early development of the auditory system. Approximately 2 to 3 in 1000 infants are born deaf or hard of hearing, 90% of whom are born to parents who can hear.54 Infants who have little or no prenatal or early postnatal exposure to auditory stimulation are test cases for the importance of audition to the development of attachment and communication, especially spoken language. The research literature on deafness and language
Hospitalized preterm infants
Hospitalized preterm infants have neither excessive nor impoverished auditory experience during early development, but their experience is markedly different from what is typical for late-term gestation. These infants’ early development occurs in medical settings in which guidelines regarding excessive sound have been implemented, and sound levels are controlled.60, 61 Even in environments in which loud, percussive sound has been eliminated, the spectral and temporal composition of sound is not
Function of prenatal auditory experience and plasticity
The evidence reviewed earlier shows that the late-term fetus typically has had abundant experience with sounds of the social environment, and that important bases for attachment and language are present at birth. There also is evidence that individuals without such bases at birth nevertheless establish healthy attachments with caregivers and acquire spoken language. It is reasonable to ask what functions fetal auditory perception and learning serve if not preparation for vital postnatal
Fetal stimulation programs
If late-term fetuses are able to detect, perceive, and take action (eg, by directing their attention) when stimulated with sound, then the question arises as to whether it is possible or desirable to educate the unborn child. It is clear that it is possible. The late-term fetus retains the experience of a melody for up to a month after birth.23 Is it desirable? From the perspective of the parents’ or siblings’ attachment to the infant who will shortly arrive, it could be part of a healthy
Summary
Several conclusions can be drawn from studies of perinatal auditory development. There is no doubt that auditory perception and learning take place for most typically developing fetuses. Sounds of social life are prominent in the intrauterine environment, and they provide opportunities for prenatal learning about eventual attachment figures and language(s). Typical development includes prenatal learning about ambient social sounds, but fetuses and newborns who lack the typical auditory exposure
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Cited by (20)
Neuroprotective Core Measure 1: The Healing NICU Environment
2015, Newborn and Infant Nursing ReviewsCitation Excerpt :The word noise comes from nausea, the Latin word for sickness. Excessive noise levels in the NICU can damage the developing cochlea and delicate auditory structures, especially the hair cells of the cochlea, ultimately resulting in hearing loss.65 A more immediate effect of noise is arousal and disruption of normal sleep cycles, which are detrimental to the developing neonate in many ways.23
Sensory Development
2015, Pediatric Clinics of North AmericaCitation Excerpt :With progressive or new-onset hearing loss, the prevalence of permanent sensorineural hearing loss increases during childhood to estimated rates of about 2.7 per 1000 in 4-year-old children and 3.5 per 1000 in adolescents.10,14 Based on the anatomic location of the hearing dysfunction, hearing loss can be classified as conductive, sensorineural, or neural15–19: Conductive hearing loss: blockage of sound transmission in the outer or middle ear caused by permanent conditions like anatomic malformations or transient problems such as fluid or debris.
The Neonatal Integrative Developmental Care Model: Seven Neuroprotective Core Measures for Family-Centered Developmental Care
2013, Newborn and Infant Nursing ReviewsCitation Excerpt :The word noise comes from nausea, the Latin word for sickness. Excessive noise levels in the NICU can damage the developing cochlea and delicate auditory structures, especially the hair cells of the cochlea, ultimately resulting in hearing loss.66 A more immediate effect of noise is arousal and disruption of normal sleep cycles, which are detrimental to the developing neonate in many ways.47
Automated cortical auditory evoked potentials threshold estimation in neonates
2019, Brazilian Journal of OtorhinolaryngologyCitation Excerpt :It is through hearing that a child can experience the world of sound, promoting the development of spoken language. The anatomical and functional integrity of the peripheral and central auditory system, together with exposure to auditory experiences, are basic requisites for the normal acquisition and development of language.1 Thus, assuring reliable estimates of auditory thresholds in the infants is paramount.
Early Neonatal Intervention: A Newer Conceptual Paradigm
2022, Journal of Neonatology
Financial disclosure/conflicts of interest: the author has nothing to disclose.
Funding provided by National Institutes of Health Grant HD 37954 to Patricia K. Kuhl, University of Washington, Seattle, USA.