The Sound Environment of the Foetal Sheep

Baldwin, B.A.; Moore, Brian C. J.; Armitage, Sally E.; Toner, J.N.; Vince, Margaret A.

doi:10.1163/156853982x00184

Cited by 39 publications

(8 citation statements)

References 5 publications

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“…The cardiac response to evidenced by elevated thresholds for fetal hearing [6] and potential damage to the fetal cochleae produced by noise trauma at vulner able periods during development [7], Highnoise levels are present in many jobs held by working pregnant women, yet the hearing conservation guidelines [8] neglect to mention potential risks for the fetus. The fetal acoustic environment has been studied extensively, and on the basis of both animal and human experiments [9][10][11][12][13][14][15] it has been found to be both rich and varied.…”

Section: Introductionmentioning

confidence: 99%

Vibroacoustic Stimulation with a Complex Signal: Effect on Behavioral State in Fetal Sheep

Abrams

Schwab²,

Gerhardt³

et al. 1996

Neonatology

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An ideal vibroacoustic stimulus for testing fetal reactivity has yet to be developed. In the present study in fetal sheep we tested the effect on behavioral state of an amplitude and frequency-modulated signal produced at the abdominal surface of the ewe. The stimulus was presented during periods of fetal non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. Evaluation of behavioral state was accomplished by visual observation of strip-chart recordings. Assessed in this manner, vibroacoustic stimulation during NREM sleep consistently resulted in a change to an indeterminate state. However, stimulation during REM sleep failed to have an effect. Additional evaluation applying spectral analysis to the fetal electrocorticogram during stimulation in NREM sleep revealed a marked decrease in delta band power from 100 to 27 ± 5% and in theta band power from 100 to 40 ± 4% resulting in a decrease in total power from 100 to 35 ± 4% (p < 0.05). Stimulation during REM sleep revealed a significant increase in beta band power from 100 to 123 ± 14%. Vibroacoustic stimulation in both NREM and REM sleep led to an increase in spectral edge frequency, implying central arousal.

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Section: Introductionmentioning

confidence: 99%

Vibroacoustic Stimulation with a Complex Signal: Effect on Behavioral State in Fetal Sheep

Abrams

Schwab²,

Gerhardt³

et al. 1996

Neonatology

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“…[314][315][316] Clinical observation suggests the fetus responds to sound as early as 20 to 26 weeks gestation. 316,317 The in utero environment of the growing fetus is exposed primarily to low frequency sound with filtering of high frequency noise, [318][319][320][321][322] with sounds above 500-1000 Hz attenuated by 20 to 50 dB. 320,322,323 Animal studies suggest that the hair cells of the developing cochlea are susceptible to damage by intense low frequency sounds.…”

Section: To 32 Weeks Gestational Age and Beyondmentioning

confidence: 99%

“…316,317 The in utero environment of the growing fetus is exposed primarily to low frequency sound with filtering of high frequency noise, [318][319][320][321][322] with sounds above 500-1000 Hz attenuated by 20 to 50 dB. 320,322,323 Animal studies suggest that the hair cells of the developing cochlea are susceptible to damage by intense low frequency sounds. [324][325][326] Premature delivery exposes the infant to both low and high frequency sound without the protective noise attenuation of the mother's body.…”

Section: To 32 Weeks Gestational Age and Beyondmentioning

confidence: 99%

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

et al. 2007

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

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“…Studies using a relevant animal model, the pregnant ewe, show heartbeat sounds as occasional features of a complex acoustic environment. 60,61 However, despite the failure to replicate the initial research and evidence weakening the underlying theory, a belief that heartbeat sounds are beneficial to babies persists in some clinical circles and in commercial enterprise.…”

Section: Heartbeat Soundsmentioning

confidence: 99%

Hearing and Behavioral Responses to Sound in Full-Term Newborns

Philbin

Klaas

2000

J Perinatol

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NEWBORN HEARING Behaviors Indicating Hearing in the Newborǹ`Can the baby hear this sound?''``Can he appreciate the difference between this sound and that one?''``Does she recognize my voice?''`I s that noise keeping him awake?'' These and similar questions are of interest to those caring for newborn infants and also to researchers. The answers to them depend in part on the baby behaviors that adults attend to because human newborns, despite their large brains and fairly well-developed hearing, are limited in what they can do to indicate they have heard something. Researchers have, therefore, devoted considerable effort to defining newborns' behavioral responses precisely and to developing measurements that all but eliminate unintentional bias from behavioral observations. Humans at birth have reasonably good control over the muscles that govern eye movement. With careful support they also have control over the muscles that turn the head. These abilities coupled with an apparently innate tendency to coordinate vision with hearing lead newborns to orient toward (turn eyes or head or both toward) new or preferred sounds if the sounds last 1 second or longer. 1Term newborns also have a reliable blink reflex that can be used to test hearing for fairly loud sounds. Newborn infants have good control over the muscles involved in sucking and tend to suck faster or harder in response to a new or interesting sound Ð or sight. Additionally, they can indicate their attention to a sound with a package of body movements and facial expressions that a parent or trained observer can learn to identify reliably. Researchers have catalogued some of the details of newborn hearing by making careful measurements of these naturally occurring movement responses to sound. The observant parent or clinician can also use these behaviors to try to understand an individual newborn's responses to the sounds in his or her environment.Unfortunately, however, newborns as individuals and as a group are very variable. Their periods of alertness can be brief, they pay attention differently at different times, and they are easily distracted. Their 4-to 8-second lag before responding and slow or uncoordinated head-turn movements can lend the impression of not responding, particularly if the sound signal is shorter than 1 to 2 seconds. 2After several repetitions of the same, moderately loud sound they may habituate to it (tune it out) and stop responding altogether. Infants at birth may show less sensitive hearing than a few days afterward if there is amniotic fluid in the middle ear although this drains away or is absorbed within 2 or 3 days. Of course, newborns' responses will be atypical if they are not well or are affected by medications or street drugs that the mother has transmitted before birth. Moreover, animal studies indicate that some aspects of hearing may develop very rapidly in the immediate period just after birth so that responses to a particular sound at time A may be quite different from responses to the same sound at time B only a sho...

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The Sound Environment of the Foetal Sheep

Cited by 39 publications

References 5 publications

Vibroacoustic Stimulation with a Complex Signal: Effect on Behavioral State in Fetal Sheep

Vibroacoustic Stimulation with a Complex Signal: Effect on Behavioral State in Fetal Sheep

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

Hearing and Behavioral Responses to Sound in Full-Term Newborns

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