Sound transmission to the human foetus through the maternal abdominal wall.
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Abdominal Muscles↗
Biomedical subjects
J Bench
Publications and source records attributed to J Bench.
Some effects of prestimulus activity and length of prestimulus observation on judgments of newborns' responses to sounds.
Previous work on the effects of prestimulus state on newborn auditory response is briefly reviewed. Subjectively assessed responses of nine newborns by five observers were studied as a function of (1) prestimulus activity level and (2) duration of prestimulus observation period. Response assessment was significantly affected for the former but not by the latter. For sounds which elicited a high proportion of responses, the prestimulus activity level had relatively little effect on judgment of response, whereas for sounds (and no-sound "control" trials) to which few responses were ascribed, prestimulus activity tended to be associated with positive ratings of response.
Acoustic Stimulation↗
Some effects of prestimulus activity and length of prestimulus observation judgements of infants' auditory behaviour.
The auditory responses of nine 6-week-old and ten 6-month-old infants were assessed subjectively by a group of four observers. These responses were evaluated as a function of (1) prestimulus activity level and (2) duration of prestimulus observation. Response assessment for both ages was significantly affected by the first but not by the second. The percentage of responses for both ages tended to decrease with increasing prestimulus activity state. The findings are compared with the similar study of Langford et al. [1974] on neonates.
Acoustic Stimulation↗
Studies in infant behavioural audiometry. II. Six-week-old infants.
The behaviour of 90 clinically normal 6-week-old babies previously studied as neonates was video-recorded while they were presented with sequences of sound stimuli. The stimuli varied in sound pressure level, bandwidth and rise time, and included two voice signals and a no-sound (control) trial. Video records were made both for the whole body aspect and for a 3 1/2 X 'close-up' of the head. Later, the video records were shown to 6 observers who were allowed to see the babies for 10 s at each trial. The first 5 s was a prestimulus observation period, and the second 5 s usually contained a sound stimulus. Between the trials, the observers were given 20 s in which to record (i) prestimulus activity, (ii) confidence in response, and (iii) movement details (data for [iii] not reported here). Different segments of the baby's body were observed on different occasions as detailed in our neonatal report. The response confidence ratings were analysed, using aspects of signal detection theory, to show differences amongst various body segments (p less than 0.001), sound pressure levels (SPL) (p less than 0.001), band widths (BW) (p less than 0.001), and rise times (RT) (p less than 0.001). There were significant interactions between SPL and BW (p less than 0.05) and SPL X RT (p less than 0.001). The 3 factor interaction (SPL X BW X RT) was also significant (p less than 0.001). A 90-dB broad-spectrum noise band was by far the most effective stimulus. The response to different sound stimuli was affected by the baby's posture (lying or sitting) and by prestimulus activity state. The results are discussed in relation to our previous neonatal study.
Acoustic Stimulation↗
Studies in infant behavioural audiometry. III. Six-month-old infants.
The behaviour of 95 clinically normal 6-month-old babies previously studied as neonates and as 6-week-old infants was video-recorded while they were presented with sound stimuli. The stimulus series varied in sound pressure level (SPL) (30 and 60 dB), band with (BW) and rise time (RT), and included two voice signals and a no-sound (control) trial. Video-records were made both for the whole body aspect and for a 3 1/2 X 'close-up' of the head. Later, the video-records were shown to 6 observers who were allowed to see the babies for 13 s at each trial. The first 5 s was a pre-stimulus observation period, and the second 8 s usually contained a sound stimulus. Between the trials, the observers were given 20 s in which to record pre-stimulus activity, confidence in response, and movement details. Data for movement details are not reported here. Different segments of the baby's body were observed on different occasions as detailed in our previous reports. The confidence ratings for response to tonal stimuli were analyzed using aspects of signal detection theory for differences amongst various body segments (n.s.), SPL (p less than 0.001), BW (p less than 0.05), and RT (p less than 0.01). A 60-dB broad-spectrum noise band (BSN) and the 2 voices were by far the most effective stimuli. They elicited detectablities which differed between segments. The response to different sound stimuli was affected by the baby's pre-stimulus activity state. The results are discussed in relation to our previous studies.
Acoustic Stimulation↗