John Bench

A Comparison between the Neonatal Sound‐evoked Startle Response and the Head‐drop (Moro) Reflex

Twelve clinically normal neonates were exposed to the stimuli of head‐drop (D) and to 96 dB spl (startle‐inducing) sound (S). Their behaviour was recorded on videotapes and viewed by eight experienced observers, according to three different sets of instructions.

Hyper‐responsivity to Sounds in the Short‐gestation Baby

Two experiments were devised in which the auditory responses and spontaneous ‘responses’ of short‐gestation babies were compared with full‐term infants in two prestimulus arousal states. In both states (‘light sleep’ and ‘deep sleep’) the full‐term babies tended to be the better sound detectors (significant at the 5 per cent level in light sleep; just failed 5 per cent level in deep sleep). A hyper‐reaction to sounds by the short‐gestation babies in a state of light sleep appeared to be associated with a higher level of spontaneous activity. This hyper‐reaction was interpreted as evidence of hyper‐responsivity rather than hyper‐sensitivity.

Studies in Infant Behavioural Audiometry: I. Neonates

The behaviour of 93 clinically normal neonates was video-recorded while they were presented with sequences of sound stimuli which varied in sound pressure level, bandwidth and rise time and which 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 sec at each trial. The first 5 sec was a pre-stimulus observation period, and the second 5 sec usually contained a sound stimulus. Between the trials, the observers were given 20 sec in which to record (1) pre-stimulus activity, (2) confidence in response, and (3) movement details (data for (3) not reported here). For the whole-body aspect, observers were allowed to see (1) the whole body, (2) the head, arms and trunk, (3) the arms, trunk and legs, (4) the head only, (5) the arms and trunk only, or (6) the legs only, during different viewing sessions. For the head aspect, they could see (7) the whole head, (8) the head above the upper lip, or (9) the head below the upper lip. This segmentation was achieved by masking parts of the television screen with shutters. 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 (p less than 0.001), bandwidths (p less than 0.001), and rise times (p less than 0.01). There were significant interactions between sound pressure level X bandwidth (p less than 0.001), sound pressure level X rise time (p less than 0.01), and bandwidth X rise time (p less than 0.001). A 90-dB broad-spectrum noiseband was by far the most effective stimulus. The response to different sound stimuli was differentially affected by pre-stimulus activity state. The results are discussed in relation to recent work on clinical screening techniques.

Summarizing Pure Tone Audiograms: An Extension of Bamford et al. (1980)

This paper extends the findings of a previous report (Bamford et al., 1980) which described a principal components analysis of pure tone audiometric data. Using a similar approach to the analysis of a large number of pure tone audiograms, the present study confirms the previous work. By far the greater part of the the audiogram variance could be ascribed to two components, one associated with the degree of, and the other with the slope of, the hearing loss. Further, it is shown that the proportions of the variance attributed to the two components change in a meaningful way according to the type of hearing loss: middle-ear, inner-ear, and mixed.

Neonatal auditory habituation and state change

Groups of newborn babies were exposed to various series of 90 dB SPL noiseband stimuli or to simulated (control) stimuli, while their heart rates (HR) and states of behavioural arousal were monitored. In general the response to stimulation was an accelerative HR change which tended to decrease with repeated stimulation. This seemed to provide evidence of habituation to the auditory stimuli. However, the HR response to sound depended on prestimulus HR and on state, and, when these effects were removed by regression techniques, the progressive decrease in evoked HR with repeated stimulation disappeared, apart from the first few trials. This implied that there was HR habituation to the initial stimuli, but not subsequently, when the apparent HR “habituation” reflected progressive endogenous state changes.

Auditory Deprivation-An Intrinsic Or Extrinsic Problem? Some Comments on Kyle (1978)

The relevance of animal work to early auditory deprivation, as discussed by Kyle (1978), is questioned. It is argued that auditory experience from birth, or even much later, is not necessarily required for subsequent hearing for spoken language. It is also questioned whether concern for intrinsic difficulties, such as possible cortical damage resulting from auditory deprivation, is appropriate. A more productive approach may be to pay more attention to the extrinsic aspect--the linguistically principled rehabilitation of the hearing-impaired child.

“Square-wave stimuli” and neonatal auditory behavior: Some comments on Ashton (1971), Hutt et al. (1968) and Lenard et al. (1969)

Abstract Recent work reporting neonatal auditory responses to complex tones generated by applying electrical square-wave stimuli to loudspeakers is reviewed with reference to the nature of the acoustic stimulus. Attention is particularly drawn to the harmonic structure of such tones in relation to the nonlinear frequency response of small loudspeakers. A 1 3 - octave band analysis of some “square-wave tones” is given to illustrate the difficulties of interpreting the results of work using such complex stimuli. The findings of the previous studies are ascribed essentially to differences in the stimulus bandwidth, rather than to differences in audiofrequency, and difficulties apparently generated by using differences in stimulus bandwidth as the sole explanation are at least partially resolved.

Audio-Frequency and Audio-Intensity Discrimination in the Human Neonate

Two experiments were performed on newborn babies; one on audio-frequency and the other on audio-intensity discrimination. The technique was to stimulate the babies with sounds until they ceased to respond according to a criterion. Then the appropriate acoustic variable was changed and the response reappeared. The results suggest that the audio-frequency discrimination was not due to fatigue in the sensory end organ but rather to some central process. Additionally, individual differences in discriminative capacity are considered.ResumeDes nouveaux nes ont ete soumis a deux experiences; Iune sur la discrimination des frequences auditives, Iautre sur la discrimination des variations dintensite tonale. On a presente un ton comme stimulus, jusquau moment oil les bebes ont cesse de repondre. Ensuite, le signal acoustique variable a ete change et la reponse a reapparu.Les resultats suggerent que la discrimination des frequences auditives nest pas la consequence de la fatigue auditive au niveau de la cochlee...

Paedo-Audiqlogy: Stalled at the Crossroads

Given that Paedo-Audiology should have a scientific basis, the author argues that (1) Science proceeds by establishing a consensus and, as a Science, a consensus should be established for Paedo-Audiology; (2) the subjective (direct observation) audiological tests for young and ‘difficult to test’ children do not at present permit a true consensus, because there is little rational basis for choosing between subjective test methods and test dimensions; and thus (3) the situation presents an impasse. He suggests that the arbitrary and subjective nature of direct observation does not present difficulties of itself. Rather, the problem concerns a lack of agreement as to precisely which techniques and units of measurement should be used. At present there seems to be no way of resolving this lack of agreement.This does not necessarily imply that subjective Paedo-audiological assessments as presently conducted in the clinic are unsound, but it does mean that an exact and well structured Science of subjective Paed...

Stimulus Complexity, State and Infants' Auditory Behavioural Responses

SummaryFor some time it has been known that “complex” sound stimuli are more effective than pure tones in eliciting behavioural and other responses from infants aged 0-6 months. We have recently studied this issue in some detail, and confirm that stimulus complexity defined in terms of frequency bandwidth is of major importance in eliciting behavioural responses from infants aged 1 week, 6 weeks and 6 months. We have also found that the human voice is effective for 6 month oldinfants but apparently not for babies aged 1 and 6 weeks. These findings are modified by the babys state of wakefulness, the effects of which are also considered. Comments are made on the implications of our data for clinical audiological assessments.