Graeme Clark Collection

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1994 - 1995 3
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Author: COHEN, LAWRENCE × Author: Rickards, Field × Subject: deafness ×

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    The automated prediction of hearing thresholds in sleeping subjects using auditory steady-state evoked potentials
    RANCE, GARY ; Rickards, Field W. ; Cohen, Lawrence T. ; De Vidi, Sandra ; Clark, Graeme M. ( 1995)
    Objective: To examine the relationship between auditory steady-state evoked potentials (SSEPs) and behavioral thresholds in sleeping subjects. Design: 60 adults and children with hearing thresholds ranging from normal to profound were selected on the basis of appropriate audiograms. Behavioral audiograms were determined at the octave frequencies 250-4000 Hz. These behavioral thresholds were then compared with the SSEP thresholds obtained during natural sleep for adults, or natural or sedated sleep for children. Results: A strong relationship between behavioural and SSEP thresholds was observed. The strength of the relationship increased with increasing frequency and increasing degree of the loss. On the basis of these data, the prediction of behavioural thresholds from SSEP levels was determined. It was found that the standard deviation of the error in this prediction decreased with increasing frequency and increasing degree of the loss. There was no significant age effect in the results obtained at any of the frequencies. Conclusion: The results suggest that the SSEP technique can be used as a predictor of behavioural thresholds in adults and children at the frequencies 250-4000 Hz.
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    Accuracy of behavioural threshold prediction using steady-state evoked potentials [Abstract]
    RANCE, GARY ; RICKARDS, FIELD ; Cohen, Laurie ; Clark, Graeme M. ( 1994)
    This paper examines the confidence with which predictions of hearing level can be made using the steady-state evoked potential (SSEP) technique. Steady-state evoked potentials are scalp potentials that can be elicited in response to sinusoidally amplitude and/or frequency modulated tones in sleeping or awake subjects. SSEP thresholds were obtained using frequency specific stimuli at octave frequencies between 250Hz and 4000Hz in 25 children and 35 adults with varying degrees of sensori-neural hearing loss. These levels, determined automatically by a computerised detection system, were then compared with thresholds obtained behaviourally. Linear regression analyses of this data have shown that the SSEP procedure allows objective estimates of hearing level to be made for a range of carrier frequencies to within 10dB accuracy on 96% of occasions.
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    The diagnostic assessment of infants using steady-state evoked potentials [Abstract]
    RANCE, GARY ; RICKARDS, FIELD ; Beer, David ; Cohen, Laurie ; Clark, Graeme M. ( 1994)
    This paper examines the relationship between the steady-state potential and behavioural thresholds obtained in two groups of young children. The first group consists of 10 babies referred to the Victorian Children's Hearing Centre following abnormal findings on screening ABR assessments. The second group contains 20 difficult to test infants who had unconfirmed hearing losses at the time of the SSEP assessment. The hearing levels predicted by the regression lines (described in the companion paper presented at this conference) were in close agreement with the behavioural levels obtained subsequently from children in both groups.