Graeme Clark Collection
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ItemThe automated prediction of hearing thresholds in sleeping subjects using auditory steady-state evoked potentials( 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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ItemAccuracy of behavioural threshold prediction using steady-state evoked potentials [Abstract]( 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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ItemThe diagnostic assessment of infants using steady-state evoked potentials [Abstract]( 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.
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ItemSteady state evoked potentials: a new tool for the accurate assessment of hearing in cochlear implant candidates( 1993)Precise determination of residual hearing in prospective cochlear implant candidates is essential. As the minimum age of implantation for young children has reduced, the use of objective measures of hearing has become more important. At the University of Melbourne Cochlear Implant Clinic, steady state evoked potential (SSEP) assessments are routinely carried out on all candidates under the age of 5 years using a microcomputer and custom-designed hardware in the manner described by Cohen et al. [1].
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ItemA comparison of steady-state evoked potentials to modulated tones in awake and sleeping humans( 1991)Abstract not available due to copyright.
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ItemSteady state evoked potentials (SSEPs): An objective measure of residual hearing in young cochlear imlpant candidates( 1993)The use of objective measures of residual hearing in young cochlear implant candidates has become more important as the minimum age of implantation has reduced. This paper examines the use of the steady-state evoked potential (SSEP) technique in the assessment of these children. SSEP thresholds were obtained using frequency specific stimuli at octave frequencies between 250llz and 4000Hz in ZS children with moderate to severe hearing losses. These levels, determined automatically by a computerized detection system were then compared with thresholds obtained behaviourally. Data was also collected from a group of 35 adult subjects with varying degrees of sensorineural hearing loss. Results indicate that the steady-state evoked potential procedure can provide accurate, frequency specific estimates of hearing thresholds in ears with even profound or total hearing losses.
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ItemSteady state evoked potentials: an objective measure of residual hearing in young cochlear implant candidates [Abstract]( 1993)Precise determination of hearing thresholds in prospective cochlear implant candidates is essential. As the minimum age of implantation for youl1g children has been reduced, the use of objective measures of hearing has become an important part of their pre-operative evaluation. Steady-state evoked potentials are scalp potentials elicited in response to sinusoidally amplitude and/or frequency modulated tones. A system has been developed at The University of Melbourne which allows the presence: of such a response to be detected automatically thus permitting an objective. frequency specific estimate of hearing to be made in sleeping or awake subjects. This paper investigates the use of SSEPs in determining hearing thresholds in young profoundly deaf children. Responses in such patients are compared with those: obtained in neonates, and a group of sleeping adult subjects with varying degrees of sensori-neural hearing loss. Results indicate that the SSE? procedure is well suited as a measure assessing residual hearing in profoundly deaf children suitable for a cochlear implant in that it can provide an accurate estimate of auditory thresholds using frequency specific stimuli presented at high levels.
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ItemSteady-state evoked potentials (SSEPS): an accurate, automated, frequency specific method for objectively assessing hearing thresholds [Abstract]( 1992)The determination of hearing thresholds in young children and some adults is impossible using conventional behavioural audiometry. The development of objective methods of assessment for use in such patients is highly desirable.
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ItemSteady-state evoked potentials (SSEPS): a new tool for the accurate assessment of hearing in cochlear implant candidates [Abstract]( 1992)Determining hearing thresholds is crucial in assessing cochlear implant candidates; never more so than in young children unable to undergo behavioural audiometry. In these children an objective measure of hearing is desirable. Steady-state evoked potentials (SSEPs) are potentials recorded from the scalp and simultaneously analysed. Stimuli ore amplitude and frequency modulated pure tones. A system has been developed which allows the presence of such a response to be automatically detected and the technique thus permits an objective, frequent specific assessment of hearing threshold to be mode in sleeping or awake subjects (1). This paper investigates the use of SSEPs in determining hearing thresholds in young profoundly deaf children who are candidates for cochlear implants. Responses in such patients are compared with those obtained in normal adults, neonates and experimental animals. Results indicate that the SSE? can provide a consistent and reliable measure of threshold and the technique appears to have a number of advantages over the auditory brainstem response: automated response detection removes the subjective element of threshold determination, higher levels of stimulus presentation are possible, low frequency threshold determination is more accurate and the testing procedure IS quicker.