Objective: The appropriate application of audiological measures during paediatric hearing aid (HA) fitting ensures the fitting is effective and provides speech audibility across the frequency range. Audiological assessment may include both behavioural and objective measures, such as auditory brainstem response (ABR) and auditory steady-state response (ASSR). ABR and ASSR measures however do not have a 1:1 correlation with behavioural measures, and correction values need to be applied to estimate behavioural thresholds prior to HA fitting. No study has previously described how South African audiologists are utilising ABR and ASSR results during paediatric HA fitting. This study aimed to describe the current South African audiological clinical practice for paediatric HA fitting, with specific reference to the application of ABR and ASSR measures. Design: The study employed a quantitative, non-experimental, descriptive, cross-sectional survey research design. Study sample: Thirty-four personal interviews with audiologists were completed, seven within the private health sector and 27 within the public health sector. Results: Results indicated that limited departmental protocols exist and adherence to available protocols was questioned. There was a lack of consensus regarding the application of correction values to ABR and ASSR measures for HA fitting and the values utilised often differed significantly from recommended guidelines. There appeared to be an over-reliance on electrophysiological measures for paediatric audiological assessment, as well as a lack of adherence to recommended age-appropriate assessment guidelines. Conclusion: Findings suggest the need for promoting improved clinical practice and knowledge within the area of paediatric audiology in South Africa. The need for the development of nationally-agreed guidelines was highlighted.

A utilização do Potencial Evocado Auditivo do Estado Estável na avaliação audiológica infantil tem ampliado, devido à possibilidade de estimulação binaural com tons puros de forte intensidade, além da análise objetiva da resposta. Diversos estudos têm sido realizados a fim de caracterizar a correlação da resposta eletrofisiológica com os limiares comportamentais, contudo, ainda não há um consenso quanto aos valores a serem utilizados para cada frequência pesquisada. Desta forma, o objetivo desse estudo foi correlacionar os limiares dos potenciais evocados auditivos de estado estável com os níveis mínimos de resposta obtidos na audiometria condicionada com reforço visual ou lúdica em crianças com perda auditiva neurossensorial de grau profundo a fim de determinar o fator de correção a ser utilizado na prática clínica. Foram avaliados 88 exames realizados em crianças na faixa etária de seis a 49 meses, totalizando 168 orelhas. Os resultados demonstraram correlação significante entre o limiar do Potencial Evocado Auditivo do Estado Estável e o nível mínimo de resposta apenas para as frequências de 500 e 1000 Hz, não sendo possível estimar o nível mínimo de resposta para as frequências de 2000 e 4000 Hz. Nas frequências de 2000 e 4000 Hz ocorreu presença de resposta eletrofisiológica em forte intensidade, mesmo na ausência de resposta comportamental. Os limiares do Potencial Evocado Auditivo do Estado Estável superestimaram o grau da perda auditiva considerando a classificação da perda auditiva profunda de acordo com Boothroyd (1997). / The use of Auditory Steady-State response in pediatric audiologic assessment has increased, owing to the possibility of binaural stimulation with strong intensity pure tones, besides the objective analysis of the response. Several studies have been carried out so as to correlate the electrophysiological response with behavioral thresholds, nevertheless, there is no consensus on the values to be used for each frequency investigated. Thus, this study aimed at correlating the thresholds of auditory steady-state response with the minimum response levels achieved in the ludic or visually reinforced audiometry in children presented with profound sensorineural hearing loss, in order to determine the correction factor to be used in clinical practice. Eighty-eight exams performed in children aged six to 49 months, totaling 168 ears, were assessed. The results showed a significant correlation between ASSR threshold and the minimum response level only for frequencies of 500 and 1,000 Hz, being impossible to rate the minimum response level for frequencies of 2,000 and 4,000 Hz which showed strong intensity electrophysiological response, even in the absence of behavioral thresholds. ASSR thresholds overestimated the degree of hearing loss, taking into account profound hearing loss rating, according to Boothroyd (1997).

Researchers previously have found a correlation between the strength of the auditory steady-state response (ASSR) and corresponding auditory behavioral measurements such as speech recognition scores, thus concluding that the ASSR can be used as an objective measurement of auditory supra-threshold properties. In the present study, it was hypothesized that the increase in the strength of the ASSR at different modulation depths would be reflected in corresponding psychophysical measures, specifically, auditory modulation discrimination. These relationships were investigated in normally-hearing listeners at modulation rates of 40 and 80 Hz for both amplitude (AM) and mixed modulation (MM), at several modulation depths. Analyses were completed for two sets of measurements derived from the physiological and behavioral responses. For the first analysis, derived measures of iso-neurometric thresholds were compared to isometric modulation discrimination thresholds. For the second analysis, derived estimates of physiological neurometric slope were compared to estimated psychometric function slopes. Mixed-model analyses for both of these measures revealed significant or near-significant relationships between physiological and psychophysical measures at 40 Hz for AM and at 80 Hz for MM. Bootstrap resampling analyses were completed to estimate the distribution of the resultant statistics. Implications regarding the location of neural encoding for amplitude and frequency modulation were discussed. / text

A utilização do Potencial Evocado Auditivo do Estado Estável na avaliação audiológica infantil tem ampliado, devido à possibilidade de estimulação binaural com tons puros de forte intensidade, além da análise objetiva da resposta. Diversos estudos têm sido realizados a fim de caracterizar a correlação da resposta eletrofisiológica com os limiares comportamentais, contudo, ainda não há um consenso quanto aos valores a serem utilizados para cada frequência pesquisada. Desta forma, o objetivo desse estudo foi correlacionar os limiares dos potenciais evocados auditivos de estado estável com os níveis mínimos de resposta obtidos na audiometria condicionada com reforço visual ou lúdica em crianças com perda auditiva neurossensorial de grau profundo a fim de determinar o fator de correção a ser utilizado na prática clínica. Foram avaliados 88 exames realizados em crianças na faixa etária de seis a 49 meses, totalizando 168 orelhas. Os resultados demonstraram correlação significante entre o limiar do Potencial Evocado Auditivo do Estado Estável e o nível mínimo de resposta apenas para as frequências de 500 e 1000 Hz, não sendo possível estimar o nível mínimo de resposta para as frequências de 2000 e 4000 Hz. Nas frequências de 2000 e 4000 Hz ocorreu presença de resposta eletrofisiológica em forte intensidade, mesmo na ausência de resposta comportamental. Os limiares do Potencial Evocado Auditivo do Estado Estável superestimaram o grau da perda auditiva considerando a classificação da perda auditiva profunda de acordo com Boothroyd (1997). / The use of Auditory Steady-State response in pediatric audiologic assessment has increased, owing to the possibility of binaural stimulation with strong intensity pure tones, besides the objective analysis of the response. Several studies have been carried out so as to correlate the electrophysiological response with behavioral thresholds, nevertheless, there is no consensus on the values to be used for each frequency investigated. Thus, this study aimed at correlating the thresholds of auditory steady-state response with the minimum response levels achieved in the ludic or visually reinforced audiometry in children presented with profound sensorineural hearing loss, in order to determine the correction factor to be used in clinical practice. Eighty-eight exams performed in children aged six to 49 months, totaling 168 ears, were assessed. The results showed a significant correlation between ASSR threshold and the minimum response level only for frequencies of 500 and 1,000 Hz, being impossible to rate the minimum response level for frequencies of 2,000 and 4,000 Hz which showed strong intensity electrophysiological response, even in the absence of behavioral thresholds. ASSR thresholds overestimated the degree of hearing loss, taking into account profound hearing loss rating, according to Boothroyd (1997).

No description available.

The Auditory Steady State Response (ASSR) procedure has been established as a frequency specific, objective audiologic measure, which can provide reliable thresholds to within 10 dB of the behavioral thresholds. In order for ASSR to find its place in the existing framework of audiometric procedures, the full potential of the procedure needs to be explored. The aim of this study was to determine the accuracy of monotic ASSR in estimating hearing thresholds in a group of 15 normal hearing subjects and 15 hearing-impaired subjects. A comparative research design was implemented. Indicating that results obtained in the study was compared to relevant literature where dichotic multiple ASSR was implemented. This was done in order to ascertain ASSR’s capabilities with regard to stimulus presentation methods. Monotic single ASSR predicted behavioural thresholds in the normal hearing subjects within an average of 24 dB across the frequency range (0.5, 1, 2&4 kHz). In the hearing-impaired group, ASSR thresholds more closely resembled behavioural thresholds, with an average difference of 18 dB, which is consistent with recent literature. The literature suggests that better prediction of behavioural thresholds will occur with greater degrees of hearing loss, due to recruitment. The focus in this group also centered on the accurate prediction of the configuration of the hearing loss. It was found that ASSR could reasonably accurately predict the configuration of the hearing loss. In the last instance, monotic single and dichotic multiple ASSR were compared with regard to threshold estimation and prediction of configuration of the hearing loss in the hearing-impaired group. Little difference was reported between the two techniques with regard to the estimation of thresholds in both the normal hearing and hearing impaired groups. In conclusion it was established that monotic ASSR could predict behavioural thresholds of varying degrees and configurations of hearing loss in normal and hearing-impaired subjects with a reasonable amount of accuracy. At this stage, however, more research is required to establish the clinical validity of the procedure, before it is routinely included within an objective test battery. / Dissertation (M (Communication Pathology))--University of Pretoria, 2005. / Speech-Language Pathology and Audiology / Unrestricted

Auditory Steady-State Response (ASSR) is a promising tool for detecting hearing loss. In this project, we analyzed hearing threshold data obtained from two ASSR methods and a gold standard, pure tone audiometry, applied to both normal and hearing-impaired subjects. We constructed a repeated measures linear model to identify factors that show significant differences in the mean response. The analysis shows that there are significant differences due to hearing status (normal or impaired) and ASSR method, and that there is a significant interaction between hearing status and test signal frequency. The second task of this project was to predict the PTA threshold (gold standard) from the ASSR-A and ASSR-B thresholds separately at each frequency, in order to measure how accurate the ASSR measurements are and to obtain a ¡°correction function¡± to correct the bias in the ASSR measurements. We used two approaches. In the first, we modeled the relation of the PTA responses to the ASSR values for the two hearing status groups as a mixture model and tried two prediction methods. The mixture modeling was successful, but the predictions gave disappointing results. A second approach, using logistic regression to predict group membership based on ASSR value and then using those predictions to obtain a predictor of the PTA value, gave successful results.

<p> </p><p>I denna studie har jämförelse gjorts mellan Interacoustics Eclipse och GSI Audera i samband med Auditory Steady-State Respons (ASSR) mätningar.</p><p>Syftet med studien var att undersöka ASSR som metod, att utvärdera dess tillförlitlighet i jämfö­relse med tonaudiometri för personer med normal hörsel och personer med hörsel­nedsätt­ning. Avsikten var dessutom att undersöka om elektrod­placering­ på örsnibb eller på mastoid påverkade mät­resultatet, försökspersonens upplevelse av instrumen­­t­ens ljudstimuli, om de estimerade ASSR-värdena påverkades av att mättillfället påbörjades eller avslutades med Interacoustics Eclipse samt undersöka tiden för mätningarna.</p><p>En experimentell studie genomfördes. Mätningarna som utfördes var tonaudiometri och ASSR, den senare uppmättes med Interacoustics Eclipse och GSI Audera på (n=20) vuxna med normal hörsel och (n=4) vuxna med hörselnedsättning.</p><p>För personer med normal hörsel påvisades en god överensstämmelse mellan estimerade ASSR-värden och tonaudiometri för Interacoustics Eclipse, något sämre överensstämmelse för GSI Audera. Genomsnittlig mättid för båda instrumenten var ca 40 min. Resultaten visade att elektrodplaceringen inte har någon påverkan på ASSR-värden för Interacoustics Eclipse. Hälften av försökspersonerna upplevde att Interacoustics Eclipse hade ett behagligare ljudstimuli att slappna av till och den andra hälften upplevde GSI Audera som behagligast. De estimerade ASSR-värdena påverkades minimalt beroende på om mättillfället påbörjades eller avslutades med Interacoustics Eclipse.</p><p> </p>

Individuals with high working memory capacity (WMC) appear to be particularly good at focusing their attention (McCabe, Roediger, McDaniel, Balota, &amp; Hambrick, 2010). Therefore, we studied the correlation between WMC and the ability to suppress neurological activity from a task-irrelevant stimulus. The research question tests the foundations of Lavie’s perceptual load theory; that early selection occurs, by testing if higher WMC enhances people’s ability to inhibit processing of task-irrelevant stimuli from low versus high load (i.e. the difference from low to high load should be smaller for high WMC than for low WMC). This was operationalised by measuring the correlation of WMC and auditory processing under low versus high visual load. Auditory processing was measured with auditory steady state responses (ASSR), and WMC was measured with an operation-letter span task. The results showed no significant correlation between WMC and ability to suppress task-irrelevant stimuli. Based on the data, it is not possible to conclude with certainty that effects of load on auditory processing are unaffected by WMC, because confidence intervals were large.

I denna studie har jämförelse gjorts mellan Interacoustics Eclipse och GSI Audera i samband med Auditory Steady-State Respons (ASSR) mätningar. Syftet med studien var att undersöka ASSR som metod, att utvärdera dess tillförlitlighet i jämfö­relse med tonaudiometri för personer med normal hörsel och personer med hörsel­nedsätt­ning. Avsikten var dessutom att undersöka om elektrod­placering­ på örsnibb eller på mastoid påverkade mät­resultatet, försökspersonens upplevelse av instrumen­­t­ens ljudstimuli, om de estimerade ASSR-värdena påverkades av att mättillfället påbörjades eller avslutades med Interacoustics Eclipse samt undersöka tiden för mätningarna. En experimentell studie genomfördes. Mätningarna som utfördes var tonaudiometri och ASSR, den senare uppmättes med Interacoustics Eclipse och GSI Audera på (n=20) vuxna med normal hörsel och (n=4) vuxna med hörselnedsättning. För personer med normal hörsel påvisades en god överensstämmelse mellan estimerade ASSR-värden och tonaudiometri för Interacoustics Eclipse, något sämre överensstämmelse för GSI Audera. Genomsnittlig mättid för båda instrumenten var ca 40 min. Resultaten visade att elektrodplaceringen inte har någon påverkan på ASSR-värden för Interacoustics Eclipse. Hälften av försökspersonerna upplevde att Interacoustics Eclipse hade ett behagligare ljudstimuli att slappna av till och den andra hälften upplevde GSI Audera som behagligast. De estimerade ASSR-värdena påverkades minimalt beroende på om mättillfället påbörjades eller avslutades med Interacoustics Eclipse.