Conventional hearing aid circuitry is often unable to provide children with hearing loss with sufficient high frequency information in order to develop adequate oral language skills due to the risk of acoustic feedback and the narrower frequency spectrum of conventional amplification. The purpose of this study was to investigate word recognition abilities of children with moderate-to-severe hearing loss using hearing aids with linear frequency transposition. Seven children with moderate-to-severe sensorineural hearing loss between the ages of 5 years 0 months and 7 years 11 months were selected for the participant group. Word recognition assessments were first performed with the participants using their own previous generation digital signal processing hearing aids. Twenty-five-word lists from the Word Intelligibility by Picture Identification (WIPI) test were presented to the participants in three test conditions, namely: at 55 dB HL in quiet, 55 dB HL with a +5 dB signal-to-noise ratio (SNR) and at 35 dB HL. The participants were then fitted with an ISP-based hearing aid without linear frequency transposition, and the word recognition assessments were repeated with different WIPI word lists under the same conditions as the first assessment. Linear frequency transposition was then activated in the ISP-based hearing aid and different WIPI word lists were presented once more under identical conditions as the previous assessments. A 12-day acclimatization period was allowed between assessments, and all fittings were verified according to the DSL v5 fitting algorithm. Results indicated a significant increase of more than 12% in word recognition score for some of the participants when they used the ISP-based hearing aid with linear frequency transposition. A significant decrease was also seen for some of the participants when they used the ISP-based hearing aid with linear frequency transposition, but all participants presented with better word recognition scores when they used the ISP-based hearing aids without linear frequency transposition compared to their previous generation digital signal processing hearing aids. This study has shown that linear frequency transposition may improve the word recognition skills of some children with moderate-to-severe sensorineural hearing loss, and more research is needed to explore the criteria that can be used to determine candidacy for linear frequency transposition. / Dissertation (MCommunication Pathology)--University of Pretoria, 2010. / Speech-Language Pathology and Audiology / Unrestricted

A substantial body of research points to the benefits of fitting hearing instruments that provides extended high frequency amplification. Most published research were done on adults or in controlled laboratory settings. It is therefore necessary for peadiatric audiologists to critically assess the effects that this extended high frequency amplification has on the individual child fitted with hearing instruments. A quantitative research method was selected to explore the possible correlations between extended high frequency amplification and the influence this extended high frequency amplification has on speech recognition and functional performance in children with mild to severe sensory neural hearing loss. A quasiexperimental design was selected. This design accommodated a one-group (single-system) pre-test versus post-test design. Baseline assessments were done and all participants were subjected to pre- and post-intervention assessments. Six participants were fitted with hearing instruments which provided extended high frequency amplification. A baseline assessment was done with current hearing instruments after which participants were assessed with the hearing instruments with extended high frequency amplification. Aided audiological assessments were done without the extended high frequencies after which participants were evaluated with the added high frequencies. Speech recognition testing and functional performance questionnaires were used to compare the outcomes obtained with and without the extended high frequency amplification. A t-test was used for hypothesis testing to determine if extended range amplification increased speech recognition abilities and functional performance, and if these increases were statistically significant. Results were varied where some participants performed better and some performed worse with the added extended range amplification during speech recognition testing and functional performances observed at home. These varied results were statistically insignificant. However, statistically significant evidence was obtained to indicate that extended high frequency amplification increased the functional performance observed at school. The study concluded that the paediatric audiologist should know the effect fitting hearing instruments capable of extended high frequency amplification have on speech recognition abilities and functional performances. Fitting hearing instruments with extended high frequency amplification should however be done with caution because not all children benefited from extended bandwidth amplification. This underlines the importance of following a strict evidence-based approach that incorporates objective and subjective assessment approaches. This will provide the paediatric audiologist with real world evidence of the success of the amplification strategy that is followed. / Dissertation (MCommunication Pathology)--University of Pretoria, 2012. / Speech-Language Pathology and Audiology / Unrestricted