The clinical value of oto-acoustic emissions (OAEs) for the identification of the integrity of outer hair cell function has been proven numerous times in research studies, and OAEs are commonly included in the audiological test battery used by audiologists. The technological advances in this field, however, require continuous research to determine the value of new equipment. The main objective of this study was to determine the test-retest reliability of distortion product oto-acoustic emissions (DPOAEs) and transient evoked oto-acoustic emissions (TEOAEs). The subjects were female adults between 18 and 25 years of age, and 30 ears were used for this study. All participants had normal middle-ear function, normal hearing sensitivity (pure tone thresholds) and present OAEs. DPOAEs and TEOAEs were performed at specific time intervals to determine the test-retest reliability, and an OAE-gram was generated by combining DPOAE and TEOAE test results. These measures were performed as an initial measure (M1), after five minutes (M2), after an hour (M3), after a week (M4) and after a month (M5). The test-retest reliability was calculated by analysing the statistics quantitatively. Results were analysed to determine the variance between each participant individually at different time intervals, and also to determine the variance of the group as a whole at different time intervals. Through this analysis high test-retest reliability between the different tests was proven. Inferential statistical Analysis of Variance (ANOVA) and Intraclass Correlation Coefficient (ICC) proved that the test-retest reliability of DPOAEs, TEOAEs and the OAE-gram (generated through a combination of the DPOAE and TEOAE results) was consistent throughout all periods of testing. The highest correlation existed between immediate re-measurements, while the largest difference was observed between M1 and M3. High test-retest reliability for all tests conducted at different time intervals from original measures were confirmed. Recommendations that arose from this study are further research in the normal hearing population for better generalization, research into specific variables between subjects, research with longer time between different tests, as well as the test-retest reliability in pathologic populations. / Dissertation (MCommunication Pathology)--University of Pretoria, 2017. / Speech-Language Pathology and Audiology / MCommunication Pathology / Unrestricted

KwaZulu-Natal has been ranked as having the fourth highest incidence of transmitted Multiple Drug Resistant-Tuberculosis (MDR-TB) in sub-Saharan Africa. Substantial literature exists indicating the permanent damage that MDR-TB medication has on hearing abilities. The purpose of this study was to describe the hearing function of adults on long term MDR-TB treatment from Murchison Hospital MDR-TB unit in the Ugu District in rural KwaZulu-Natal. The primary aim of the study was to review the possible changes in hearing function in a group of adults on long-term treatment for MDR-TB. Secondly, the study aimed to estimate the number of adults who may present with changes following MDR-TB treatment and establish if relationships exist between the audiological findings and factors such as age and gender. The design of the study was a retrospective comparative data review of 68 patient records, all of which underwent audiological investigations from the start of MDR-TB treatment over a five-month period. The study made use of descriptive and inferential statistics to analyse the data. Specific inferential statistical analysis included analysis of covariance as well as regression analysis. Results from the study showed changes in hearing function in Distortion Product Otoacoustic Emissions (DPOAEs) and Pure Tone Audiometry (PTA) results at all five audiological sessions and across a range of frequencies. 84% of the total sample presented with overall refer readings for DPOAEs and 98.53% of the group of adults presented with criteria indicative of ototoxic hearing loss, specifically a bilateral mild-profound sloping SNHL on clinical PTA results. In the total sample of patient records reviewed in this study, all 68 records showed a change in hearing function, be that changes in DPOAE function and/or changes in PTA thresholds, following long-term treatment for MDR-TB. Variations in the effects of gender and ear difference were minimal and non-significant in all results. Similar presentation, to ototoxic hearing loss, of other degenerative conditions exists; however these conditions were accounted for as exclusion criteria in this study. Therefore the only remaining cause of possible hearing deficit was that of ototoxicity. The study provided valuable data regarding hearing function in a population of adults on long-term MDR-TB treatment in South Africa. Furthermore, the study has highlighted the need for the establishment of standardised audiological monitoring programmes sensitive to ototoxic hearing loss, within the South African context where the incidence of Tuberculosis (TB) and MDR-TB is reportedly high.