It is estimated that approximately 360 Million people have a permanent disabling hearing loss (WHO, 2015). The majority of these people live in lower to middle income countries, where screening and follow-up treatment is not always accessible (WHO, 2015). School based hearing screening is one of the procedures that are not always available due to a number of challenges one of which include the high cost of audiometrical headphones. School based hearing screening is performed with an audiometrical headphones and audiometer, it usually can be used to test all school-aged children and adults. In an attempt to reduce the cost of school based hearing screening, this study evaluated the Sennheiser HD 202 II headphone to establish it as a widely available and cost-effective alternative for audiometrical headphones currently used. The headphones were compared to ISO standards (ISO 389-1, ISO 389-5 and ISO 389-9) and IEC standards (IEC 60318-1 and IEC 60645-1). The following characteristics of the headphone were compared: equivalent threshold sound pressure levels, attenuation, maximum permissible ambient noise levels, force of the headband, total harmonic distortion and frequency response. After evaluation the Sennheiser HD 202 II does not show the same standard as audiometrical headphones for diagnostic testing. The headphone can however be used for screening purposes if a few measures are taken into account. The correct ETSPL values should be used, disruptive background noise should be avoided and only the frequencies from the research (250- 1600 Hz) can be tested. once these measures are taken into account the Sennheiser HD 202 II proves to be a cost-effective alternative headphone for screening purposes. / Dissertation (M Communication Pathology)--University of Pretoria, 2017. / Speech-Language Pathology and Audiology / M Communication Pathology / Unrestricted

Approximately 80% of the adult and elderly population ≥65 years have not been assessed or treated for a hearing loss, despite the effect a hearing loss has on communication and quality of life (World Health Organization [WHO], 2013a). In South Africa, many challenges to the health care system exist of which access to ear and hearing health care is one of the major problems. This study aimed to develop and validate a smartphone-based digits-in-noise hearing test for South African English towards improved access to hearing screening. The study also considered the effect of hearing loss and English speaking competency on the South African English digits-in-noise hearing test to evaluate its suitability for use across native (N) and non-native (NN) speakers. Lastly, the study evaluated the digits-in-noise test’s applicability as part of the diagnostic audiometric test battery as a clinical test to measure speech recognition ability in noise. During the development and validation phase of this study the sample size consisted of 40 normal-hearing subjects with thresholds ≤15 dB across the frequency spectrum (250 – 8000 Hertz [Hz]) and 186 subjects with normal-hearing in both ears, or normal-hearing in the better ear. Single digits (0 – 9) were recorded and spoken by a N English female speaker. Level corrections were applied to create a set of homogeneous digits with steep speech recognition functions. A smartphone application (app) was created to utilize 120 digit-triplets in noise as test material. An adaptive test procedure determined the speech reception threshold (SRT). Experiments were performed to determine headphones effects on the SRT and to establish normative data. The results showed steep speech recognition functions with a slope of 20%/dB for digit-triplets presented in noise using the smartphone app. The results of five headphone types indicate that the smartphone-based hearing test is reliable and can be conducted using standard Android smartphone headphones or clinical headphones. A prospective cross-sectional cohort study of N and NN English adults with and without sensorineural hearing loss compared pure-tone air conduction thresholds to the SRT recorded with the smartphone digits-in-noise hearing test. A rating scale was used for NN English listeners’ self-reported competence in speaking English. This study consisted of 454 adult listeners (164 male, 290 female; range 16 – 90 years), of which 337 listeners had a best ear 4 frequency pure-tone average (4FPTA; 0.5, 1, 2 and 4 kHz) of ≤25 dB hearing level (HL). A linear regression model identified three predictors of the digits-in-noise SRT namely 4FPTA, age and self-reported English speaking competence. The NN group with poor self-reported English speaking competence (≤5/10) performed significantly (p<0.01) poorer than the N & NN (≥6/10) group on the digits-in-noise test. Screening characteristics of the test improved with separate cut-off values depending on self-reported English speaking competence for the N & NN (≥6/10) group and NN (≤5/10) group. Logistic regression models, that include age in the analysis, showed a further improvement in sensitivity and specificity for both groups (area under the receiver operator characteristic curve [AUROC] .962 and .903 respectively). A descriptive study evaluated 109 adult subjects (43 male, 66 female) with and without sensorineural hearing loss by comparing pure-tone air conduction thresholds, speech recognition monaural performance score intensity (SRS dB) and the digits-in-noise SRT. An additional nine adult hearing aid users (4 male, 5 female) was utilized in a subset to determine aided and unaided digits-in-noise SRTs. The digits-in-noise SRT was strongly associated with the best ear 4FPTA (r=0.81) and maximum SRS dB (r=0.72). The digits-in-noise test had high sensitivity and specificity to identify abnormal pure-tone (0.88 and 0.88 respectively) and SRS dB (0.76 and 0.88 respectively) results. There was a mean signal-to-noise ratio (SNR) improvement in the aided condition that demonstrated an overall benefit of 0.84 dB SNR. A significant individual variability between subjects in the aided condition (-3.2 to -9.4 dB SNR) and unaided condition (-2 to -9.4 dB SNR) was indicated. This study demonstrated that a smartphone app provides the opportunity to use the English digits-in-noise hearing test as a national test for South Africans. The smartphone app can accommodate NN listeners by adjusting reference scores based on a self-reported English speaking competence. The inclusion of age when determining the screening test result increases the accuracy of the screening test in normal-hearing listeners. Providing these adjustments can ensure adequate test performance across N English and NN English listeners. Furthermore, the digits-in-noise SRT is strongly associated with the best ear 4FPTA and maximum SRS dB and could therefore provide complementary information on speech recognition impairment in noise in a clinical audiometric setting. The digits-in-noise SRT can also demonstrate benefit for hearing aid fittings. The test is quick to administer and provides information on the SNR loss. The digits-in-noise SRT could therefore serve as a valuable tool in counselling and management of expectations for persons with hearing loss who receives amplification. / Thesis (PhD)--University of Pretoria, 2017. / National Research Foundation (NRF) / Speech-Language Pathology and Audiology / PhD / Unrestricted