Recently, researchers have attempted to increase the time efficiency of the smartphone DIN test by decreasing the number of presentations of the DIN. One suggestion was to use a variable step size based on the correctness of digits identified within the triplet. In contrast, another suggested using a fixed signal-to-noise ratio (SNR) presentation level for all presentations of the DIN test and producing a pass/fail result based on whether a 95% recognition level was reached. This study aimed to compare three novel DIN test procedures as a potential way to improve efficiency with acceptable reliability using smartphone technology. / Dissertation (MA (Audiology) )--University of Pretoria, 2021. / Speech-Language Pathology and Audiology / MA (Audiology) / Unrestricted

Objective: This study evaluated the reliability of the digits-in-noise (DIN) test application across various low and high-end digital devices utilizing different transducers and sound file types. Design: The study utilized a cross-sectional within-subject design. Methods: The study consisted of two objectives. In the first objective, 40 normal hearing participants aged between 18 to 24 years (mean: 20; SD= 1.9) were recruited. Speech Reception Thresholds (SRTs) across Android smartphones (one low-end and one high-end smartphone), as well as an Android tablet coupled with different transducers (headphones and earphones) were compared. For the second objective, participants comprised of 12 normal-hearing females aged between 23 to 24 years (mean: 23, SD= 0.5). SRTs were compared across three different sound file types (OGG file, AAC file and MP3 file). Results: There was no significant difference in the SRTs between electronic devices or transducers used (p< 0.05). Furthermore, between the different sound files used, the difference was also not significant (p< 0.05). Conclusions: The DIN test is reliable when conducted across different electronic devices, regardless of the transducer or sound file type used. Therefore, the DIN test is clinically valid when downloaded and performed on Android devices despite the cost of the device thus offering greater usability in a variety of audiological contexts. / Dissertation (MA)--University of Pretoria, 2019. / Speech-Language Pathology and Audiology / MA / 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

Decentralised detection and monitoring of hearing loss can be supported by new mHealth technologies using automated testing, which can be facilitated by minimally trained persons. These technologies may prove particularly useful in an infectious disease (ID) clinic setting where patients are at high risk for hearing loss. The current study aimed to evaluate the clinical utility of mobile and automated audiometry hearing health technology in an ID clinic setting. The current study was exploratory as it aimed to determine whether smartphone automated audiometry and South African English Digits-In-Noise (SA Eng DIN) smartphone applications could be utilised in an infectious disease clinic setting to monitor an HIV-related hearing loss in a feasible and time efficient way. Smartphone automated audiometry (hearTest™) and speech-in-noise testing (SA English Digits-In-Noise (DIN) test) were compared with manual audiometry at 2, 4, and 8 kHz. Smartphone automated audiometry and the DIN test were repeated to determine the test re-test reliability. Two hundred subjects (73% female and 27% male) were enrolled. Fifty participants were re-tested with the smartphone applications. Participants’ ages ranged from 18 to 55 years with a mean age of 44.4 (8.7 SD). Threshold comparisons were made between smartphone audiometry testing and manual audiometry. Smartphone automated audiometry, manual audiometry, and test re-test measures were compared to determine the statistical significance of any differences observed using the Wilcoxon signed-ranked test. Spearman rank correlation test was used to determine the relationship between the smartphone applications and manual audiometry, as well as for test re-test measurements. For all participants, 88.2% of thresholds corresponded within 10 dB or less between smartphone audiometry and manual audiometry. There was a significant difference (p>0.05) between smartphone and manual audiometry for the right ear at 4 and 8 kHz and the left ear at 2 and 4 kHz respectively. No significant difference was noted (p>0.05) between test and re-test measures of smartphone technology except at 4kHz in the right ear in smartphone automated audiometry. The absolute average difference between the initial and re-test of DIN testing was 1.2 dB (1.5 SD). No significant difference was noted in the test re-test measures of the DIN test (p < vii 0.05). A correlation coefficient of 0.56 was present in the DIN test re-test measures when the Spearman rank correlation test was administered. Smartphone audiometry with calibrated headphones provides reliable results and can be used as a baseline and monitoring tool at ID clinics. / Dissertation (MA)--University of Pretoria, 2017. / Speech-Language Pathology and Audiology / MA / Unrestricted

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