The hearing and understanding problems of the people with high frequency hearing loss are covered within the scope of this thesis. For overcoming these problems, two main studies, developing hearing loss simulation (HLS) and applying new frequency lowering methods (FLMs) were carried out. HLS was developed with the suprathreshold effects and new FLMs were applied with different combinations of the FLMs. For evaluating the studies, modified rhyme test (MRT) and speech intelligibility index (SII) were used as subjective and objective measures, respectively. Before both of the studies, offline studies were carried out for specifying the significant parameters and values for using in MRT. For the HLS study, twelve hearing impaired subjects listened to unprocessed sounds and thirty six normal hearing subjects listened to simulated sounds. In the evaluation of the HLS, both measures gave similar and consistent results for both unprocessed and simulated sounds. In FLMs study, hearing impaired subjects were simulated and normal hearing subjects listened to frequency lowered sounds with the specified methods, parameters and values. All FLMs were compared with the standard method of hearing aids (amplification) for five different noisy environments. FLMs satisfied 83% success of higher speech intelligibility improvement than amplification in all cases. As a conclusion, the necessity of using subject-specific FLMs was shown to achieve higher intelligibility than with amplification only. Accordingly, a methodology for selection of the values of parameters for different noisy environments and for different audiograms was developed.

Diss. (sammanfattning) Örebro : Örebro universitet, 2005. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

This research describes the development of communicative intention of young children with cochlear implants in order to study the relationship between the early communicative intention of these children and their later verbal communication. Five children under the age of three years with cochlear implants were selected from the records of the University of Stellenbosch, Tygerberg Academic Hospital’s Cochlear Implant Unit, Cape Town as subjects. Video recordings of each of the five subjects in unstructured free play interaction with their caregivers, before cochlear implantation and each six months after cochlear implantation over a period of two years were used to identify the development of their communicative intention. The Communicative Intention Inventory (Coggins&Carpenter, 1981) was used to classify the communicative behaviour of the subjects according to the types of communication functions that were used, as well as the way in which they expressed the functions of communication. Results of the study show that the development course of the functions of communication that the subjects used over a two-year period, were consistent with the development patterns found in younger children with normal hearing. There was however marked individual differences between the subjects during the transition from nonverbal to dominantly verbal ways of communication as far as the rate of development of verbal communication was concerned. A strong relationship was found among the five subjects regarding the use of the nonverbal communication functions, request for object or action and protest before cochlear implantation and their total verbal communication two years after cochlear implantation, which could account for these individual differences in the rate of verbal communication development after cochlear implantation. Indications for clinical application and future research were identified on the basis of these conclusions. The data collected during the research is seen as meaningful in clinical decision-making regarding the suitability of young children under the age of three years with a profound hearing loss for cochlear implantation and their therapeutic management. / Dissertation (M (Communication Pathology))--University of Pretoria, 2006. / Speech-Language Pathology and Audiology / Unrestricted

In South Africa, the current movement towards the inclusion of children with disabilities, including children with hearing loss, is likely to have far-reaching consequences for both teachers and learners. Undoubtedly, needs will arise from teachers during the transition, especially in the areas pertaining to the audiological and educational management of children with hearing loss. A hearing loss often negatively impacts on the development of the child’s auditory, language, speech, communication, literacy, academic, and psychosocial skills. The educational audiologist is uniquely skilled in managing the effects of hearing loss on the child’s educational development, and is a crucial member on the educational team. The educational audiologist as specialist in the management of children with hearing loss, is able to offer a wide range of support and assistance to teachers as well as children with hearing loss in the inclusive educational system. When teachers receive appropriate educational audiology services, they are enabled to provide quality education that strives to reach the full potential of every child with hearing loss. Therefore, an urgent need existed to determine the needs of teachers of children with hearing loss regarding an educational audiology service delivery model for use within the inclusive educational system. In order to comply with this need, a descriptive research design was developed comprising of a questionnaire survey followed by focus group interviews. The questionnaire survey explored the needs of 664 teachers of children with hearing loss. Focus group interviews were conducted with 19 teachers of children with hearing loss and these results were used to substantiate findings from the questionnaire survey. The results of the study indicated that the needs of teachers differ according to the sub-groups found among teachers, namely those teachers who mainly promote the use of spoken language and those who mainly promote Sign Language. Findings revealed that, although participants realised the importance of various aspects of development of the child with hearing loss, they generally did not realise the importance of receiving support from an educational audiologist. With respect to specifics in term of support, participants strongly recommended that teachers receive support in the acquisition of knowledge re the trouble-shooting of hearing aids, advocacy for the implementation of FM systems in inclusive classrooms and the development of speech production skills of the child with hearing loss in the inclusive environment. In addition, various suggestions were made regarding the structure of services rendered within the educational context. These findings were utilised in order to propose an educational audiology service delivery model for South Africa in the current timeframe. / Thesis (DPhil (Communication Pathology))--University of Pretoria, 2005. / Speech-Language Pathology and Audiology / unrestricted

Objective: To date, the main focus in frequency lowering hearing aid studies has been in relation to speech perception abilities. With improvements in hearing aid technology, there is a growing interest in musical perception as a dimension that could improve hearing aid users’ quality of life. The purpose of this study was two-fold: Firstly, to develop a test of music perception for adult hearing aid users and secondly, to evaluate the influence of non-linear frequency compression (NFC) on music perception with the use of the Music Perception Test (MPT) compiled by the researcher. Research design and research sample: Phase 1 entailed the compilation of the MPT and can be described as design-based. A quasi-experimental research design was selected to establish the structure of the method employed in Phase 2, which involved the fitting of participants (n=40) with NFC hearing aids. Objective data was obtained with the hearing aids with NFC active and inactive. Phase 3 was characterized by a survey design which elicited subjective impressions of the participants’ musical experiences with NFC active and inactive. Results: Results proved that normal hearing adults as well as adults using hearing aids were able to complete all the sub-tests of the MPT. Furthermore, the use of NFC resulted in a statistically significant improvement in hearing aid users’ perception of timbre and melody, but not of pitch. Overall, no statistically significant improvement in their perception of rhythm was observed, although their performance on some rhythm sub-tests improved significantly. The use of NFC also brought about a statistically significant improvement in hearing aid users’ perception of the music qualities of overall fidelity, tinniness and reverberance. Although participants experienced the loudness, fullness, crispness, naturalness and pleasantness of music more positively with NFC, these benefits were not statistically significant. Conclusion: The MPT can be used successfully for assessing music perception in hearing aid users within the South African context and may therefore result in more accountable hearing aid fittings. The use of NFC may increase hearing aid users’ appreciation of music whilst not influencing music perception negatively. Given that a large percentage of hearing aid users express a loss in enjoyment of music, audiologists should not ignore the possible benefits of NFC, especially if one takes into account that previous research indicated speech perception benefits with this technology. / Thesis (DPhil)--University of Pretoria, 2012. / Speech-Language Pathology and Audiology / Unrestricted

Objective: To evaluate the long-term safety and performance of four different vibroplasty couplers (round window, oval window, CliP and Bell coupler) in combination with an active middle ear implant. Methods: This was a multicentre, prospective, long-term study including 5 German hospitals. Thirty adult subjects suffering from conductive or mixed hearing loss were initially enrolled for the study, 24 of these were included in the final analysis with up to 36 months of postsurgical follow-up data. Bone conduction and air conduction were measured pre- and postoperatively to evaluate safety. Postoperative aided sound field thresholds and Freiburger monosyllable word recognition scores were compared to unaided pre-implantation results to confirm performance. Additional speech tests compared postoperative unaided with aided results. To determine patient satisfaction, an established quality-of-life questionnaire developed for conventional hearing aid usage was administered to all subjects. Results: Mean postoperative bone conduction thresholds remained stable throughout the whole study period. Mean functional gain for all couplers investigated was 38.5 ± 11.4 dB HL (12 months) and 38.8 ± 12.5 dB HL (36 months). Mean word recognition scores at 65 dB SPL increased from 2.9% in the unaided by 64.2% to 67.1% in the aided situation. The mean postoperative speech reception in quiet (or 50% understanding of words in sentences) shows a speech intelligibility improvement at 36 months of 17.8 ± 12.4 dB SPL over the unaided condition. The signal-to-noise ratio (SNR) improved by 5.9 ± 7.2 dB SNR over the unaided condition. High subjective device satisfaction was reflected by the International Inventory for Hearing Aids scored very positively. Conclusion: A significant improvement was seen with all couplers, and audiological performance did not significantly differ between 12 and 36 months after surgery.

Objective: To evaluate the safety and effectiveness of round window (RW), oval window (OW), CliP and Bell couplers for use with an active middle ear implant. Methods: This is a multicenter, long-term, prospective trial with consecutive enrollment, involving 6 university hospitals in Germany. Bone conduction, air conduction, implant-aided warbletone thresholds and Freiburger monosyllable word recognition scores were compared with unaided preimplantation results in 28 moderate-to-profound hearing-impaired patients after 12 months of follow-up. All patients had previously undergone failed reconstruction surgeries (up to 5 or more). In a subset of patients, additional speech tests at 12 months postoperatively were used to compare the aided with the unaided condition after implantation with the processor switched off. An established quality-of-life questionnaire for hearing aids was used to determine patient satisfaction. Results: Postoperative bone conduction remained stable. Mean functional gain for all couplers was 37 dB HL (RW = 42 dB, OW = 35 dB, Bell = 38 dB, CliP = 27 dB). The mean postoperative Freiburger monosyllable score was 71% at 65 dB SPL. The postimplantation mean SRT 50 (speech reception in quiet for 50% understanding of words in sentences) improved on average by 23 dB over unaided testing and signal-to-noise ratios also improved in all patients. The International Outcome Inventory for Hearing Aids (IOI-HA) quality-of-life questionnaire was scored very positively by all patients. Conclusion: A significant improvement was seen with all couplers, and patients were satisfied with the device at 12 months postoperatively. These results demonstrate that an active implant is an advantage in achieving good hearing benefit in patients with prior failed reconstruction surgery.

Objectives: The aim of the study was to describe the prevalence and nature of auditory and otological manifestations in adults with HIV/AIDS according to clinical examinations and self-reported symptoms. Auditory profiles of HIV individuals were compared to that of a matched control group. Study design: A descriptive, cross-sectional group design was utilized in the first section of the study while a comparative, control matched research design was used to compare the HIV group and matched control group. Methods: Two hundred HIV positive adult patients attending the Infectious Disease Clinic of the 1 Military Hospital were included through convenience sampling. Participants were interviewed, medical files were reviewed and clinical examinations, including otoscopy, tympanometry, pure tone audiometry and distortion product oto-acoustic emissions, were completed. A control group of 184 individuals were compiled, matched to 184 of the HIV infected participants according to age, gender, ethnicity as well as working environment. Audiological thresholds at 0.5kHz – 4kHz were compared among these groups. Results: A prevalence of self-reported tinnitus (26%), vertigo (25%) hearing loss (27.5%), otalgia (19%) and pruritis (38%) was recorded. The onset of hearing loss was reported to be mostly (82%) of a slow progressive nature. Abnormalities in tympanometry, otoscopy and oto acoustic emissions were found in respectively 41%, 55% and 44% of participants. Hearing loss greater than 25 dB (PTA) was recorded in 14% of participants compared to 39% for hearing loss greater than 15 dB (PTA). Although not statistically significant (p<.05), self reported vertigo, self reported hearing loss, OAE abnormalities, hearing loss (PTA>15dB and PTA>25dB) and occurrence of mild hearing loss occurred throughout the CDC categories which were used as a measure of disease progression. A statistically significant increase (p<.05) in sensorineural hearing loss was seen with disease progression. In the comparative section, statistically significant (p<.05) worse thresholds were found in the HIV group as opposed to the control group at all frequencies (0.5 kHz – 4 kHz). Conclusions: Auditory and otological symptoms occurred frequently in this sample, while an increase in some symptoms as well as hearing loss was seen throughout disease progression. Sensorineural hearing loss increased significantly through disease progression. Hearing loss occurred more frequently in HIV individuals as opposed to individuals in the control group, while hearing loss occur more frequently in the more advanced stages of HIV infection. / Dissertation (MCommunication Pathology)--University of Pretoria, 2011. / Speech-Language Pathology and Audiology / Unrestricted

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