Following vestibular schwannoma excision, a subset of cases has been reported in which hearing is present immediately after surgery, but is lost in the early postoperative period. Such cases have rarely been reported, and the postoperative audiological data collected from patients in these cases lacks the time resolution necessary to determine the pathophysiological mechanism responsible for the pattern of hearing loss. The present study aimed to more clearly define delayed hearing loss by collecting detailed data documenting changes in behavioural and electrophysiological auditory responses following vestibular schwannoma surgery. In particular, we aimed to use this data to determine the time course of changes in auditory function and to identify whether the site of impairment was cochlear or neural. Preoperative and daily postoperative monitoring of auditory function was performed in 19 patients undergoing vestibular schwannoma excision via the retrosigmoid approach at Christchurch Public Hospital. The pre- and postoperative assessment battery included pure-tone and speech audiometry, tympanometry, tone decay, distortion product otoacoustic emissions (DPOAEs), and auditory brainstem response (ABR) measurement. Intraoperative ABR was performed in four cases in which clear preoperative waveforms were present. Transtympanic electrocochleography (ECochG) was carried out if wave I was lost in the early postoperative period. Thirteen of the 19 patients suffered immediate anacusis following surgery and six had measurable hearing postoperatively. The behavioural and electrophysiological data collected in each case is discussed with regard to the likely pathophysiology of pre- and postoperative hearing loss. No patients demonstrated behavioural evidence of delayed hearing loss, however a gradual deterioration of ABR in the early postoperative period was observed in Case 16. ECochG and DPOAEs in this case indicated the presence of cochlear function although the patient presented with immediate postoperative anacusis in the ipsilateral ear. These results are consistent with postoperative retrograde degeneration of the cochlear nerve.

Sclerosteosis is a rare genetic bone dysplasia disorder characterised by generalised craniotubular bone modelling. Alongside many clinical appearances marked in sclerosteosis, the auditory system is considerably compromised on several levels during the disease progression. Extensive otolaryngological research on the history of sclerosteosis, the clinical presentation of sclerosteosis, radiographic studies and the gene causing the condition had been documented. No studies had been found describing the audiological profiles, auditory functioning and abnormalities for subjects with sclerosteosis. Thus the object of this study aimed to describe the auditory profile of subjects with sclerosteosis. A cross-sectional descriptive research design and quantitative research approach was followed to investigate the auditory characteristics of subjects with sclerosteosis. Subjects were selected from a database of patients with confirmed diagnoses of sclerosteosis. Ten subjects responded and provided written informed consent. Test procedures included otoscopy, tympanometry, acoustic reflexes, diagnostic pure-tone airand bone-conduction audiometry, speech audiometry, distortion product otoacoustic emissions (DPOAE), auditory brainstem responses (ABR) and computed tomographic (CT) scans. The subjects were assessed with a comprehensive audiological test-battery within a single test session lasting approximately two hours. A CT scan was conducted on a separate occasion shortly after the audiological data were obtained. Normal type A tympanograms were obtained in 50% (n=10/20) of ears. All subjects presented with mixed hearing losses varying from moderate (5%; n=1), severe (55%; n=11) and profound (40%; n=8) degrees across ears. Hearing loss configurations ranged from rising (15%), sloping (35%) and air-conduction thresholds peaking at 2000 Hz (50%). Air bone gaps (ABG) were larger in older subjects, although not statistically significant (p>.05). The CT scans indicated anatomical abnormalities of the external auditory canal, tympanic membrane, middle ear space, ossicles, oval window, round window and the internal auditory canal. The progressive abnormal bone formation in sclerosteosis involved the middle ear, the round and oval windows of the cochlea and internal auditory canal. The progressive abnormal bony overgrowth, which is the hallmark of sclerosteosis, led to functional impairment at various levels in the auditory system. The current findings provided a comprehensive auditory profile for sclerosteosis. Results might be utilised alongside future research findings to direct criteria and audiological indications for surgical and audiological intervention. / Dissertation (MCommunication Pathology)--University of Pretoria, 2013. / gm2014 / Speech-Language Pathology and Audiology / Unrestricted

Magister Artium (Social Work) - MA(SW) / Overwhelming evidence suggests that 90% of children with a hearing loss are born to hearing parents. Research indicates that often these hearing parents are ill-informed about the cause and type of hearing loss their child has, leading the hearing parents to feelings of grief and disempowerment. Many hearing parents at the time of the diagnosis experience emotional turmoil as the diagnosis is often unexpected, resulting in a plethora of questions asked. The research approach for the study was qualitative in nature as it set out to explore and describe the experiences of hearing parents of their child’s hearing loss. A phenomenological strategy of design was employed to capture the lived experience from the hearing parents. Data was collected by means of unstructured individual in-depth interviews with 11 hearing parents. Volunteer and snowball sampling were implemented so as to access hearing parents whose children had been diagnosed with hearing loss. Data was analysed according to Creswell (2007) and Klenke (2008) and the trustworthiness of the qualitative study was evaluated against the criteria that Guba described in Krefting (1991). Ethical considerations, such as voluntary participation, informed consent, confidentiality, anonymity, no harm done and debriefing, were adhered to. After the conclusion of the research analysis, the findings of the research were discussed and recommendations were made. The findings of the recommendations spoke to the better understanding of the emotions and challenges of hearing parents as well as putting forward suggestions for supportive coping mechanisms to be put in place to support hearing parents whose children have been diagnosed with a hearing loss.

This article summarizes the significant contributions of Fred H. Bess to the early detection of hearing loss in infants and children. Based on public health and educational policy, Bess challenged audiologists to view hearing screening as a responsibility that brought with it the need to develop screening tools that are effective in identifying hearing loss - whether for use with infants, preschoolers, or school-age children - and that adhere to important screening principles. A review of his influence on pertinent guidelines, position statements, and recommendations highlights his belief that early identification of hearing loss is critical if children are to overcome the significant obstacles presented by even mild and unilateral hearing losses. This section is followed by a review of seminal papers that stimulated research in universal newborn hearing screening programs and the detection of unilateral and minimal hearing loss. We conclude with a review of selected studies that build on Bess's earlier work and strive to drive our field forward to practices that are both evidence-based and effective in detecting hearing loss in children.

Research has shown that age-related hearing loss may have profound implications on all aspects of an individual's life, including cognitive abilities. The relationship between hearing loss and cognition has led to research which indicates an association between objective hearing loss and reduced driving performance in older adults. However, little research exists on the relationship between self-perceived hearing loss and driving confidence, particularly in the South African context. The current study aimed to identify possible associations between driving confidence and hearing loss, age, sex and driving safety among older adults. Data analysis indicated a significant increase in driving confidence after one month of first-time hearing aid use. An insignificant or weak relationship was found between self-perceived hearing loss and level of driving confidence. Age, sex and a combination of both were significantly associated with level of driving confidence. No association was found between pure-tone average and level of driving confidence or between pure-tone average and driving safety. Further research in this area could assist in advising legislation relating to licensing and road safety campaigns targeted at older adults, as well as expanding audiologists' duty of care to include counselling on the potential positive effects of hearing aid use on driving confidence.

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This study is designed to examine participants’ view of hearing loss as a critical health issue, the attitudes of people toward a person with a hearing impairment, the knowledge level of OSHA regulations pertaining to hearing loss, the general knowledge level of hearing loss and hearing impairment, and its causes, and participants attitudes towards wearing hearing protection. The study design is descriptive and correlational with data collected using a written questionnaire with a controlled population. Results were computed using the means and standard deviation for each factor. The findings indicate that additional education and awareness is essential if changes are to occur in the areas of general knowledge of hearing impairment, the acceptance of hearing protective devices in the work place or school, and better interaction and communication with those who exhibit a hearing impairment. One area of specific improvement must be in how agricultural instructors are trained in the field of safety so that students involved in agricultural sciences are better prepared to protect his/her hearing while performing activities found in the agricultural business.

Educational research on students with mild and moderate hearing loss (MMHL), who represent up to 15% of the student population in regular classrooms, provides neither consistent nor meaningful attention to their learning and social-emotional experiences in school contexts. The purpose of this research is to investigate the perspectives of students with MMHL to gain insight into how they, as learners, conceptualize and manage their hearing loss at school and to develop recommendations for researchers and educators. Reviewed literature includes both quantitative and qualitative research which relies heavily on teachers’ and parents’ perspectives and achievement scores over student perspectives. Literature also indicates that there are discrepancies in student reporting depending on methods of data collection. Three students with MMHL were asked directly during in-depth interviews to describe their experiences in educational contexts. Self Determination Theory (SDT) (Deci & Ryan, 1985) provides an analytical and organizing framework for social-emotional elements of these learners’ experiences based on three psychological needs: relatedness, competence, and autonomy. In addition to SDT, a discussion of disability identity development research (e.g., Gill, 1997) provides a supplementary conceptual tool to expand the latent meanings of these experiences and socially constructed elements that students with hearing loss negotiate. Findings provide descriptive accounts of participants’ lived experiences with MMHL in educational contexts. Emergent patterns and themes identify broadly defined yet coherent messages highlighting the importance that educators (a) understand the lived experience of students with MMHL, (b) recognize the inherent contradictions that can accompany this disability, and (c) attend to needs, to communication, learning, and social-emotional needs. Each case indicates that student needs are met inconsistently resulting in adverse consequences for self-determined learning and social-emotional well-being. It is recommended that classroom teachers proactively facilitate potential learning outcomes for students with MMHL by attending to not only academic and communication needs, but to social-emotional needs as well. Researchers in education must further investigate the population of students with MMHL to assess their strengths and to ascertain the type of supports and interventions from which they could benefit. / Thesis (Master, Education) -- Queen's University, 2010-09-19 17:27:44.048

Mitochondrial dysfunction causes moderate to profound hearing loss both in isolation and as a feature of multi-systemic mitochondrial disease. The m.1555A > G mitochondrial DNA (mtDNA) variant is associated with a predisposition to aminoglycoside ototoxicity and maternally inherited non-syndromic deafness. However, the reasons for the highly variable penetrance of the associated hearing loss have not yet been fully resolved. Aminoglycosides are a recognised modifier factor of the hearing loss, but cannot account for all hearing impaired carriers in multi-generational pedigrees, implicating additional co-segregating genetic factors. By identifying and characterising the c.3G > A SSBP1 variant as a nuclear modifier of m.1555A > G the work detailed in this thesis extends our understanding of mitochondrial-nuclear interactions in human disease. To ascertain the frequency of the m.1555A > G variant in patients with suspected mitochondrial hearing loss we surveyed the laboratories within the United Kingdom that undertake genetic testing for this variant. We determined that the variant was not found more frequently in patients with known hearing impairment providing further evidence that m.1555A > G does not cause hearing loss in isolation. These results strengthened the case for nuclear genetic modifiers as important contributors to m.1555A > G pathogenesis. We next identified a multi-generational family that transmitted the m.1555A > G variant with variable clinical penetrance of hearing loss. In addition, a cohort of sporadic individuals carrying m.1555A > G was used to test the hypothesis that a conserved genetic mechanism accounted for the phenotype in all carriers. To this effect, we undertook whole exome sequencing in selected familial and sporadic carriers of m.1555A > G, identifying a heterozygous start loss mutation in the core mtDNA replisome protein gene, SSBP1, that co-segregated with the m.1555A > G variant and the phenotype in the family. The SSBP1 variant lead to a perturbation of mtDNA metabolism, and was associated with multiple mtDNA deletions and mtDNA depletion in skeletal muscle. Fibroblasts from these patients also showed mitochondrial network fragmentation and reduced intra-mitochondrial protein synthesis in keeping with the co-existing m.1555A > G variant, leading to reduced proliferation rates under conditions of forced mitochondrial respiration. Our findings provide an explanation for the variable clinical penetrance of the disorder within these m.1555A > G carriers and highlight the importance of trans-acting modifiers in mitochondrial disease.