Among complications associated with non-syndromic cleft lip and/or palate (NSCL/P) in school age children, conductive hearing loss has been thoroughly investigated because the symptoms are noticeable and the treatment is often easy to access. Research on central auditory processing disorder [(C)APD] has been rarely explored in this clinical population. However, children with NSCL/P have been reported to have delayed speech and language development, as well as poor academic performance in general compared to craniofacially normal peers, despite their peripheral hearing problems typically resolving with age. In order to investigate suspected (C)APD in children with NSCL/P, the present research program was initiated. The study aimed to utilize a comprehensive test battery to assess auditory status in children with NSCL/P, and to investigate whether they have a greater frequency of (C)APD compared to craniofacially normal children. 147 children with NSCL/P and 60 normal children were recruited. They were Mandarin speakers and attending regular schools. The children with NSCL/P did not have peripheral hearing problems at time of assessment. There were three types of assessment tools used in the present research program. Firstly, hearing health tests were conducted to evaluate peripheral hearing function. Case history and auditory questionnaire reports were completed by caregivers to obtain basic medical and developmental information (Chapter 3). Secondly, auditory behavioral tests of (C)APD functioning were administered, including a gap detection test and a speech in noise recognition test (Chapter 4). Thirdly, an auditory evoked potential (AEP) assessment was conducted as an objective evaluation of the central auditory nervous system (Chapter 5). Based on the results of this research program, it was concluded that, firstly, children with NSCL/P showed behaviors typically found in children with (C)APD when questionnaire results were considered. Children with cleft palate (CP) showed the most negative outcomes, and cleft lip (CL) group children showed results equivalent to craniofacially normal children. Secondly, behavioral assessment results showed that compared to control group children, maturation for temporal resolution abilities was delayed in children with NSCL/P. Also, the ability to use interaural timing and intensity cues for speech recognition in a noisy environment was poorer in children with CP and CLP. Finally, abnormal AEP findings in children with cleft suggested longer neural transmission times and delayed development of the auditory nervous system may occur in this population. In summary, the research program found that children with NSCL/P are at higher risk of auditory processing difficulties compared to craniofacially normal children. In addition, a comprehensive test battery is more appropriate for making an accurate diagnosis of (C)APD in this population than a single assessment protocol. The present research program has contributed to an enhanced awareness of potential (C)APD in children with NSCL/P, which had not been investigated using a comprehensive test battery for a large sample of children with cleft disorders in any previous studies. Since Chinese language specific assessment tools are limited, further studies to develop an appropriate, comprehensive test battery for the diagnosis of auditory processing disorder in Chinese children with oral cleft and to explore effective management of this disorder are required. / published_or_final_version / Speech and Hearing Sciences / Doctoral / Doctor of Philosophy

Please read the abstract in the section 00front of this document / Dissertation (MA (Communication Pathology))--University of Pretoria, 2006. / Speech-Language Pathology and Audiology / unrestricted

The ability to understand speech is, for all practical purposes, the most important aspect of hearing.¹ The most common method of assessing hearing is through pure tone audiometry. However, the great majority of pre- school children referred to an otologist or a hearing clinic for a suspected hearing difficulty, are unable to cooperate sufficiently to insure a reliable pure-tone audiometric test. Even after pure tone results have been established with children in this age group, the tester frequently may be in doubt as to the validity of the results. The reasons for failure to get reliable results with young children appear to be these:

This study concerns audiometric evaluation and prediction of hearing loss in the autistic child based on information derived from acoustic reflex thresholds. Two groups (autistic males and normal children) of five subjects each were utilized. Results indicated that the acoustic reflex method consistently predicted significantly higher hearing thresholds for autistic subjects than operant pure-tone audiometric procedures. Furthermore, the acoustic reflex thresholds were significantly less sensitive in the autistic group than in the normal group, suggesting that the acoustic reflex response is somehow altered in autistic individuals. These findings are consistent with earlier work which hypothesized that autistics, manifest an organic brain lesion which interferes with the propagation of auditory information.

published_or_final_version / Speech and Hearing Sciences / Master / Master of Science in Audiology