Research was conducted on twenty-seven preoperative myringotomy patients to clarify the correlation between tympanometry type and the presence of middle ear effusion. Test results indicate that the relationship between tympanometry and middle ear effusion is dependent on the amount of fluid present. In impacted ears primarily Type B tympanograms were obtained whereas for less than impacted ears all tympanogram types were seen. Also suggested was that a combination of height of the tympanogram and the amount of negative pressure may be diagnostically more important than negative pressure alone as an indicator of effusion. It was recommended that other measures in addition to tympanometry be employed in the diagnosis of middle ear effusion and that further research is needed to achieve optimal use of impedance audiometry.

Effectiveness of impedance audiometry in diagnosing serous otitis media in children was examined in this study. The impedance test battery was performed on seventy-six ears of pre-myringotomy children (Mean age: 4.6 years). The status of the middle ear was assessed by the operating physician during surgery, and impedance results were correlated with the operative findings. Middle ear effusion was the variable that most influenced impedance results. Acoustic reflex threshold and tympanometry were the most sensitive tests in predicting effusion. Multiple correlations between these tests and the presence of significant effusion indicated that both measures together are diagnostically more sensitive than either test alone. Also, reflex measurement at one test frequency is as accurate a predictor of effusion as reflex measurement at all frequencies.

Rapid implementation of universal newborn hearing screening programs has exposed a need for a reliable test of middle ear function for timely identification of middle ear pathology and for differentiation between true sensorineural and conductive hearing losses. Use of higher probe tone frequencies for the assessment of immitance measures have proven to be more reliable and accurate in identifying MEE in infants. However a lack of classification-guidelines and age specific normative data exists. This study investigated the characteristics and normative values of high frequency tympanometric and acoustic reflex results for infants (n = 936 ears). Participants were 510 infants (262 male, 248 female) aged 0 – 12 months (mean age = 12.8 weeks) recruited from primary health care and immunization clinics in a South African community. A three-part procedure was performed on each test ear: 1) OAEs were recorded and pass results served as control variable for normal middle ear functioning; 2) 1000 Hz probe tone admittance, susceptance and conductance tympanograms were recorded and analysed in terms of shape, tympanometric peak pressure and maximum (peak) admittance; 3) 1000 Hz probe tone acoustic reflexes, measured with a 1000 Hz ipsilateral stimulus, were recorded and thresholds determined. Significant associations were observed between tympanogram shape, and OAE pass or fail results. 93% of ears with an OAE pass result displayed peaked tympanograms, while 79% of ears with absent OAE’s displayed flat tympanograms. Single peaked tympanograms were recorded in 782 ears (84%), double peaked tympanograms in 41 (4%) ears and flat sloping tympanograms in 112 (12%) ears. Admittance (Ya) tympanograms for the total sample displayed a mean admittance value of 2.9 mmho, with a standard deviation of 1.1 mmho. The 90th percent range was determined at 1.5 mmho (5th percentile) to 4.9 mmho (95th percentile). Mean tympanometric peak pressure in Ya tympanograms was 0.1 daPa, with a standard deviation of 61 daPa. The 90th percent range was -110 daPa to 90 daPa for the 5th and 95th percentiles respectively. Gender specific norms indicated a higher admittance for male ears. Age specific norms indicate a gradual increase in admittance indicating the need for age specific normative classification systems. Ipsilateral 1000 Hz stimuli acoustic reflex measurement proved successful with a 1000 Hz probe tone and present reflexes were recorded in 84% of ears tested. Significant association between acoustic reflex presence, OAE pass and peaked tympanogram results were observed. The normative tympanometric values derived from the cohort may serve as a guide for identification of middle ear effusion in neonates. High frequency tympanometry in combination with acoustic reflexes proves a useful measure for verifying middle ear functioning in young infants. / Dissertation (M (Communication Pathology))--University of Pretoria, 2006. / Speech-Language Pathology and Audiology / M (Communication Pathology) / unrestricted

Apart from isolated programs in private and public health care sectors, South Africa has no existing systematic public infant hearing screening program at community level. As a result, early identification of hearing loss is certainly not being attained for the majority of infants in South Africa with far-reaching effects for individuals, families and society at large. Screening programs at primary health care immunization clinics have been proposed as an alternative to hospital-based programs in South Africa. The objective of this study was to evaluate the first systematic community-based infant hearing screening program in a developing South African community in the Western Cape. A combined descriptive and exploratory research methodology was followed incorporating aspects of a program evaluation design. The study was of a quantitative nature and the required data were collected by means of a questionnaire and OAE testing conducted by clinic nurses on subjects. A community-based universal infant hearing screening program initiated at eight primary health care clinics in the Cape Metropolitan area was evaluated over a 19-month research period. During this time 6227 infants who were candidates for screening attended their 6, 10 or 14-week immunization visit at the relevant clinic. Clinic nurses were trained as screening personnel. A two-stage distortion product otoacoustic emissions screening protocol was utilized. The target disorder for this study was bilateral permanent congenital and early onset hearing loss and infants referring the first screen were scheduled for a 4-week follow-up visit at the clinic. Diagnostic audiological and medical evaluations were scheduled at referral hospitals when indicated. The study evaluated the efficacy of the program based on coverage, referral and follow-up rates and diagnostic outcomes according to guidelines specified by the Health Professions Council of South Africa 2007 Position Statement. Overall coverage rate across the eight clinics was 32.4% with 2018 infants (aged 0- 14 weeks) screened. The mean age of the sample at first stage screen was 3.9 weeks of age and 13.5 weeks of age for first hospital visit. Overall first stage screen referral rate was 9.5% with 62 subjects (3%) referred for diagnostic services at hospital level after a follow-up screen. The average follow-up rate for rescreens at clinic level was 85.1% and for initial diagnostic assessments at hospital level it was 91.8%. Although minimal hearing loss was not the primary focus of the screening program the outcomes did include those subjects with fluctuating conductive hearing loss and permanent unilateral hearing loss. Prevalence rates were 4.5/1000 with significant hearing loss, including sensorineural (1.5/1000) and conductive (3/1000) losses, and 12.9/1000 for subjects with middle ear effusion.<p-> The community-based infant hearing screening program was valuable in attaining high follow-up return rates but reaching sufficient coverage may require dedicated screening personnel as opposed to existing nursing personnel. Furthermore, consideration of an alternative community-based platform such as midwife obstetric units may improve coverage and referral rates and prevalence of permanent congenital and early onset hearing loss. / Dissertation (MCommunication Pathology)--University of Pretoria, 2013. / Speech-Language Pathology and Audiology / Unrestricted