PubMed · 7266964
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J C Morrill, M L Sterrett. 1981. Quality controls for audiometric testing.. https://pubmed.ncbi.nlm.nih.gov/7266964/
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OBJECTIVE: To determine if all children with enlarged vestibular aqueducts (EVAs) have development of uniform progressive sensorineural hearing loss (SNHL). To determine whether the size of the EVA correlates with severity, frequencies involved, and stability of SNHL. To determine if the audiologic pattern of SNHL correlates with likelihood of progression of SNHL. DESIGN: Retrospective study. SETTING: Children's National Medical Center, Washington, DC, a tertiary care center with a large otologic practice. PATIENTS: Fifteen children (26 ears) with EVA on computed tomographic scan. METHODS: History, physical examination, computed tomographic scans, and serial audiograms were reviewed. Factors analyzed included age at diagnosis, audiometric configuration (high tone, midtone, low tone, flat), degree of hearing loss at presentation, length of follow-up, and presence of associated inner ear anomalies. RESULTS: Nine ears had progressive SNHL, 16 ears had stable SNHL, and 1 ear had profound SNHL. The predominant audiologic configuration was flat. The audiogram configuration does not correlate with progression of SNHL. The size of the vestibular aqueduct does not correlate with the level, type, or progression of SNHL. CONCLUSION: Our study failed to uncover factors that might be predictive of progression of hearing loss. We conclude that until a better understanding of the natural history and pathophysiologic condition of EVAs is achieved, there is no surgical or other intervention that can be demonstrated as being efficacious.
Many methods of screening for hearing impairment are available. The aim of our study was to determine which ones were really used in 1992. At the request of the British Audiology Society, we conducted an inquiry into the organization of screening for deafness in neonates and infants in Europe. In practice all 6-9 month-old infants are tested with behavioural tests in every country. For the neonates, generally only those at risk for hearing-impairment (about 5%) were tested. The most widely used tests were behavioural ones. Only specialized centers used transient evoked otoacoustic emissions (TEOAEs). This last test assesses the active mechanical properties of the cochlea and allows detection of even mild or unilateral sensorineural deafness.
The ability to lateralize dichotic clicks with either interaural time delays (ITD) or interaural level differences (ILD) was tested in seven multiple sclerosis (MS) subjects who had normal audiograms. Along with the psychoacoustical tests, magnetic resonance images (MRI) of the subjects' brainstem were obtained. After matching each MRI section with the corresponding section of a computerized atlas of the brainstem, the parts of the auditory pathway affected by each MS lesion were determined. Of the seven subjects two performed normally with both types of interaural asymmetry and had no brainstem lesions involving the auditory pathway. Two subjects performed normally only with level differences, but perceived all the dichotic clicks with different ITDs in the center of the head; both had lesions involving the trapezoid body. Three subjects could not perform normally with either task, perceiving the clicks to the sides and never in the center for both ITDs and ILDs; all three had unilateral lesions of the lateral lemniscus. A multi-level decision making model is proposed to account for these results.