Further characterization of the DFNA1 audiovestibular phenotype.

BACKGROUND: Autosomal dominant, nonsyndromic, hereditary hearing impairment in a large Costa Rican kindred is caused by a mutation in the human homolog of the Drosophila diaphanous gene. OBJECTIVE: To further characterize the phenotype of DFNA1 with comprehensive audiovestibular evaluation and computed tomography of the temporal bone. PATIENTS: One affected child and 2 affected adults of the Costa Rican kindred who harbor a mutation in the diaphanous gene. SETTING: Medical Center at the University of California, San Francisco. INTERVENTION: Otologic and neuro-otologic examination; pure tone audiometry, speech audiometry, and immitance testing; auditory evoked potentials, electrocochleography, and otoacoustic emissions; electronystagmography and vestibular autorotation tests; and computed tomography of the temporal bone. RESULTS: The youngest subject, an 8-year-old boy, had a mild hearing loss, intact stapedial reflexes, otoacoustic emissions at high frequencies, normal auditory evoked potentials, and electrocochleographic findings consistent with endolymphatic hydrops. The two adults had severe to profound bilateral sensorineural hearing impairment. Electronystagmography disclosed normal vestibular function. Computed tomography demonstrated normal external, middle, and inner ear structures. CONCLUSIONS: These results suggest that the early low-frequency hearing loss in this family is associated with endolymphatic hydrops. Elucidation of the role of the diaphanous gene in hearing will therefore lead to a better understanding of the mechanism of endolymphatic hydrops.

Transient evoked otoacoustic emissions: feasibility in the nursery.

OBJECTIVE: To assess the feasibility of obtaining transient-evoked otoacoustic emissions (TEOAEs) directly in the nursery, to examine the nature of failures in this population, and to determine the time requirements for this test relative to the auditory brain stem response (ABR). DESIGN: TEOAEs and ABRs were recorded from 149 ears, at bedside, in the recovery or intensive care nursery. Subjects were selected according to the risk criteria developed by the Joint Committee on Infant Hearing (1991). Parametric and nonparametric statistical procedures were conducted to describe demographics and test results, to evaluate TEOAE measures by subgroups, and to compare infants by pass/fail outcome. Multivariate techniques were applied to the data to test implicit hypotheses regarding the source of TEOAE failures. In addition, the time required to carry out each test was evaluated in an analysis of variance design. RESULTS: 63.5% of the ears studied passed both procedures, 5% failed both, and 31.5% passed the ABR but failed the TEOAE. Although infants who failed the TEOAE had lower birthweights, shorter gestational periods, and were younger at the time of testing, no statistical differences were found for nursery (intensive care nursery/recovery), bed type (isolette/open crib), ear (left/right), or gender. Infants < 38 wk postconceptional age had smaller TEOAE responses and lower noise levels than did those > 37 wk. There were no differences in environmental noise levels (at the microphone) for passed or failed ears or whether infants were in isolettes or open cribs. Statistically prolonged ABR wave I latencies (Z-scores) at 60 and 30 dB among infants who passed the ABR but failed the TEOAE indicated some obstruction to the acoustic stimulus, whereas TEOAE noise measures neither distinguished these groups nor identified this condition. Three summary times involved in the performance of these tests were obtained: (a) actual test time, measured from start to completion of data collection with a stopwatch; (b) total test time, defined by the actual test time plus the respective preparation, setup, and cleanup (ABR) time; and (c) time reported by the computer system during intrinsic sampling. There were no significant differences in actual or total test times, but these values were distinguished from the machine time, which represented an underestimate of the time required to effectively conduct each test. CONCLUSIONS: These findings show that TEOAEs can be acquired in the nursery, but the high false-positive rate suggests that alternative or additional screening methods, for example, the ABR, must also be available. It must be recognized that TEOAE failures increase test time, thereby negating any savings relative to ABR screening alone.

Progression of hearing loss following the completion of chemotherapy and radiation therapy: case report.

There have been scattered accounts reported in the oncology literature of progressive hearing loss following the conclusion of chemotherapy. In this case study, we report the audiologic findings of such a case. These data underscore the need for post-therapy monitoring in cases where threshold shifts are discovered during the course of drug administration.

Cognitive aspects of tinnitus patient management.

Despite the availability of several management procedures for tinnitus, many audiologists seem reluctant to engage in long-term rehabilitation of patients. Tinnitus patients are somewhat similar to chronic pain patients in that both groups suffer from intractable symptoms. A technique which has been effectively utilized in helping pain patients cope with their problems is cognitive-behavioral therapy. This approach can be applied with considerable success to tinnitus patients with the emphasis placed on treating the patient's reaction to tinnitus rather than the tinnitus itself. To accomplish this, maladaptive behaviors and thought patterns must be identified and then systematically altered via a program specifically designed for the individual. This procedure is analogous to many precepts governing aural rehabilitation.

The use of masking level differences in the identification of children with perceptual problems.

The purpose of this investigation was to determine whether masking level differences (MLD's) could differentiate between normal children and children with suspected auditory processing problems. MLD's for speech and 500-Hz tones were measured for an experimental group consisting of 24 normal-hearing children suspected of having auditory perceptual dysfunction. Fourteen children with normal auditory processing abilities and 11 normal-hearing adults comprised the control groups. Results indicated that (1) there was no difference between MLD's for "normal" children and normal adults; (2) there was no difference between speech MLD's for the two groups of children; however, (3) tonal MLD's for the children with suspected auditory perceptual problems were significantly lower than those for the normal groups. Using a cut-off tonal MLD of 7 dB, 79% of the experimental group were positively identified whereas only 12% of the normals were identified. The tonal MLD can be a strong addition to a central test battery, especially because it can be used with nonverbal children who cannot complete many tests because of limited linguistic skills.

Clinical rationale for using an overhead speaker in evaluation of hearing aids.

A variable that has received little attention in the psychoacoustic evaluation of the hearing aid is the position of loudspeakers with respect to the listener, particularly the azimuth of the loudspeaker, which is used for presenting the competing message. In the past, a variety of locations have been used, some of which can bias the outcome of the evaluation. For this reason, this article suggests the use of an overhead speaker to deliver the competing signal. The overhead placement provides a neutral location that is highly desirable for making reliable repeated speech performance comparisons. In addition, the overhead speaker can be easily adapted to the testing environment while it produces the effect of surrounding the listener with the competing signal.