Clinical application of the Grason-Stadler otoadmittance meter.
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Biomedical subjects
Publications and source records attributed to S A Fausti.
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A practical monitoring procedure utilizing frequencies higher than those tested by conventional audiometry for the detection of ototoxicity has the potential for preventing or minimizing irreversible communication deficits in patients receiving aminoglycoside antibiotic therapy. If ototoxicity produced by these drugs could be detected before it progresses to involve the frequencies essential for communication, it might be possible to lower the dose or to change to another antibiotic to prevent a permanently handicapping hearing impairment. From a total of 77 patients monitored by serial audiograms, three case studies illustrate the various types of auditory sensitivity changes observed with high-frequency audiometry. Ototoxicity was generally detected by high-frequency auditory testing before it could be detected by conventional audiometric procedures. These cases demonstrate the utility of monitoring audition at frequencies higher than those tested conventionally in patients receiving aminoglycoside antibiotics.
An auditory brainstem response method is described for evoking responses to 4 high-frequency (8, 10, 12 and 14 kHz) tonebursts in the same amount of time normally required to obtain responses to single tonebursts. Reliability of responses to high-frequency toneburst stimuli presented in the conventional manner (one at a time) has been previously documented. In the present study, high-frequency tonebursts were presented to 20 normal-hearing subjects singly and in a 4-stimulus sequence. The reliability of resulting responses did not differ significantly between single- and multiple-stimulus test conditions. It is concluded that this sequenced-stimulus concept could be developed for use in serial monitoring of individuals receiving ototoxic agents as well as being broadly applicable to clinical situations in which patients cannot or will not respond voluntarily.
Clinical assessment of the perceptual characteristics of tinnitus usually includes an attempt to match the pitch of tinnitus to a pure tone. A standardized clinical protocol for tinnitus pitch matching does not yet exist, and there is a history of unsuccessful attempts to obtain such measures reliably. The present study was designed to evaluate new protocols for identifying the perceived pitch of tinnitus, with the objectives of reducing testing time and improving test-retest reliability. Two protocols ("Octave" and "Binary") were developed, each of which was patterned after the testing procedure previously developed at the Oregon Tinnitus Clinic and used to assess thousands of tinnitus patients. Both protocols use computer-automation to conduct testing; the protocols differ according to their specific testing algorithms. Twenty subjects with nonfluctuating tinnitus were each tested over two sessions. Results of testing revealed that both protocols could obtain pitch matches within 20 to 25 min. Reliability of responses was good for some subjects but not others, and the Binary protocol generally provided more reliable results.
This study was conducted to document test-retest reliability of hearing thresholds using our computer-automated tinnitus matching technique and Etymotic ER-4B Canal Phone insert earphones. The research design involved repeated threshold measurements both within and between sessions, and testing to evaluate the potential effect of eartip removal and reinsertion. Twenty normal-hearing subjects were evaluated over two testing sessions with the use of a fully automated protocol for determining thresholds with 1-dB precision. Thresholds were first obtained at 0.5-16.0 kHz, in one-third octave frequency steps (16 test frequencies). The octave frequencies were then retested, first without removing the eartips, then after eartip removal and replacement. Responses between sessions differed by an average of 2.5 dB across all 16 test frequencies, and 91.5 percent of the repeated thresholds varied within +/-5 dB (98.1 percent within +/-10 dB). Reliability of within-sessions thresholds was also good, and there was no effect of eartip removal and replacement.