Brief-Tone Audiometry

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Brief-tone audiometry involves measuring the thresholds of tones having very short durations. It
is the clinical application of temporal summation (integration), which occurs when sounds are shorter
than about one third of a second. Three normal-hearing people need a 10 dB level change to compensate for a 10-times change in duration; however, a smaller level change is needed for patients with cochlear impairments to offset a 10-times change in duration (Sanders & Honig 1967; Wright 1968, 1978; Hattler & Northern 1970; Barry & Larson 1974; Pedersen 1976; Olsen, Rose, & Noffsinger 1974; Chung & Smith 1980). In other words, the intensity-duration relationship (the temporal integration function) is typically shallower than normal when there is a cochlear impairment. This can be seen by comparing frames a and b in Fig.

Brief-tone audiometry usually involves Bekesy audiometry, which is why it is discussed at this point. However, other approaches have also been used. The basic testing method is quite simple. Bekesy audiograms are obtained using pulsing tones with various durations, and the resulting thresholds are assessed to determine how much of a threshold change is needed to offset a duration difference. The clinician might test enough durations to plot a diagram such as those in the figure, or test at just two represent listentative durations. Wright (1978) suggested that comparing the thresholds for tones having 20 and 500 ms durations is an efficient clinical approach. Normal and cochlear-impaired ears are typically distinguished with brief-tone audiometry, but the principal clinical question deals with distinguishing between cochlear and retrocochlear disorders. Early findings were optimistic (Sanders, Josey, & Kemker 1971), but subsequent work found too much overlap between the results for cochlear and retrocochlear disorders for brief-tone audiometry to be a viable diagnostic test in this regard (Pedersen 1976; Stephens 1976; Olsen et al 1974; Olsen 1987).



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