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Objective: To study objectively auditory temporal processing in a group of nor mal hearing subjects and in a group of hearing-impaired individuals with audito ry neuropathy (AN) using electrophysiological and psychoacoustic methods. Method s:Scalp recorded evoked potentials were measured to brief silent intervals (gaps ) varying between 2 and 50 ms embedded in continuous noise. Latencies and amplit udes of N100 and P200 were measured and analyzed in two conditions:(1) active, w hen using a button in response to gaps;(2) passive, listening, but not respondin g. Results: In normal subjects evoked potentials(N100/P200 components) were reco rded in response to gaps as short as 5 ms in both active and passive conditions. Gap evoked potentials in AN subjects appeared only with prolonged gap durations (10-50 ms). There was a close association between gap detection thresholds mea sured psychoacoustically and electrophysiologically in both normals and in AN su bjects.Conclusions: Auditory cortical potentials can provide objective measures of auditory temporal processes. Significance:The combination of electrophysiolog ical and psychoacoustic methods converged to provide useful objective measures f or studying auditory cortical temporal processing in normals and hearing-impair ed individuals. The procedure used may also provide objective measures of tempor al processing for evaluating special populations such as children who may not be able to provide subjective responses.
Objective: To study objectively auditory temporal processing in a group of nor mal hearing subjects and in a group of hearing-impaired individuals with auditory neuropathies (AN) using electrophysiological and psychoacoustic methods. Method s: Scalp recorded evoked potentials were measured to brief silent Latencies and amplitudes udes of N100 and P200 were measured and analyzed in two conditions: (1) active, w hen using a button in response to gaps; (2) passive , listening, but not respondin g. Results: In normal subjects evoked potentials (N100 / P200 components) were reco rded in response to gaps as short as 5 ms in both active and passive conditions. Gap evoked potentials in AN subjects gap durations (10-50 ms). There was a close association between gap detection thresholds mea sured psychoacoustically and electrophysiologically in both normals and in AN su bjects. Conclusions: Auditory corti Significance: The combination of electrophysiological and psychoacoustic methods converged to provide useful objective measures f or studying auditory cortical temporal processing in normals and hearing-impair ed individuals. The procedure used may also provide objective measures of tempor al processing for evaluating special populations such as children who may not be able to provide subjective responses.