الفهرس 
CENTRAL/TEMPORAL AUDITORY PROCESSINGOnly 14 pages are availabe for public view
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Abstract
Background: Auditory Temporal Processing (ATP) refers to the ability of the central auditory nervous system to encode and detect subtle changes in acoustic signals necessary for perception of speech and critical for normal auditory development. Though psycho-acoustic tests can efficiently measure this ability, electrophysiological tests are needed when behavioral assessment could not be done or fails to reveal clear pattern of deficits. Cortical auditory evoked potentials (CAEPs) are believed to reflect the neural detection and/or discrimination of sound underlying speech perception. When obtained in response to a stimulus that contains multiple time-varying acoustic changes such as speech, the resulting waveform is referred to as the acoustic change complex (ACC).
Objectives: To assess children with ATP disorders using ACC potential, and to correlate between electrophysiological and psychophysical ATP tests.
Methods: ACC potential was recorded in thirty children with ATP disorder ranging in age from 6 to 12 years. Stimuli used were 500 msec. with spectral change (/i/ to /u/ and /u/ to /i/ vowels), temporal change (50 msec. to 150 msec. gaps-in-1000 Hz tones) and frequency change (0%, 10%, 25%, 50% using 1000 Hz tone). ACC response parameters were studied and compared to GIN, AFT, PPD and PPS test results.
Results: ACC percent identification ranged from 40% to 100% using the fore-mentioned stimulus parameters. Tonal stimuli were more efficient than speech stimuli in eliciting ACC. Compared to normal children; there was a significant decrease in ACC percent identification, prolonged latency and decreased amplitude. Results of correlation studies between electrophysiological and psychophysical tests will be presented.
Conclusions: ACC potential using short duration stimuli could be of help in the diagnosis of ATP disorder once suspected in children who cannot be evaluated behaviorally. However, more research is needed to document the complex relationship between ACC responses and psychoacoustic test results in this population.