The Northwestern University Auditory Test Number 6 (NU-6) measure of speech discrimination was time compressed and presented to four age groups ranging from 54 to 84 years of age. Experimental stimuli were presented at sensation levels of 24, 32, and 40 dB to an equal number of right and left ears and male and female subjects. Results indicated that intelligibility decreased as a function of increasing time compression and age and decreasing sensation level. Changes in speech intelligibility associated with the aging process appear to be closely allied to changes in the temporal resolving power of the central auditory processing system.

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Time-compressed monosyllables have been studied relative to the assessment of central auditory disorders. In certain instances, sentential stimuli may be more useful than word lists in central auditory testing, particularly when results may be contaminated by concomitant peripheral hearing losses. Central Institute for the Deaf (CID) and Revised CID sentence lists and a contrived sentential approximation task were presented to 96 normal hearing young adults at time-compression ratios of 0%, 40%, 60%, and 70%, under sensation levels of 24 and 40 dB. The CID and RCID stimuli were more intelligible than the sentential approximations. The results are presented and discussed as they pertain to central auditory testing and are compared to earlier data using consonant-nucleus-consonant monosyllabic stimuli.

Time-compressed versions of the WIPI and PB-K 50 speech discrimination measures were presented at two sensation levels to 60 children divided into three age-groups of 20 each. Results showed that average intelligibility scores increased as a function of increasing age and sensation level and decreased with increasing amounts of time compression. The PB-K 50 measure was found to be more difficult than the WIPI for each age-group under each condition of time compression and sensation level. The several factors under study were found to interact. The results are discussed relative to open- versus closed-message set response tasks and the implications for audiological diagnoses of children with central auditory processing problems.

The effects of time-compressed monosyllabic CNCs on the auditory discrimination performance of 96 young adults with normal hearing were studied. Five conditions of time compression, 30% through 70% in 10% steps, plus a 0% control condition were presented at four sensation levels (8, 16, 24, and 32 dB). Ear presentation and list version were counterbalanced with these factors. Results indicated that intelligibility was inversely related to time-compression ratio and directly related to sensation level. Ear and list effects were minimal.