Discrimination of speech sounds based upon temporal envelope versus fine structure cues in 5- to 7-year-old children.

Purpose: To investigate the capacity of young children and adults with normal hearing to discriminate speech on the basis of either relatively slow (temporal envelope, E) or fast (temporal fine structure, TFS) auditory cues.

Method: Vowel-consonant-vowel nonsense disyllables were processed to preserve either the E or the TFS information in 16 adjacent frequency bands. The band signals were then recombined and resulting stimuli were presented for discrimination to adults or 5-, 6-, and 7-year-old children using an odd-ball paradigm. Discrimination scores (d') and response latencies were measured in each listener. No training was given to listeners.

Results: Overall, discrimination scores were high (d' >or=1) in all speech-processing conditions, and did not differ across age groups. Overall, and irrespective of age, greater discrimination scores and shorter response latencies were observed for E speech than for TFS speech.

Conclusions: These results suggest that normal-hearing children are able to encode and use E and TFS speech cues at adult levels by the age of 5 years. TFS- and E-coded speech stimuli might therefore prove to be a useful tool for the investigation of the developmental time course of speech perception, and for the early diagnosis of peripheral and central auditory processing disorders.