A comparison of stutterers and nonstutterers on masking level differences and synthetic sentence identification tasks.

Ten stutterers and ten nonstutterers, matched for sex, were tested for Masking Level Differences (MLDs) at 500 Hz, and were evaluated on the Synthetic Sentence Identification test with Ipsilateral Competing Message (SSI-ICM) under message-to-competition ratios (MCRs) of 0, -10, and -20 dB. No significant differences on the SSI-ICM task were seen between groups, but the stutterers did produce significantly (p less than .01) poorer MLDs than the nonstutterers. This may be interpreted as support for Kent's (1983) hypothesis that stutterers may be poorer at temporal processing. In addition, the present results support the concept of a continuum of auditory processing ability, with normals and stutterers of different degrees of disfluency revealing decreasing performance measures.