Practice Effects in Frequency Discrimination by Hearing Impaired Children

Abstract

The difference limens for frequency (DLF) at 250 and 500 Hz of 23 deaf and 21 hard-of-hearing children were measured in three practice sessions. Conditions included both fixed amplitude, where loudness could be confounded with pitch, and variable amplitude, where loudness and pitch varied independently. Results indicated: (1) The deaf group showed a significant decrease in size of DLF over the three test sessions. The hard-of-hearing group showed a significant decrease in size of DLF over the three test sessions for only one condition. A third group of children with normal sensitivity showed asymptotic performance on the first test session. (2) A moderate correlation between Hearing Level and size of DLF was found at 500 Hz but not at 250 Hz. (3) Significant differences in performance were found between the fixed- and variable-amplitude conditions. The reliability and the validity of the results are discussed and some implications for teachers of the deaf are mentioned.