The training of rhythm for deaf children in a residential school using exaggerated stress patterns

Nineteen prelingual deaf children, 8 to 12 years of age, who were screened and found to have poor ability to imitate normal stress patterns, were selected from a residential school which used sign language as a means of communication. These children were evaluated with the Modified Children's Auditory Test (MCAT) for categorizing and imitating monosyllabic, trochaic, and spondaic stress patterns. There were five test items for each pattern. The test items were presented through headsets and a vibrator attached at the child's wrist. For the categorization task, the child put a block into a box that represented the envelope of the stress pattern. For the imitation task, the child imitated (spoke) the pattern twice. The tester judged the child's response as correct if the stress pattern was similar to the stimulus and incorrect if the stress pattern was different. The intelligibility of phonemes and the word was not used for the judgement. A test item was judged correct if at least one response was correct. There was no significant difference between the mean categorization score before and after training; however, the scores were high for both the pre- and post-tests. This suggests that the categorization task is easy for deaf children. There was a significant improvement in the imitation scores from 3.5, 1.7, 2.4 in the pre-test to 4.8, 3.6, and 3.9 in the post-test for monosyllabic, trochaic, and spondaic stress patterns, respectively. The acoustical analyses of the children's responses revealed: (1) the three acoustical parameters (i.e., amplitude, duration, and fundamental frequency) differed for correct and incorrect responses; (2) incorrect responses had some common characteristics (e.g., long duration of syllables, smaller contrast between the first and second syllables, additional syllables, and uncontrolled Fo contour); (3) the amount of change from incorrect to correct responses varied for some children.