Imitative use of prosody following early right hemispherectomy : a case study

Imitation of loudness contour, intonation, and duration was examined pre- and post-surgically for a single subject undergoing right hemispherectomy. Twenty-six of the subject's attempted imitative utterances, collected and audio-recorded prior to and following right hemispherectomy, were assigned ratings based on their perceived similarity to the clinician's stimulus utterance. Comparisons of performance across the designated conditions were accomplished using a t-test for related samples revealing the following results: (1) The subject's imitation of Ioudness contour did not differ significantly in its similarity to the clinician's stimulus utterance between pre- and post-surgery conditions: (2) The subject's imitation of intonation tended to increase in similarity to the clinician's stimulus utterance following surgery; (3) The subject's imitation of duration increased in similarity to the clinician's stimulus utterance following surgery. These results contraindicated decreased performance in the imitative use of prosody by the subject following right hemisphere removal. Rather, her performance appeared unaltered for the parameter of Ioudness contour and noticably improved for the intonational and durational parameters. Additional analyses examining the relationship between the similarity rating and the complexity of each utterance failed to reveal significant correlations between these variables for any parameter. Thus, complexity did not apprearto confound the resultant data with regard to stimulus-response similarity, lending further support to the obtained results. It was concluded that in a very young individual, such as the investigated subject, functional lateralization may not be completed and that the capacity for some degree of cortical reorganization exists, at least with regard to the investigated parameters.