Date of Award

2018

Document Type

Open Access Thesis

Department

Communication Sciences and Disorders

Sub-Department

The Norman J. Arnold School of Public Health

First Advisor

Julius Fridriksson

Abstract

The ability to repeat speech is impaired in most individuals with aphasia. Recent evidence suggests damage to area Spt (boundary of the parietal and temporal lobes at the Sylvian fissure) may cause the repetition difficulties commonly seen in aphasia. This study examined if such repetition impairments are specific to speech or reflect a more general repetition deficit, and determined how regional and network brain damage predict repetition impairments. Participants in the chronic phase of stroke (N=47) listened to a series of ten five-second melodies that consisted of six tones and repeated the melody (by humming) following its presentation. The participants’ audio samples were rated based on their similarity to the target melody, using a sentiment scale. The sentiment scale included the following ratings: strongly negative, negative, neutral, positive, and strongly positive. The audio samples were given one of these ratings based on their accuracy compared to the target melody. These scores were compared with the Western Aphasia Battery (WAB) repetition subscores to relate real word repetition to melody repetition. Melody repetition scores were also compared to nonword repetition by using a nonword word repetition task. A moderate association between melodic repetition and speech (real word and nonword) repetition was observed. Several connections were implicated as predicting poorer performance on the three behavioral tasks. A common shared connection between melodic repetition and word repetition was between the left inferior frontal gyrus pars opercularis and the left precentral gyrus. Damage to the left supramarginal gyrus, an area commonly damaged in conduction aphasia, predicted poor performance on melodic, real word, and nonword repetition. Melodic repetition was also predicted by damage to the precentral gyrus. These results suggest that performance on melodic repetition and speech repetition are predicted by mostly distinct areas of damage with some overlap in dorsal stream areas.

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