Conceptualisation of deviations in intonation production in aphasia

Abstract

Background: Most studies of intonation disorder in brain‐damaged patients assume that normal intonation is made up of a single overall pitch contour that is holistically either “linguistic” or “affective”, and processed globally. However, data suggest that intonation may be processed in units smaller than the overall pitch contour, and that its disorder may be attributable to impaired ability to process aspects of those units. Aim: The present study was conducted to determine whether deviations in intonation production in aphasia are attributable to deficit in processing the global pitch (fundamental frequency) contour or components of it. Methods & Procedures: Two sentence types of two lengths produced by patients with fluent and nonfluent aphasia, as well as neurologically normal control participants, were evaluated acoustically and perceptually. The acoustic evaluation included measures of declination and identifiable components of the fundamental frequency (F0) contour. Outcomes & Results: For all groups, some measures differed according to sentence type whereas others differed according to sentence size. None of the size‐sensitive measures differed according to sentence type for any group. However, group differences were exhibited on other measures including declination. The fluent group performed closer to normal compared to the nonfluent group. All groups were perceptually indistinguishable. Conclusion: The acoustic deviations taken with the perceptual data point to a deficit that might be phonetic in nature. The abnormal production of some but not all F0 components by the patients lends support to the hypothesis that intonation is processed in units smaller than its overall F0 contour, and that its disorder in brain‐damaged patients may be attributable to deficit in processing aspect(s) of those units. Comments and suggestions of an anonymous reviewer on an earlier version of this paper are gratefully acknowledged. This research was supported by NIH (NIDCD) grant 5R03DC004955‐03.