Prosodic characteristics of prepausal words produced by patients with neurodegenerative disease.

Abstract

Prosody of patients with neurodegenerative disease is often impaired. We investigated changes to two prosodic cues in patients: the pitch contour and the duration of prepausal words. We analyzed recordings of picture descriptions produced by patients with neurodegenerative conditions that included either cognitive (n=223), motor (n=68), or mixed cognitive and motor impairments (n=109), and by healthy controls (n=28; HC). A speech activity detector identified pauses. Words were aligned to the acoustic signal; pitch values were normalized in scale and duration. Analyses of pitch showed that the ending (90th-100th percentile) of prepausal words had a lower pitch in the mixed and motor groups than the cognitive group and HC. The pitch contour from the midpoint of words to the end showed a steep rising slope for HC, but patients showed a gentle rising or flat slope. This suggests that HC signaled the continuation of their description after the pause with rising contour; patients either failed to keep describing the picture due to cognitive impairment or could not raise pitch due to motor impairments. Prepausal words showed longer duration relative to non-prepausal words with no significant differences between the groups. This suggests that prepausal lengthening is preserved in patients.