Prosodic characteristics of English speakers with Alzheimer’s disease

Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder. A large amount of work has focused on the automatic detection of AD, but few have examined the underlying acoustic correlates. Through the analysis of 42 speakers (21 AD and 21 control), research by Martinez-Sanchez et al. have reported flattened pitch trajectories which distinguish Spanish-speaking AD patients from those of controls [Martinez-Sanchez et al., Psicothema 24(1), 16–21 (2012)]. The present study aims to determine whether a similar effect is found in a large-scale study of English speakers with AD. Prosogram [Mertens, in Proceedings of Speech Prosody (2004)] was used to assess pitch trajectories of 203 English-speaking participants (128 AD and 75 control) from Dementiabank’s Pitt Corpus [Becker et al., Arch. Neurol. 51(6), 585–594 (1994)]. AD patients exhibited greater pitch range and trajectories across phonation than controls, both within and across syllables. These preliminary findings conflict with previous observations of a flattened prosodic profile for AD patients. A possible reason for this discrepancy is a difference in speech elicitation tasks. Previous studies on Spanish-speakers used reading and delayed pronunciation tasks, whereas the present study utilizes a picture description task, a more natural elicitation method.