Loudness and rate perception in Parkinson's disease

Abstract

In speech communication, Parkinson’s disease (PD) is typically discussed in terms of its production consequences. However, a small but growing literature indicates that PD may also result in deficits in the perception of loudness and rate information in speech. In the present study, we focus on the extent to which the perceptual deficits in PD are limited to speech or shared with other modalities, and the degree to which these deficits are dependent solely on perception or are also found in tasks of learning. To assess these questions, people with PD and age-matched controls perform two tasks: an AXB task of speech rate or intensity discrimination, and a simple learning task testing participants’ ability to group versions of a sentence based on their rate or intensity properties. For the AXB task, participants perform three additional versions of the task with stimuli that vary in their speech-like properties: time-reversed speech, pure tones, or visualizations. Preliminary data indicates that for control participants, all the continua are discriminated at above-chance performance and that participants can learn to group sentences based on both rate and intensity. Performance for the people with Parkinson’s Disease displays a great deal of variability.