Acoustic characteristics of the Lombard effect from talkers with Parkinson’s disease

Abstract

Speech production in noise elicits the Lombard effect, characterized by an increase in vocal effort. In talkers with Parkinson’s disease (PD), noisy environments are a stressor to speech production. Recently, the intelligibility of speech from PD talkers speaking in noisy (additive multi-talker babble) and reverberant environments was shown to be more sensitive to both factors than speech from healthy talkers [Kopf et al., ASHA 7387 (2013)]. The current study investigated the acoustic properties of speech and how they change in noise and reverberation for PD talkers compared to healthy talkers. Healthy talkers increased their level and fundamental frequency in additive noisy environments and, to a lesser degree, in reverberant environments. PD talkers also changed their level and fundamental frequency but to a more limited extent compared to healthy talkers. Additional changes in speech production (speaking rate, articulation range, and voice quality) were observed in individual talkers from both groups.