Cepstral Changes Following Intensive Voice-Focused Treatment in Parkinson's Disease.

Abstract

Objectives: The purpose of this study was to analyze cepstral changes following intensive voice-focused treatment in Spanish speakers with Parkinson's disease (PD). A secondary aim of the study was to explore the relationship between cepstral values across time and perceptual data across speech subsystems.

Study design/methods: This study followed a one-group pretest-post test design. The smoothed cepstral peak prominence (CPPS) of conversational sentences was analyzed pretreatment and post treatment and at a 1-month follow-up session in 15 Spanish-speaking individuals with PD. A secondary data analysis was then conducted to examine CPPS values relative to perceptual changes in voice quality (VQ), ease of understanding, articulatory precision, resonance (RES), and prosody across time points.

Results: A significant difference in CPPS was established between speakers with mild and moderate dysarthria at pre treatment only. No significant differences were observed between groups at post treatment or follow-up. Within groups, both sets of speakers evidenced significant increases in CPPS post treatment as well as from pre treatment to follow-up. A positive and statistically significant correlation was observed between CPPS scores and the perceptual values for VQ and RES, irrespective of the stage of treatment.

Conclusions: Intensive voice-focused treatment may lead to improved VQ, as measured by the CPPS, in ecologically valid contexts, such as those involving conversations, with gains maintained in the short-term. Additionally, this type of treatment may result in a positive distribution of effects involving not just perceived VQ but also improved perception of RES.