Effect of clear speech intervention program on speech intelligibility in persons with idiopathic Parkinson’s disease: A pilot study

Abstract

Purpose: This preliminary study was designed to assess the feasibility of Clear Speech Intervention Program (CSIP) on improving speech intelligibility of persons with idiopathic Parkinson’s disease (PD). Clear Speech is a behavioural approach which focuses on improving speech intelligibility of persons with PD within a relatively short frame of time.

Method: A single group pretest-posttest design was used to assess the effectiveness of CSIP. Fifteen adults diagnosed with PD participated in 8 sessions of CSIP with each session lasting 45–50 minutes over a period of 4 weeks in South Korea. All the data were collected in a quiet room with an ambient noise level of equal to or less than 40 dB SPL. Data on acoustical/aerodynamic, auditory-perceptual, and self-perceptual measures were obtained pre- and post-intervention. The Phonatory Aerodynamic System (PAS) was used to analyse acoustical/aerodynamic data.

Result: The acoustical/aerodynamic assessment revealed statistically significant (p < 0.01) improvements in habitual pitch, pitch range, speaking rate, and number of respirations. In the auditory-perceptual assessment, statistically significant (p < 0.01) improvements were observed in overall speech intelligibility, tone, intonation, intensity, and articulation. Medium to large effect sizes were observed for significant results. The Pearson correlation analysis showed significant (p < 0.01) and strong correlation between articulation and speech intelligibility.

Conclusion: The preliminary data has provided promising results and warrants future large-scale studies with suitable controls. Additionally, future research must focus on investigating long term effects of the intervention.

Keywords:

• Hypokinetic dysarthria
• Parkinson’s disease
• Clear Speech
• speech intelligibility
• hyperarticulation

Acknowledgement

I would like to thank my advisor Dr. Ko. This work would not have been possible without his guidance.

Declaration of interest

The authors have no conflicts of interest relevant to this article to declare.