Effects of a prosody treatment program on the speech intelligibility of patients with Parkinson disease

Document Type : Original Articles


1 MS, Department of speech therapy, University of Social Welfare and Rehabilitation, Tehran, Iran

2 PhD, Associate professor, Department of Speech therapy ,University of Social Welfare And Rehabilitation, Tehran, Iran

3 Scientific staff, Department of Speech therapy, School of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran

4 Associate professor, Department of Psychology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran

5 MD, assistant professor of Neurologist, Department of Neurology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran



Introduction: Parkinson's disease (PD) is a progressive neurological disease that effects non-speech movements along with different aspects of speech production. Affecting respiratory, articulatory, phonatory mechanisms, the disease makes speech prosody deficient and decreases its intelligibility, therefore impairing communicative interactions. The main objective of this research was to evaluate the effects of a prosody treatment program on the speech intelligibility of 3 patients with PD. Material and Method: In this Quasi-experimental single-subject study,  an ABA stepwise multiple baseline design was adopted.  3 PD patients, who were selected through nonrandomized convenient sampling method, participated in a speech prosody treatment program for 12 sessions. Result: The newly designed treatment program was verified by speech-language pathologists ( CVR ≥0.62, CVI = 0.94). The effectiveness of the program was evaluated through the following methods: charting, visual analysis, Cohen’s effect size (d) and the percentage of clinical recovery. The Effect sizes of therapy in the three patients were greater than 0.8 and all patients showed an acceptable percentage of clinical recovery after the treatment. Conclusions: Based on the present results, the newly designed treatment program increased the speech intelligibility of the three patients participated in the study. Moreover, the follow-up assessment results showed that the beneficial gains of the treatment  were relatively stable for three to four weeks after the termination of the treatment. Key word: Parkinson, speech prosody, speech therapy, speech intelligibility

Volume 9, Issue 7 - Serial Number 7
March 2014
Pages 1281-90
  • Receive Date: 04 September 2013
  • Revise Date: 19 April 2024
  • Accept Date: 22 May 2022