Speech intelligibility of Parkinson’s disease patients evaluated by different groups of healthcare professionals and naïve listeners

Abstract

Introduction

Speech intelligibility, how well a listener comprehends the speaker’s message, is related to the listener’ expertise and type of the message conveyed. There is no evidence about speech intelligibility in different groups of healthcare professionals and naïve listeners.

Objectives

This study is the first to understand if there were differences in the speech intelligibility of Parkinson’s Disease (PD) patients by different experienced and naïve listeners, according to the speech stimuli and dysarthria severity.

Materials and methods

Randomly digitised audio-files (50 words and 50 sentences) of 10 PD patients, one without dysarthria and 9 with different dysarthria severities (3 each: mild, moderate and severe dysarthria), were collected from a database of 60 PD patients’ audio-files. A jury panel was formed by five different listeners groups including 10 speech and language therapists, 10 neurologists, 10 PD relatives, 12 PD patients, and 10 people from the general population. The jury panel transcribed single words and sentences from the audio recordings, the percentage correctly understood was calculated and the results were compared between the groups.

Results

Multiple comparisons showed significant speech intelligibility differences between healthcare professionals and naïve listerners in words (highest effect size, η² = 0.7) and sentences (the highest effect size: η² = 0.6). Pairwise comparisons revealed that those significant differences were specifically in words with moderate and severe dysarthria and sentences with all severity levels of dysarthria.

Conclusion

The groups of healthcare professionals who work with dysarthria are more likely to understand the PD patients’ speech than the groups of naïve listeners.

Keywords:

• Dysarthria
• intelligibility
• audio-perceptive analysis
• Parkinson’s disease

Acknowledgments

The authors gratefully acknowledge all participants for their voluntary collaboration in this study.

Disclosure statement

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. None of the authors have any conflicts of interest or financial disclosures to report.

Additional information

Notes on contributors

Joana Carvalho

Joana Carvalho Degree in Speech Therapy from the School of Health of the University of Aveiro. Master in neuroscience from the Faculty of Medicine of the University of Lisbon. Post-graduated in oropharyngeal dysphagia by the Epap Institute (I.EPAP). Working as a speech therapist at Campus Neurológico Senior since 2014. Researcher at the Instituto de Medicina Molecular, dedicated to the study of speech and swallowing disorders in movement disorders. Involvement in financed project in the field of the article: FraLusoPark-Dysarthria in Parkinson Disease project coordinated by Serge Pinto (Laboratoire Parole et Langage, Université Aix-Marselle/CNRS) and Joaquim Ferreira (Institute of Molecular Medicine, Faculty of Medicine of Lisbon) (http://dx.doi.org/10.1136/bmjopen-2016-012885).

Rita Cardoso

Rita Cardoso Degree in Speech Therapy from the School of Health of the University of Aveiro. Master in neuroscience from the Faculty of Medicine of the University of Lisbon. Post-graduated in oropharyngeal dysphagia by the Epap Institute (I.EPAP). Coordinator of the speech therapist therapy service at the Senior Neurological Campus in Torres Vedras, where she works exclusively with neurological pathology. Lecturer of Speech Therapy at the Alcoitão Health School of Sciences. Member of the Portuguese Society for Movement Diseases (SPDMOV) and the Portuguese Society for Speech Therapy (SPTF). Researcher at the Instituto de Medicina Molecular, dedicated to the study of speech and swallowing disorders in movement disorders. Involvement in financed project in the field of the article: FraLusoPark-Dysarthria in Parkinson Disease.

Isabel Guimarães

Isabel Guimarães Bachelor of Speech Therapy; Post-graduated in Lecturing and Administration from Alcoitão Health School of Sciences; PhD in Experimental Phonetics - University College London, currently Professor at the Alcoitão Health School of Sciences, Coordinator of the Master in Speech Therapy (specialization in Orofacial Motricity and Swallowing); Senior researcher at the Unit of Clinical Pharmacology and Therapeutics - Institute of Molecular Medicine - University of Lisbon; Founder and former editor-in-chief of the Portuguese Journal of Speech Therapy; Currently scientific Vice-President of the Portuguese Society of Speech Therapists; Involvement in financed project in the field of the article: FraLusoPark-Dysarthria in Parkinson Disease.

Joaquim J. Ferreira

Joaquim J. Ferreira Neurologist, having completed his medical training and subsequent PhD in Neurology at the Faculty of Medicine of the University of Lisbon, currently Professor of Neurology and Clinical Pharmacology and Director of the Laboratory of Clinical Pharmacology and Therapeutics at the Faculty of Medicine of the University of Lisbon, director of a Research Group at the Institute of Molecular Medicine and Clinical Director of the CNS-Campus Neurológico Senior, co-director of the Movement Diseases Panel of the European Academy of Neurology and former President of the European Section of the International Society for Parkinson's Disease and other Diseases of the Movement.