Speech in Duchenne Muscular Dystrophy

Abstract

Introduction: The aim of this study was to assess the speech characteristics in Duchenne Muscular Dystrophy (DMD), by studying the speech acoustics and the relationship between speech, the extent to which tongue muscles are affected, and the vital lung capacity. Methods: 13 patients with DMD and 3 patients with Intermediate Muscular Dystrophy (age 19-32) participated in the study. Quantitative muscle ultrasounds of the tongue muscles were performed and the speech was both perceptually and acoustically assessed by the Radboud Dysarthria Assessment and the Dutch Sentence Intelligibility Assessment. The vital lung capacity was measured by spirometry. Results: There is a significant correlation between the dysarthria severity and the extent to which the tongue muscles are affected. There is also a significant relationship between the acoustic characteristics and the extent to which the tongue muscles are affected. The dysarthria severity had a significant correlation with the vital lung capacity. The speech in DMD turned out to be characterized by a reduced speech intelligibility, maximum phonation time and maximum phonation volume in comparison with normative data, but the maximum repetition rates and the fundamental frequency range appeared to be unaffected. Conclusion: The results suggest that both the reduced vital lung capacity and the extent to which the tongue muscles are affected influence the dysarthria severity in DMD. The reduced vital lung capacity seems to affect the speech acoustics more than articulatory deficits do.