Vowel production in children with myotonic dystrophy: A lip-tube perturbation study

Abstract

Myotonic dystrophy, a neurodegenerative disease that causes muscle weakness and difficulties in muscle relaxation after contraction, frequently affects orofacial articulatory dynamics leading to decreased speech intelligibility, particularly in children. We aimed to investigate the effects of myotonic dystrophy on sensorimotor relationships in children’s speech through a study of compensations for a lip-tube perturbation. We recruited fourteen 6- to 14-year-old French-speaking children diagnosed with myotonic dystrophy and 14 aged-matched typically developing children. They were asked to produce repetitions of the vowel /u/ with and without a 15-mm-diameter tube inserted between the lips. A synchronized ultrasound, Optotrak motion tracking system, and audio recording system was used to track lip and jaw displacement as well as tongue shape and position. Separate analyses were conducted on the first (F1), the second formant (F2), and the fundamental frequency (F0). Results revealed a significant main effect of group and an interaction between group and condition. Perceptual ratings of the produced vowels suggest that children with myotonic dystrophy rely more on auditory feedback than their typically developing peers. Together, results suggest that auditory feedback plays an important role in speech compensation, especially when the production system is impaired.Myotonic dystrophy, a neurodegenerative disease that causes muscle weakness and difficulties in muscle relaxation after contraction, frequently affects orofacial articulatory dynamics leading to decreased speech intelligibility, particularly in children. We aimed to investigate the effects of myotonic dystrophy on sensorimotor relationships in children’s speech through a study of compensations for a lip-tube perturbation. We recruited fourteen 6- to 14-year-old French-speaking children diagnosed with myotonic dystrophy and 14 aged-matched typically developing children. They were asked to produce repetitions of the vowel /u/ with and without a 15-mm-diameter tube inserted between the lips. A synchronized ultrasound, Optotrak motion tracking system, and audio recording system was used to track lip and jaw displacement as well as tongue shape and position. Separate analyses were conducted on the first (F1), the second formant (F2), and the fundamental frequency (F0). Results revealed a significant main effec...