Speech Movement Measures as Markers of Bulbar Disease in Amyotrophic Lateral Sclerosis

Abstract

Purpose The goal of this study was to identify the effects of amyotrophic lateral sclerosis (ALS) on tongue and jaw control, both cross-sectionally and longitudinally. The data were examined in the context of their utility as a diagnostic marker of bulbar disease. Method Tongue and jaw movements were recorded cross-sectionally ( n = 33 individuals with ALS, 13 controls) and longitudinally ( n = 10 individuals with ALS) using a three-dimensional electromagnetic articulography system during the production of the sentence Buy Bobby a puppy. The movements were examined for evidence of changes in size, speed, and duration and with respect to disease severity and time in the study. Results Maximum speed of tongue movements and movement durations were significantly different only at an advanced stage of bulbar ALS compared with the healthy control group. The longitudinal analysis revealed a reduction in tongue movement size and speed with time at early stages of disease, which was not seen cross-sectionally. As speaking rate declined, tongue movements decreased in maximum speed, whereas jaw movements increased in maximum speed. Conclusions Longitudinal analyses of sentence-level kinematic data show their sensitivity to early bulbar impairment. A change in articulatory kinematics can serve as a useful diagnostic marker for bulbar ALS and to track bulbar disease progression in a clinical setting.