Vocal Fold Diadochokinetic Function of Individuals With Amyotrophic Lateral Sclerosis

Abstract

This study relates over time the changes in voluntary opening and closing of the vocal folds (vocal fold diadochokinesis, or VFDDK) of patients with amyotrophic lateral sclerosis (ALS). The rate, pattern, and periodicity of VFDDK were examined for 12 ALS subjects with bulbar and 14 subjects with nonbulbar signs of the disease. The acoustical data were analyzed with a commercially available computer-based speech analysis system. ALS patients with bulbar and nonbulbar symptoms demonstrate reduced rate and aperiodic VFDDK as the symptomatology of the neuromotor system progresses. Individuals with bulbar signs show a greater change in vocal fold activity than do the nonbulbar group. Discussion of the clinical implications for initial diagnosis and monitoring of changes over time in motor control of laryngeal function is presented.