The Evaluation of Abnormal Voice Qualities in Patients with Amyotrophic Lateral Sclerosis

Objective: Voice abnormalities are among the symptoms occurring in patients with amyotrophic lateral sclerosis (ALS). They are divergent and range from hoarseness, through the excessive adduction of false folds, up to the weakness of the vocal folds. The aim of the study was to analyze the phonatory function of the larynx in ALS patients. Methods: Seventeen patients with ALS were evaluated with subjective perceptual voice assessment (including the GRBAS scale), videolaryngostroboscopy including voice range and maximum phonation time (MPT), and objective acoustic voice analysis with IRIS software (including evaluation of jitter, shimmer, mean fundamental frequency, and noise-to-harmonics ratio (NHR)). Examinations were performed three times at 6-month intervals. Results: Hoarseness, roughness, and breathiness of voice were all found more frequently in the majority of these patients. Voice range, amplitude of vibration, mucosal wave, and glottal closure showed significant abnormalities with repeated examinations. MPT was shortened especially among women with ALS. Acoustic analysis of voice among men showed increased jitter value in the first examination only, while jitter, shimmer, and NHR in women with ALS were increased in all examinations. Conclusions: Analysis of voice qualities among patients with ALS allows for the detection of various abnormalities associated with the natural progression of the disease.