Evaluation of the speech motor control system in amyotrophic lateral sclerosis

We examined 162 amyotrophic lateral sclerosis patients and a subsequent group of 81 patients, addressing clinical aspects of bulbar dysfunction. All patients with deglutition complaints also had speech symptoms. The jaw jerk reflex and gag reflex had no relation to speech symptoms. Fundamental frequency (F₀) range for /i/ failed to predict longevity. Patients without speech symptoms all spanned at least one octave in F₀ output. Tongue denervation on electromyography testing was not related to speech symptoms. Repetitive output of /pa/, /ta/, and /ka/, when performed at slow and fast rates, sometimes revealed substitution of voiced cognates as well as nasal consonants with the same place of articulation as for the voiceless stops, suggesting velopharyngeal dysfunction.