Tongue force in normals and in dysarthric patients with amyotrophic lateral sclerosis.

Tongue force, rate of syllable repetition, and judgments of articulatory defectiveness were measures obtained on 19 dysarthric adults with amyotrophic lateral sclerosis and on 125 normal adults. Anterior and lateral tongue forces were measured by means of a pressure transducer clasped between the teeth; the tongue forces were recorded on a pen-writing ECG apparatus. Audio-recorded syllable repetitions of /p lambda/, /t lambda/, and /k lambda/ also were transcribed on ECG paper and counted. Three listeners rated articulatory precision on a 7-point scale of severity. The normal males had significantly higher tongue forces than normal females; normal subjects had significantly higher tongue forces than dysarthric patients; and anterior tongue forces were significantly greater than lateral in normal and dysarthric patients. There was a high negative correlation between tongue force and severity of articulatory defect. Syllable repetitions were significantly slower in the dysarthric patients than in the normal patients, and a high negative correlation was obtained between syllabic rate and severity of articulatory defect.