Lip function in subjects with upper motor neuron type dysarthria following cerebrovascular accidents

The lip function of 16 speakers with upper motor neuron damage following cerebrovascular accident (CVA), was investigated using instrumental measures. Sixteen, non-neurologically impaired adults matched for age and sex served as controls. The results of the instrumental investigations revealed that the CVA speakers had patterns of lip function that were significantly different from the control speakers. Specifically, on maximum force tasks, the CVA speakers were found to produce significantly lower maximum lip force values. Maximum rate of attempts at lip movement was also slower in the CVA speakers. In addition, the instrumental investigation revealed that the CVA speakers demonstrated a significant decline in pressure over the course of the task involving 10 attempts at maximum lip force. In contrast, the control speakers maintained a consistent level of force throughout the 10 repetitions/attempts. Overall, the findings suggest that the CVA speakers have deficits in maximum lip force, endurance of lip strength and rate of lip movements. Correlations conducted between instrumental measures of maximum lip strength and the perceptual ratings of overall intelligibility, precision of consonants, precision of vowels and length of phonemes revealed no significant relationship.