A physiological analysis of articulatory dysfunction in dysarthric speakers following severe closed-head injury

A physiological analysis of the lip and tongue function of a group of 18 severely closed-head injured (CHI) subjects was performed using lip and tongue force transduction systems. Lip and tongue strength, endurance and rate of repetitive movements were assessed on four non-speech tasks: maximum strength, sustained maximum strength, repetition of 10 maximum strength compressions, and maximum repetition rate. The values recorded were compared to those achieved by a group of 18 non-neurologically impaired subjects, matched for age and sex, who served as the controls. The results of the study indicated that the CHI subjects demonstrated a significant impairment of lip and tongue function based on strength, endurance and rate of repetitive movements, compared to the controls. While lip function was found to be significantly impaired on several measures of strength and endurance, tongue function was noted to be more severely compromised. The CHI subjects were found to exhibit a significantly reduced rate of repetitive movements of the lips and tongue. The results are discussed in relation to the effects of CHI on neuromuscular function and differential subsystem impairment in dysarthria. The clinical implications of these findings are also discussed in relation to the treatment of articulatory disturbances following severe CHI.