A physiological analysis of the articulatory function of 16 adults with multiple sclerosis (MS) was performed using lip and tongue transduction systems. Sixteen nonneurologically impaired adults, matched for age, gender, and education, served as controls. The MS speakers demonstrated patterns of tongue function that were significantly different from those of the control speakers. Specifically, the MS speakers had significantly reduced tongue strength, endurance, and rate of repetitive movements. In addition, preclinical signs of lingual dysfunction were evident in nondysarthric MS speakers on endurance and rate tasks when compared to control subjects. These physiological findings could account for the perceptual findings of impaired articulation and reduced intelligibility. No lip dysfunction was revealed through either the physiological or the perceptual assessments.
Bruce E. Murdoch, Tracey J. Spencer, Deborah G. Theodoros, and Elizabeth C. Thompson
Kirrie J. Ballard, Heather D. Smith, Divija Paramatmuni, Patricia McCabe, Deborah G. Theodoros, and Bruce E. Murdoch
Knowledge of Performance (KP) feedback, such as biofeedback or kinematic feedback, is used to provide information on the nature and quality of movement responses for the purpose of guiding active learning or rehabilitation of motor skills. It has been proposed that KP feedback may interfere with long-term learning when provided throughout training. Here, twelve healthy English-speaking adults were trained to produce a trilled Russian [r] in words with KP kinematic feedback using electropalatography (EPG) and without KP (noKP). Five one-hour training sessions were provided over one week with testing pretraining and one day and one week posttraining. No group differences were found at pretraining or one day post training for production accuracy. A group by time interaction supported the hypothesis that providing kinematic feedback continually during skill acquisition interferes with retention.
Louise M. Cahill, Bruce E. Murdoch, Deborah G. Theodoros, Edward J. Triggs, Bruce G. Charles, and Amy A. Yao
To quantify lip function in 16 subjects with Parkinson's disease, a computerized semiconductor lip pressure transducer system was used prior to subjects being administered oral levodopa and at approximately 0.5 hr, 1.5 hr, and 3.0 hr postmedication. Two blood samples were taken from each subject at varying times during the levodopa dosage interval, and the exact time and dosage of levodopa were noted. Lip function measurements were expressed as percentage changes from baseline and were plotted for each subject against time and levodopa concentrations to determine the effects of levodopa therapy on articulatory function. The results supported the effectiveness of levodopa therapy in improving lip function. In particular, lip pressures recorded during both speech and nonspeech tasks tended to improve after levodopa administration, the lip measures improving somewhat in parallel with the rise and fall of blood plasma levodopa concentrations. Evidence of a hysteresis effect was noted.