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  • Author: Bruce E. Murdoch x
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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.

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Bruce E. Murdoch, Tracey J. Spencer, Deborah G. Theodoros and Elizabeth C. Thompson

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.

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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.

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Joanne E. Folker, Bruce E. Murdoch, Louise M. Cahill, Kristin M. Rosen, Martin B. Delatycki, Louise A. Corben and Adam P. Vogel

Electropalatography (EPG) was used to describe the pattern of linguopalatal contact and the consonant phase durations exhibited by a group of seven individuals with dysarthria associated with Friedreich’s ataxia (FRDA). A group of 14 non-neurologically impaired individuals served as controls. The Reading Electropalatograph (EPG3) system was used to record linguopalatal contact during production of the target consonants (/t/, /l/, /s/, /k/) elicited in five words of CV and CVC construction, with the target consonants in word initial position. These words were embedded into short sentences and repeated five times by each participant. The FRDA group exhibited significantly increased consonant durations compared with the controls while maintaining normal linguopalatal contact patterns. These findings suggest that the articulatory impairment in FRDA manifests as a temporal rather than spatial disturbance.

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Joanne E. Folker, Bruce E. Murdoch, Louise M. Cahill, Kristin M. Rosen, Martin B. Delatycki, Louise A. Corben and Adam P. Vogel

Electromagnetic articulography (EMA) was used to investigate the tongue kinematics in the dysarthria associated with Friedreich’s ataxia (FRDA). The subject group consisted of four individuals diagnosed with FRDA. Five nonneurologically impaired individuals, matched for age and gender, served as controls. Each participant was assessed using the AG-200 EMA system during six repetitions of the tongue tip sentence Tess told Dan to stay fit and the tongue back sentence Karl got a croaking frog. Results revealed reduced speed measures (i.e., maximum acceleration / deceleration / velocity), greater movement durations and increased articulatory distances for the approach phases of consonant productions. The approach phase, involving movement up to the palate, was more affected than the release phase. It is suggested that deviant lingual kinematics could be the outcome of disturbances to cerebellar function, or possibly in combination with disturbances to upper motor neuron systems.