Effect of pallidotomy on postural control and motor function in Parkinson disease.

OBJECTIVE: To investigate the effects of pallidotomy on postural reactions and other motor parkinsonian deficits. DESIGN: Comparison of performance by patients before and after pallidotomy on tests of balance and function. SETTING: A Parkinson disease Center of Excellence and Center for Human Performance Testing at a university hospital and research center. PARTICIPANTS: Twenty-nine patients with Parkinson disease undergoing pallidotomy. MAIN OUTCOME MEASURES: Performance results on the United Parkinson's Disease Rating Scale (UPDRS), activities of daily living and motor subscales (parts II and III). and posturography (sensory organization test), which were collected before and 3 and 6 months after surgery with patients in the practically defined off state (medication withheld for at least 12 hours). RESULTS: Data were analyzed with a paired Wilcoxon and Spearman correlation. There was a significant improvement in mean +/- SD UPDRS motor subscale score after pallidotomy (before surgery, 52.43+/-13.46; after surgery, 43.93+/-15.15; z= 3.63; P=.003). There were no significant changes in the UPDRS activities of daily living subscale or average stability scores when the group was examined as a whole. However, examination of individual data revealed that 9 (56%) of 16 patients who could stand independently before surgery showed improvement in either the number of falls or the average stability score. No patient who was unable to stand independently before surgery was able to stand independently after it. CONCLUSION: Pallidotomy helped improve overall motor function in patients with parkinsonism and, for some patients, also improved postural stability.

Sensory perception in Parkinson disease.

OBJECTIVE: To determine whether there is a complex sensory disturbance that may be contributing to the motor deficit in patients with Parkinson disease. DESIGN: Comparison of performance by patients and healthy, age- and sex-matched subjects in tests of various sensory functions. SETTING: The Center for Human Performance and Testing at a university hospital and research center. PARTICIPANTS: Ten subjects with Parkinson disease and 10 control subjects matched for age and sex. MAIN OUTCOME MEASURE: Performance on 4 subjects of the Sensory Integration and Praxis Test: finger identification, graphesthesia, localization of tactile stimuli, and kinesthesia. RESULTS: Data were analyzed using paired t tests for ratio data and the paired Wilcoxon test for ordinal data. Patients with Parkinson disease performed significantly worse (P = .001) than the control patients on the test of kinesthesia. There were no significant differences between the 2 groups on the other subtests. CONCLUSIONS: Without visual guidance, patients with Parkinson disease had more difficulty in perceiving the extent of a movement made to a target away from the body, a task requiring reliance on proprioceptive feedback. Parkinsonian patients had no more difficulty than controls in making movements to a target on the surface of the body when they could use tactile sensations. Movement difficulties in patients with Parkinson disease may relate in part to a decrease in proprioception. Activities that enhance kinesthetic awareness may be an important adjunct to the treatment of these patients.

Head-erect behavior among three preschool-aged children with cerebral palsy.

This article presents the results of a multiple baseline design, across subjects, to assess the effect of vibratory stimulation on head-erect behavior in subjects who were prone. The subjects were three children with severe multiple handicaps whose mean age was 2 years 4 months and whose conditions included seizures and muscle tone disorders. Frequency of head lifts and cumulative duration of head-erect behavior were recorded during three-minute sessions with the subjects positioned prone on their forearms over a wedge. After baseline observations were recorded, vibration was applied to the paraspinal muscles of the neck and upper back for the first two minutes of each intervention session. In addition, electromyographic activity was recorded for a three-minute session at least once during both the baseline and intervention conditions. Results of the study demonstrated an increase in the cumulative duration of head-erect behavior for the three subjects and an accompanying increase in EMG activity during muscle vibration. The diversity of handicapping conditions (ie, seizures, hypertonia, and hypotonia) appeared to have no effect on the benefits received from muscle vibration for these subjects. Limitations of the study and implications for future research are discussed.

Activity of forebrain neurons during alternating movements in cats.

The firing pattern of single units in the precruciate cortex, globus pallidus, entopeduncular nucleus and ventral thalamus of cats was studied before alternating limb movements. Seventy-eight percent of the neurons in these regions of the brain changed their activity more than 500 msec before the movement. No consistent early EMG changes occurred in the proximal or axial muscles which would correlate with the early neuronal activity changes. The data suggest that the sequence of movements required for this alternation task appears to be 'set' well in advance of the activation of the muscles involved in the necessary postural adjustments or the response itself. In addition, the units which showed early activity changes may be involved in the mnemonic processing necessary to discriminate a situational context and make an appropriate response. Over 50% of the movement related units in the globus pallidus, entopeduncular nucleus and ventral thalamus were related to movement of both the contralateral and ipsilateral paws. By contrast, only 33% of cortical units showed this relationship to the movement. Therefore, this 'set' process may be a relatively non-lateralized process. The data support the concept that the basal ganglia are involved in the enabling and sequencing of movements rather than in directly causing them to occur.

An adaptable, multiple plate dynamometer and electromyograph for the study of quadruped postural responses.

An EMG-force measurement system which can be placed inside a sound dampened testing chamber to study subtle postural responses in the standing quadruped is described. The dynamometer is adjustable to accommodate different foot placement strategies and to afford a more natural standing posture. A non-telemeterized method of recording EMG from an unrestrained animal is also discussed.