Neurophysiological evaluation of the motor performance in patients with Parkinson's disease

Sammanfattning: This study, comprising six separate papers, is concerned with the  description and evaluation of some of the motor disturbances seen in Parkinson patients. Motor performances with different complexity in movement were investigated in patients with ideopathic Parkinson's disease. Muscle contraction characteristics were studied by electrical stimulation of the ulnar nerve and recording of the tension in the adductor pollicis muscle. Voluntary muscle contraction over a "single" joint was tested by concentric and eccentric isokinetic strength measurement including a stretch-shortening cycle. A semiautomatic voluntary movement with important postural components was tested by assessment of basal gait characteristics. Clinical scoring was performed according to Webster and the Hoehn and Y ahr rating scale. The relevance of the tests for evaluation of Parkinson's disease was tested by, a) withdrawal of medication, b) physiotherapeutic training, c) comparison with control subjects of the same age as the patients.The results showed that the contraction and relaxation characteristics of muscle contraction were shorter than in normals, but was not influenced by withdrawal of medication. Isokinetic muscle strength in ankle dorsiflexors in patients were lower in all contractions types andangular velocities, when compared to controls. Strength impainnent was greater in men than women. Strength was influenced by withdrawal of medication. Muscle contraction was performed with a lower efficiency than in nonnals. Muscle stiffness did not seem to impair strength. Gait in patients was disturbed with a shorter stride length and a lower gait velocity than in normals.Gait parameters were further disturbed, when medication was withdrawn. Nonnalization to constant velocity and constant stride duration improved the analyzis. Men were found to be more disabled than women. Gait, but not strength, correlated to the clinical score in group comparisons, but in intraindividual comparisons a correlation between strength and clinical score was found. Gait and strength parameters were not influenced by physical group training. The conclusion of the study was that motor analysis, employing different levels of complexity in motion, can be useful in the description of motor impairment and therapy in Parkinson's disease.