[A study on truncal rigidity in parkinsonism--evaluation of diagnostic test and electrophysiological study]

Truncal rigidity is regarded as a cause of axial motor disturbances such as difficulty in turning around and in rising from a recumbent position in parkinsonism. However, methodology for clinical evaluation of truncal rigidity has not yet been established. This study aims at developing a suitable bed-side technique to evaluate truncal rigidity in parkinsonism. Forty normal adults and fifty-one patients with Parkinson's disease or juvenile parkinsonism were examined. We tried to evaluate truncal tonus by twisting the subjects' body axis in a supine position. The subjects' axis was passively rotated by the examiner supporting and twisting the subjects' (1) shoulder, (2) axillas, (3) hips, and (4) knees. In comparing these four procedures, the maximal rotation of the axis was obtained easily with twists supporting the knees, that is alternating tilts of the bending knees rightward and leftward in a supine position. By this method of alternating knee tilts, the examiner felt merely a little resistance in twisting the normal subjects. On the other hand, in patients with parkinsonism, a considerable degree of resistance against twists was elicited, and the patients' side-was passively elevated from a bed in accordance with knee tilts. Electrical activities of the truncal muscles (M. erector spinae, M. obliquus abdominis externus and internus) during the alternating knee tilts were studied in ten normal adults and seventeen parkinsonian patients. Continuous electrical activities were present in the axial muscles, particularly at the thoracic level, which were passively stretched by this procedure in parkinsonism but never present in normals.(ABSTRACT TRUNCATED AT 250 WORDS)