POSTURAL FINGER TREMOR EXHIBITED BY PARKINSON PATIENTS AND AGE-MATCHED SUBJECTS

Physiological correlates of postural tremor of the finger seen in Park inson's disease patients are different from those seen in age-matched control subjects, A significant correlation between the spectral peak of acceleration and the spectral peak of rectified electromyographic a ctivity from the muscle responsible for finger extension was found in Parkinson's disease patients, This correlation was not seen in age-mat ched control subjects. Any neural drive imposed on the motoneuron pool from supraspinal levels would enhance the electromyographic activity. Likewise, any feedback effects via spinal stretch reflexes or suprasp inal stretch responses would be mediated through the motoneuron pool a nd electromyographic activity. The results of this research support th e theory that Parkinson tremor is a centrally driven rhythm that may b e influenced by feedback effects, whereas physiological tremor is due to a complex interaction of central, feedback, and mechanical effects.