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Cutaneous reflexes in Parkinson's disease
Author(s) -
Fuhr Peter,
Zeffiro Thomas,
Hallett Mark
Publication year - 1992
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880150618
Subject(s) - reflex , inhibitory postsynaptic potential , index finger , excitatory postsynaptic potential , medicine , parkinson's disease , dopaminergic , electrophysiology , electromyography , anesthesia , audiology , neuroscience , anatomy , psychology , physical medicine and rehabilitation , disease , dopamine
The physiology of rigidity in Parkinson's disease (PD) can be investigated by the study of reflexes. Cutaneous reflexes (CR) were measured in 10 patients with PD and in 10 age‐ and sex‐matched normal volunteers. EMG activity was recorded from the first dorsal interosseous muscle with surface electrodes, rectified and averaged. The index finger was stimulated with an intensity four times the sensory threshold. The subjects abducted the index finger with 20% of maximal force. While the latencies of the different reflex components and the amplitudes of the excitatory peaks were not different in the two groups, the first inhibitory components was less pronounced in patients with PD as compared with normals. This effect is partially reversed with dopaminergic drug treatment. The results are compatible with the loss of an inhibitory spinal mechanism elicited by cutaneous afferents, and can be a partial explanation for increased tone in PD.