Proprioception in Parkinson's disease is acutely depressed by dopaminergic medications.
OBJECTIVE
Impaired proprioception has been previously reported in patients with Parkinson's disease. It was hypothesised that dopaminergic medications transiently depress proprioception, with amplification of adventitious movements as a result. This study tested for effects on proprioception of dopaminergic drugs, and for associations between such effects and drug induced dyskinesias.


METHODS
In 17 patients with Parkinson's disease, arm proprioception was tested in the practically defined "off" state, and retested 1 hour after taking levodopa or dopamine agonist. Testing consisted of side to side comparison of elbow angle, matching the contralateral elbow angle, and spatial recall of an unrestrained arm.


RESULTS
Proprioception deteriorated as hypothesised, reaching significance by one tailed t test for each of the three tasks. The relative deterioration (and the 95% lower confidence bound for estimated deterioration) was 31% (4%) for side to side elbow comparison, was 27% (11%) for accuracy in matching the contralateral elbow angle, and was 11% (0%) for spatial recall. Dyskinetic (n=6) and non-dyskinetic (n=11) patients did not differ significantly in these effects on proprioception. Control subjects (n=6) and untreated parkinsonian subjects (n=5) did not significantly differ from the parkinsonian patients in the off state.


CONCLUSIONS
Administration of levodopa and dopamine agonists were associated with a modest acute suppression in central responsiveness to joint position. It is speculated that compensatory exaggerated movement could account in part for the phenomenon of drug induced dyskinesias.
O'Suilleabhain
P
P
Department of Neurology, University of Texas, Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9036, USA. Padraig.OSuilleabhain@UTSouthwestern.edu
Bullard
J
J
Dewey
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RB
D000208:Acute Disease; D000328:Adult; D000368:Aged; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000009:adverse effects*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*; D012720:Severity of Illness Index; D020886:Somatosensory Disorders / Q000139:chemically induced* / Q000175:diagnosis
D018491:Dopamine Agonists; D007980:Levodopa