title: Increased response to visual feedback of drug-induced dyskinetic movements in advanced Parkinson's disease.
abstract: To investigate the response to visual feedback of involuntary movements which have a frequency composition similar to cerebellar tremor but are not caused by cerebellar damage, we have tested six advanced Parkinson's disease (PD) patients with drug-induced dyskinetic movements using visually guided wrist tracking tasks. Tracking performance was assessed under three visual conditions: (1) both guiding target and movement cursor were displayed continuously; (2) the target display was turned off for the second half of each trial; or (3) the cursor display, but not the target, was turned off for the second half of each trial. The response to visual feedback of drug-induced dyskinetic movements at 1-5 Hz in these advanced PD patients were significantly increased than in normal controls. This suggests that increased response to visual feedback might be a common feature of low frequency involuntary movements and not directly caused by cerebellar damages.
authors.affiliation: University Laboratory of Physiology, Parks Road, OX1 3PT, Oxford, UK. xl@physiol.ox.ac.uk
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Osterbauer
authors.forename: T Z
authors.initials: TZ
authors.lastname: Aziz
authors.forename: R C
authors.initials: RC
authors.lastname: Miall
authors.forename: J F
authors.initials: JF
authors.lastname: Stein
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001676:Biofeedback, Psychology / Q000502:physiology*; D003463:Cues; D004409:Dyskinesia, Drug-Induced / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000523:psychology; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*