Effects of visual feedback on manual tracking and action tremor in Parkinson's disease

Xuguang Liu*, Sarah A. Tubbesing, Tipu Z. Aziz, R. Christopher Miall, John F. Stein

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


Visual feedback is one of the key elements in on-line control of smooth manual tracking. To investigate the effects basal ganglia dysfunction have on visual feedback control, we have tested six advanced Parkinson's disease (PD) patients in comparison with normal controls 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. Thus, for the second half of each trial under conditions 2 and 3, no visual feedback of the relationship between the target and the cursor was available. Results showed that although PD patients had significantly larger tracking errors than controls, and errors significantly increased in both PD patients and controls after withdrawing either visual cue, increases in tracking errors in PD were not significantly different from those in controls. Nor were any significant changes found in the frequency (6-8 Hz) or magnitude of the PD patient's action tremor after withdrawing visual feedback. These results suggest that on-line movement control of wrist tracking movements in advanced PD is not especially reliant on visual feedback. In conjunction with our previous study of multiple sclerosis (MS) patients, the present results confirm that the basal ganglia is less involved in visual guidance of smooth manual tracking than the cerebellar circuits.

Original languageEnglish
Pages (from-to)477-481
Number of pages5
JournalExperimental Brain Research
Issue number3
Publication statusPublished - 26 Nov 1999


  • Action tremor
  • Motor control
  • Parkinson's disease
  • Visual feedback

ASJC Scopus subject areas

  • General Neuroscience


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