Why are some Parkinson disease patients unaware of their dyskinesias?
OBJECTIVE
To test the hypothesis that anosognosia for dyskinesias in Parkinson disease (PD) results from a failure to detect discrepancies between intended and actual movement.


BACKGROUND
PD patients often complain of drug-induced dyskinesias (involuntary movements) less than their carers. This remarkable unawareness is an example of anosognosia (ie, unawareness of deficits associated with an illness). A better understanding of anosognosia for dyskinesias in PD is important to understand the impact of the illness and side effects of treatment.


METHODS
The ability to detect a discrepancy between intended movement and visual feedback about actual movement was investigated in 6 PD patients with anosognosia for dyskinesias, 11 nonanosognosic PD controls with dyskinesias, and 22 healthy volunteers, using a mirror to reverse the expected visual consequences of an executed movement.


RESULTS
Nonanosognosic PD patients and healthy volunteers rated mirror-reversed movement as significantly stranger than normal movement (P=0.024 and <0.001, respectively), whereas PD patients with anosognosia for dyskinesias did not (P=0.375).


CONCLUSIONS
The findings support our proposal, in that PD patients with anosognosia for dyskinesias do not report mirror-reversed movement (in which intentions and visual feedback conflict) as feeling distinct from normal movement.
Jenkinson
Paul M
PM
Psychology and Mental Health, Staffordshire University, UK. p.m.jenkinson@staffs.ac.uk
Edelstyn
Nicola M J
NM
Stephens
Richard
R
Ellis
Simon J
SJ
D000368:Aged; D000978:Antiparkinson Agents / Q000009:adverse effects; D001364:Awareness; D004409:Dyskinesia, Drug-Induced / Q000523:psychology*; D030141:Feedback, Psychological; D005260:Female; D006801:Humans; D007980:Levodopa / Q000009:adverse effects; D008297:Male; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000523:psychology*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D012649:Self Concept
D000978:Antiparkinson Agents; D007980:Levodopa