A specific shifting deficit in Parkinson's disease: a reversal shift of consistent stimulus-response mappings.
Two experiments were designed to investigate effects of cueing upon aptitude for shifting by patients with Parkinson's disease. Subjects executed in alternation two different components of a task set over successive items in a list. We compared the costs of shifting when the stimulus ensemble remained constant from trial to trial ("uniform" lists), with the case in which a change of stimulus ensemble cued each shift of task ("mixed" lists). Shift costs with mixed lists were significantly smaller than those with uniform lists (Exp. 1, ns = 12). This suggests that patients with Parkinson's disease can benefit from cues about the stimulus ensemble in performing tasks. Patients' shifting performance was different from that of controls only in a reversal-shift condition of the previously consistent stimulus-response mappings (Exp. 2, ns = 12). This result suggests that patients with Parkinson's disease suffer from a specific but not a general deficit in ability to shift.
Hsieh
S
S
Department of Psychology, National Chung Cheng University, Taiwan, R.O.C. psyhsl@ccunix.ccu.edu.tw
Chuang
Y Y
YY
Hwang
W J
WJ
Pai
M C
MC
D001479:Basal Ganglia / Q000502:physiology / Q000503:physiopathology; D003071:Cognition / Q000502:physiology; D003463:Cues; D005260:Female; D005625:Frontal Lobe / Q000502:physiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014796:Visual Perception / Q000502:physiology