HOW CONVINCING IS THE EVIDENCE FOR COGNITIVE SLOWING IN PARKINSONS-DISEASE

The issue of whether or not Parkinson's disease (PD) patients process information more slowly than normal is unresolved. Across a range of p aradigms the evidence for slowing is scant, and many show no slowing. Even the results of a single experimental paradigm can be conflicting; some studies have obtained evidence for slowed memory scanning in sub groups of PD patients whereas others have not. The present study sough t the cause of these discrepant results. Old-old (n=11) and young-old (n=7) PD subjects and controls (n=16, n=9) completed both fixed and va ried set versions of the memory scanning task. No evidence for slowing in PD was found. These results indicated that PD did not interact wit h age or task version in its effects on information processing rates i n the memory scanning task. It was concluded that PD patients do not h ave any cognitive slowing that is detectable with the memory scanning task.