- Dementia associated with Parkinson's disease is distinctively
different from that seen in Alzheimer's disease, Norwegian
researchers report in the Journal of Neurology, Neurosurgery and
Psychiatry.
Dr. Kolbjorn Bronnick at Stavanger University Hospital, Norway, and
colleagues conducted a neurological assessment of 488 patients with
Parkinson's disease dementia and another 488 patients with
Alzheimer's disease, using the Mini-Mental State Examination and the
Alzheimer's Disease Assessment Scale-Cognitive Subscale.

The objective of the study by was to assess whether or not a
diagnosis could be made based on the results of the cognitive
profiles.

"Both groups showed memory impairment, Alzheimer's disease patients
performing worse than Parkinson's disease dementia patients," the
investigators report. "On the verbal memory tasks in the Alzheimer's
Disease Assessment Scale-Cognitive Subscale, however, both groups
were clearly impaired relative to a normal control group, with very
large effect sizes."

"Poor performance of the Alzheimer's disease patients on the
orientation test in Alzheimer's Disease Assessment Scale-Cognitive
Subscale best discriminated between the groups, followed by poor
performance of the Parkinson's disease dementia patients on the
attentional task in Mini-Mental State Examination," Bronnick's team
found.

"Diagnosis was predicted from the cognitive profile, with an overall
accuracy of 74.7 percent," they report.

"In conclusion," the researchers write, "we found differential
cognitive profiles in patients with Parkinson's disease dementia and
Alzheimer's disease."

This strongly supports the hypothesis that Parkinson's disease
dementia occurs through a mechanism that is quite different than the
one associated with Alzheimer's disease, and that there exist
pathological and physiological mechanisms specifically related to
Parkinson's disease dementia.

NEW YORK, Oct 2, 2007 (Reuters)