Cortical cholinergic function is more severely affected in parkinsonian dementia than in Alzheimer disease: an in vivo positron emission tomographic study.
BACKGROUND
Pathology reports have shown that cholinergic forebrain neuronal losses in parkinsonian dementia (PDem) are equal to or greater than those in Alzheimer disease (AD). We hypothesized that patients with PDem would have cholinergic deficits that were similar to or greater than those of patients with AD.


OBJECTIVE
To determine in vivo cortical acetylcholinesterase (AChE) activity in healthy control subjects and in patients with mild AD, PDem, and Parkinson disease without dementia using AChE positron emission tomography.


METHODS
University and Veterans' Administration medical center. Design and Patients Group comparison design of patients with AD (n = 12), PDem (n = 14), and Parkinson disease without dementia (n = 11), and controls (n = 10) who underwent AChE imaging between July 1, 2000, and January 31, 2003. Patients with AD and PDem had approximately equal dementia severity.


METHODS
Cerebral AChE activity.


RESULTS
Compared with controls, mean cortical AChE activity was lowest in patients with PDem (-20.0%), followed by patients with Parkinson disease without dementia (-12.9%; P<.001). Mean cortical AChE activity was relatively preserved in patients with AD (-9.1%), except for regionally selective involvement of the lateral temporal cortex (-15%; P<.001).


CONCLUSIONS
Reduced cortical AChE activity is more characteristic of patients with PDem than of patients with mild AD.
Bohnen
Nicolaas I
NI
Departments of Neurology and Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
Kaufer
Daniel I
DI
Ivanco
Larry S
LS
Lopresti
Brian
B
Koeppe
Robert A
RA
Davis
James G
JG
Mathis
Chester A
CA
Moore
Robert Y
RY
DeKosky
Steven T
ST
D000110:Acetylcholinesterase / Q000378:metabolism*; D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000201:enzymology*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000201:enzymology*; D003704:Dementia / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D010300:Parkinson Disease / Q000150:complications* / Q000000981:diagnostic imaging / Q000201:enzymology*; D014055:Tomography, Emission-Computed
D000110:Acetylcholinesterase