Cerebral correlates of psychotic symptoms in Alzheimer's disease.
BACKGROUND
Psychotic symptoms are produced by distributed neuronal dysfunction. Abnormalities of reality testing and false inference implicate frontal lobe abnormalities.


OBJECTIVE
To identify the functional imaging profile of patients with Alzheimer's disease manifesting psychotic symptoms as measured by single photon emission computed tomography (SPECT).


METHODS
Twenty patients with Alzheimer's disease who had SPECT and clinical evaluations were divided into two equal groups with similar mini mental status examination (MMSE), age, sex, and the range of behaviours documented by the neuropsychiatric inventory (NPI), except delusions and hallucinations. SPECT studies, registered to a probabilistic anatomical atlas, were normalised across the combined group mean intensity level, and subjected to a voxel by voxel subtraction of the non-psychotic minus psychotic groups. Subvolume thresholding (SVT) corrected random lobar noise to produce a three dimensional functional significance map.


RESULTS
The significance map showed lower regional perfusion in the right and left dorsolateral frontal, left anterior cingulate, and left ventral striatal regions along with the left pulvinar and dorsolateral parietal cortex, in the psychotic versus non-psychotic group.


CONCLUSIONS
Patients with Alzheimer's disease who manifest psychosis may have disproportionate dysfunction of frontal lobes and related subcortical and parietal structures.
Mega
M S
MS
Department of Neurology UCLA School of Medicine, UCLA School of Medicine, Los Angeles, California, USA. mega@loni.ucla.edu
Lee
L
L
Dinov
I D
ID
Mishkin
F
F
Toga
A W
AW
Cummings
J L
JL
D000544:Alzheimer Disease / Q000150:complications* / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D003342:Corpus Striatum / Q000098:blood supply / Q000000981:diagnostic imaging; D003702:Delusions / Q000209:etiology; D005260:Female; D005625:Frontal Lobe / Q000098:blood supply / Q000000981:diagnostic imaging; D006179:Gyrus Cinguli / Q000098:blood supply / Q000000981:diagnostic imaging; D006212:Hallucinations / Q000209:etiology; D006801:Humans; D008297:Male; D010296:Parietal Lobe / Q000098:blood supply / Q000000981:diagnostic imaging; D011618:Psychotic Disorders / Q000000981:diagnostic imaging / Q000209:etiology*; D012737:Sex Factors; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon
D019690:Technetium Tc 99m Exametazime