A high-resolution single photon emission computed tomography study of verbal recognition memory in Alzheimer's disease.
BACKGROUND
In view of the recent technological advances and its ease of availability, we used single photon emission computed tomography (SPECT) to examine the performance of early Alzheimer's disease (AD) subjects on a verbal recognition memory task.


METHODS
Eighteen early AD and 10 matched healthy control subjects underwent split-dose (99m)Tc-HMPAO (Ceretec) SPECT using a verbal recognition memory and control task. SPECT images co-registered with MRI scans were used to determine relative regional cerebral blood flow (rCBF) changes in regions of interest.


RESULTS
In healthy control subjects, verbal recognition increased rCBF in the right occipital region, thalamus, left prefrontal pole, posterior parietal region and cerebellum, and decreased rCBF in the right hippocampus. AD subjects showed bilateral prefrontal, posterior parietal and occipital increases, unilateral increase in the left posterior temporal region, and bilateral reductions in the hippocampus. Although activation was significantly different between the two groups in the right thalamus and left medial prefrontal region, the verbal recognition task did not enhance discrimination between groups.


CONCLUSIONS
Compared with controls, AD subjects activate a similar but more extensive bilateral network during verbal recognition, possibly reflecting an attempt to compensate for impaired processing.
Trollor
Julian N
JN
School of Psychiatry, University of New South Wales, Randwick, Australia. J.Trollor@unsw.edu.au
Sachdev
Perminder S
PS
Haindl
Walter
W
Brodaty
Henry
H
Wen
Wei
W
Walker
Brenda M
BM
D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000473:pathology; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D009778:Occipital Lobe / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D010296:Parietal Lobe / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D017397:Prefrontal Cortex / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D021641:Recognition, Psychology; D012720:Severity of Illness Index; D013067:Speech Perception; D015899:Tomography, Emission-Computed, Single-Photon