Treatment effects of therapeutic cholinesterase inhibitors on visuospatial processing in Alzheimer's disease: a longitudinal functional MRI study.
OBJECTIVE
Visuospatial impairments are known to occur in Alzheimer's disease (AD). We hypothesised that functional magnetic resonance imaging (fMRI) response in task-related brain regions would be impaired in patients with AD during the task and that treatment with acetyl cholinesterase inhibitors would enhance activations in brain regions concerned with this visual perceptual processing.


METHODS
Ten AD subjects were neuropsychologically assessed and underwent fMRI imaging whilst performing a series of visuospatial perception tasks, before and after treatment with acetyl cholinesterase inhibitors. Eleven healthy elderly comparison subjects were also scanned twice.


RESULTS
Regions of increased brain activation in AD included the left precuneus, left cuneus, left supramarginal gyrus, right parieto-temporal cortex and right inferior parietal lobule. Further, increased activation in the left precuneus was found to correlate significantly with improved functioning of activities of daily living.


CONCLUSIONS
We believe this to be the first fMRI study that, after controlling for the confound of repeat scanning, demonstrates altered patterns of brain activation associated with visuospatial processing following treatment in patients with AD. The treatment-related improvement of visual perception in AD may rely on enhanced attentional mechanisms, thereby possibly supporting independent living through improvement on activities of daily living.
Thiyagesh
Subha N
SN
Sheffield Cognition and Neuroimaging Laboratory (SCANLab), Academic Clinical Psychiatry, University of Sheffield, The Longley Centre, Sheffield, UK. s.thiyagesh@sheffield.ac.uk
Farrow
Tom F D
TF
Parks
Randolph W
RW
Accosta-Mesa
Hector
H
Hunter
Michael D
MD
Young
Claire
C
Wilkinson
Iain D
ID
Woodruff
Peter W R
PW
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000188:drug therapy* / Q000473:pathology / Q000523:psychology*; D002540:Cerebral Cortex / Q000473:pathology; D002800:Cholinesterase Inhibitors / Q000627:therapeutic use*; D003627:Data Interpretation, Statistical; D018450:Disease Progression; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D009039:Motion Perception / Q000502:physiology; D009044:Motor Cortex / Q000473:pathology; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010296:Parietal Lobe / Q000473:pathology; D010775:Photic Stimulation; D013028:Space Perception / Q000187:drug effects*; D016896:Treatment Outcome; D014796:Visual Perception / Q000187:drug effects*
D002800:Cholinesterase Inhibitors; D010100:Oxygen