A functional neuroimaging study of appetite loss in Alzheimer's disease.
BACKGROUND
Alzheimer's Disease (AD) is frequently associated with changes in appetite. This study investigated the relationship between regional cerebral perfusion and appetite loss in AD.


METHODS
64 patients with possible or probable AD were characterized as being with (n=22) or without (n=44) appetite loss based on the Neuropsychiatric Inventory (NPI) Appetite subscale. 99mTc-ECD SPECT scans were coregistered to a standardized template in Talairach space generating mean ratios of uptake referenced to the cerebellum. Regions of interest (ROIs) included anterior cingulate cortex (ACC), middle mesial temporal cortex (MTC-m), inferior mesial temporal cortex (MTC-i), insula (INS), orbitofrontal cortex (OFC) and thalamus-hypothalamus (THAL).


RESULTS
Backward stepwise logistic regression analysis of these ROIs showed hypoperfusion in the L-ACC (p=0.015) and L-OFC (p=0.015), relative sparing of perfusion in the R-ACC (p=0.010), R-OFC (p=0.010) and L-MTC-m (p=0.006), and greater anxiety (p=0.005) independently predicted loss of appetite (chi(2)=22.24, p=0.001, Nagelkerke R(2)=0.41).


CONCLUSIONS
Hypoperfusion in the left anterior cingulate and left orbitofrontal cortices, and relative sparing of perfusion in the right anterior cingulate, right orbitofrontal and left middle mesial temporal cortices emerged as predictors of appetite loss in this sample of patients. These findings are consistent with impairments in the extrinsic motivational pathways of eating and impaired reward value of food as components of appetite loss in AD.
Ismail
Zahinoor
Z
Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Herrmann
Nathan
N
Rothenburg
Lana S
LS
Cotter
Adolfo
A
Leibovitch
Farrell S
FS
Rafi-Tari
Shahryar
S
Black
Sandra E
SE
Lanctôt
Krista L
KL
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications* / Q000000981:diagnostic imaging*; D000855:Anorexia / Q000000981:diagnostic imaging* / Q000209:etiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon