Visuospatial planning and problem solving in Alzheimer's disease patients: a study with the Tower of London Test.
BACKGROUND
Executive dysfunction in Alzheimer's disease (AD) has been recently recognized as an early and prominent clinical sign. The Tower of London (ToL), a task specifically devised to test executive functions of visuospatial planning and problem solving, has frequently been used in neuropsychological experiments, but rarely in the clinical ground.


METHODS
One hundred and sixty-one AD patients and 212 nondemented healthy controls were administered a simplified ToL version.


RESULTS
AD patients were significantly impaired (p < 0.0001) in all ToL scores and in the total execution time. The 'accuracy' score of ToL at a cut off of <or=29/36 yielded a sensitivity of 71.2% and a specificity of 76.4% (AUC 0.79) for the diagnosis of AD versus controls.


CONCLUSIONS
Visuospatial planning and problem solving are significantly impaired in early dementia of the Alzheimer's type. A successful sensitivity/specificity ratio, the independence of education and the simplicity of this version of ToL make it a useful executive functioning screening test for early AD.
Franceschi
Massimo
M
Neurology Department, IRCCS Multimedica, Castellanza, Italy. massimo.franceschi@multimedica.it
Caffarra
Paolo
P
De Vreese
Luc
L
Pelati
Oriana
O
Pradelli
Samantha
S
Savarè
Rita
R
Cerutti
Renata
R
Grossi
Enzo
E
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D015995:Prevalence; D012720:Severity of Illness Index; D013028:Space Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*