The reversed clock drawing test phenomenon in Alzheimer's disease: A perfusion SPECT study.
OBJECTIVE
To unveil a brain single photon emission computed tomography (SPECT) pattern in Alzheimer's disease (AD) patients, showing a reversed clock drawing test (CDT) phenomenon.


METHODS
Among 1,005 consecutive subjects, 9 AD patients who drew a reversed CDT (AD-R) underwent SPECT, which was analysed (SPM2) versus a group of 10 AD patients performing the CDT correctly (AD+) and versus 15 controls (CTR). Brain SPECT in 11 AD patients who mistook the CDT in a common way (AD-) was compared with AD+ and CTR groups.


RESULTS
Relative hypoperfusion was found in AD-R versus CTR in right medial frontal, parahippocampal and subcallosal gyri, and in left insula and superior temporal gyrus. Hypoperfusion was found in AD-R versus AD+ in the right uncus, superior temporal and parahippocampal gyri. In the AD- versus CTR comparison, hypoperfusion was found in left hippocampus, parahippocampal gyrus and superior parietal lobule. In AD-R versus AD+ and CTR merged together, the analysis showed hypoperfusion in the right parahippocampus, medial frontal gyrus, superior temporal gyrus and uncus, in the left insula and superior temporal gyrus.


CONCLUSIONS
Fronto-temporal dysfunction, especially in the right hemisphere, plays a role in the reversed CDT phenomenon in AD patients, whereas matched AD patients mistaking the CDT in a common way show left posterior temporo-parietal hypoperfusion.
Brugnolo
A
A
Department of Neuroscience, Ophthalmology and Genetics, University of Genoa, Italy. andrea.brugnolo@fastwebnet.it
Morbelli
S
S
Dessi
B
B
Girtler
N
N
Mazzei
D
D
Famà
F
F
Barbieri
P
P
Cabassi
G
G
Koulibaly
P M
PM
Sambuceti
G
G
Rodriguez
G
G
Nobili
F
F
D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000523:psychology*; D001921:Brain / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation / Q000502:physiology; D003863:Depression / Q000523:psychology; D056344:Executive Function; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D011875:Radionuclide Angiography; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon