Cerebral substrates related to impaired performance in the clock-drawing test in dementia with Lewy bodies.
OBJECTIVE
To identify the neural correlates of impaired performance in the clock-drawing test (CDT) in patients with dementia with Lewy bodies (DLB).


METHODS
Cerebral blood flow was measured by single photon emission computed tomography in patients with clinically diagnosed DLB, and was compared between impaired CDT (n = 30) and normal CDT (n = 30) subgroups.


RESULTS
DLB patients with impaired CDT performance showed significantly lower cerebral blood flow in the bilateral frontal eye fields, supplementary eye fields, right posterior putamen and the right ventrolateral part of the thalamus relative to the normal CDT subgroup. Performance in other visuospatial/attentional tasks (trail making test part A, copying a cube, semantic fluency, and block design) was also poorer in the impaired CDT group than the normal CDT group.


CONCLUSIONS
This study indicates that impaired performances on the CDT and some visuospatial/attentional tasks by DLB patients are closely related to dysfunctions of the frontal-subcortical network relevant to control of visuospatial attention and arousal, involving the frontal eye fields, supplementary eye fields and the thalamus. Our findings provide evidence that cognitive performance in DLB reflects the pathological involvement of both cortical and subcortical regions, and suggest that the neurophysiological basis underlying impaired CDT in DLB may be different from that in Alzheimer disease.
Nagahama
Yasuhiro
Y
Department of Geriatric Neurology, Shiga Medical Center, Moriyama, Japan. ynaga@pop12.odn.ne.jp
Okina
Tomoko
T
Suzuki
Norio
N
Matsuda
Minoru
M
D000368:Aged; D000369:Aged, 80 and over; D001288:Attention / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D020961:Lewy Body Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D011699:Putamen / Q000000981:diagnostic imaging / Q000503:physiopathology; D013028:Space Perception / Q000502:physiology*; D013788:Thalamus / Q000000981:diagnostic imaging / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon