The Clock Reading Test: validation of an instrument for the diagnosis of dementia and disorders of visuo-spatial cognition.
BACKGROUND
The 12-item Clock Reading Test (CRT) allows a fine-graded assessment of clock-reading ability. It has a strong focus on visuo-spatial processing and requires no executive processing. This study evaluated the reliability, validity, sensitivity and specificity of the CRT for the diagnosis of dementia and visuo-spatial dysfunction.


METHODS
The CRT, the Clock Drawing Test (CDT) and other tests were applied to groups of 200 subjects with dementia, 105 subjects with mild cognitive impairment (MCI), 20 subjects with focal parietal lesions and 64 elderly control subjects.


RESULTS
The CRT was found to be reliable and sensitive for the detection of cognitive impairment in parietal lesions, Alzheimer-, mixed- and Lewy Body dementia. Normal subjects and patients with MCI, frontotemporal dementia or cerebral small vessel disease showed little or no impairment.


CONCLUSIONS
CRT and CDT are clock-processing tests with different demand profiles. They can supplement each other in the neuropsychological diagnosis of dementia and visuo-spatial dysfunction.
Schmidtke
Klaus
K
Center for Geriatric Medicine and Gerontology Freiburg, University Hospital Freiburg, Germany.
Olbrich
Susanne
S
D000368:Aged; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000175:diagnosis / Q000453:epidemiology*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013028:Space Perception / Q000502:physiology*; D013998:Time Perception; D014796:Visual Perception / Q000502:physiology*