"Closing-in" phenomenon in Alzheimer's disease and subcortical vascular dementia.
BACKGROUND
The 'closing-in' phenomenon is defined as a tendency to close in on a model while copying it. This is one of several constructional apraxia observed in dementia, particularly in Alzheimer's disease (AD). The aim of this study was to investigate the usefulness of it in the differential diagnosis of AD and subcortical vascular dementia (SVD) and to clarify the factors associated with it.


METHODS
We operationally defined and classified it into three types, namely overlap, adherent, and near type. We analyzed the incidence of it in patients with AD (n = 98) and SVD (n = 48).


RESULTS
AD patients exhibited a significantly higher occurrence of it as compared to SVD patients. Among the different types of it, the overlap and adherent types occurred almost exclusively in AD patients. A discriminant analysis in AD subjects revealed that the scores obtained from the MMSE, CDR, Barthel index, and the Rey-Osterrieth complex figure test were correlated significantly with the occurrence of it. There was no statistical difference between the Q-EEG parameters of patients that exhibited the closing-in phenomenon and those that did not.


CONCLUSIONS
This study suggests that the closing-in phenomenon is phase- and AD-specific and might be a useful tool for the differential diagnosis of AD and SVD.
Kwak
Yong Tae
YT
Department of Neurology, Hyoja Geriatric Hospital, Sangha-ri 33, Kuseong-myeon, Yongin-shi Kyunggki-do, 449-910, Korea. ytkwak@drkwak.com
D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis*; D001072:Apraxias / Q000175:diagnosis* / Q000209:etiology; D015140:Dementia, Vascular / Q000175:diagnosis*; D003937:Diagnosis, Differential; D016002:Discriminant Analysis; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011237:Predictive Value of Tests; D012016:Reference Values; D012680:Sensitivity and Specificity