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Necker cube copying may not be appropriate as an examination of dementia: reanalysis from the T ajiri Project
Author(s) -
Oonuma Jiro,
Kasai Mari,
Meguro Mitsue,
Akanuma Kyoko,
Yamaguchi Satoshi,
Meguro Kenichi
Publication year - 2016
Publication title -
psychogeriatrics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.647
H-Index - 32
eISSN - 1479-8301
pISSN - 1346-3500
DOI - 10.1111/psyg.12161
Subject(s) - copying , clinical dementia rating , dementia , psychology , incidence (geometry) , cube (algebra) , medicine , audiology , disease , mathematics , geometry , combinatorics , political science , law
Background The N ecker cube is usually used for evaluating the visuoconstructional ability of patients with mild cognitive impairment ( MCI ) and dementia. However, the N ecker cube is often considered a drawing with a visual illusionary perspective. The purpose of this study was to investigate whether N ecker cube copying could detect participants with MCI due to dementia. Methods We retrospectively analyzed the database of the 1998 prevalence study that was part of the T ajiri P roject ( n = 599). Pencil drawings of the N ecker cube on A 4‐sized white paper by non‐demented people (Clinical Dementia Rating ( CDR ) 0 and 0.5, n = 256) were classified into two patterns: non‐three‐dimension (3‐ D ) and 3‐ D . Two neuropsychologists assessed Necker cube copying according to the criteria of the classification. After the classification, the database of the 2003 incidence study was used according to the subjects’ conversion to dementia. Results In the prevalence study, among those who made a non‐3‐ D drawing of the N ecker cube, there were significantly fewer people in the CDR 0 group than in the CDR 0.5 and CDR 1+ groups; similarly, there were significantly fewer people in the CDR 0.5 group than in the CDR 1 + group (χ 2 = 32.6, P < 0.001; post‐hoc tests using χ 2 tests, CDR 0 > CDR 0.5 > CDR 1+, P < 0.001). In the incidence study, among those who made a non‐3‐ D drawing of the N ecker cube, there were significantly fewer people in the non‐converter group than in the converter group (χ 2 = 19.9, P < 0.001). However, there was no significant difference between the non‐converter group ( n = 21) and the converter group ( n = 21) when age, sex, educational levels, and Mini‐Mental State Examination scores were controlled (χ 2 = 0.0, P = 1.000). Conclusions Our results suggested that N ecker cube copying may evaluate visual illusion as well as visuoconstructional ability. The N ecker cube may not be an appropriate test to detect participants with MCI due to dementia.