ORIGINAL ARTICLE: Computerized visuo‐spatial memory test as a supplementary screening test for dementia

Background: To prepare for a super‐aging society, effective dementia screening tests are required. The most salient deficit appearing from the early stages of dementia/Alzheimer's disease (AD) is a deterioration in memory. The Hasegawa Dementia Scale‐revised (HDS‐R) and the Mini‐Mental State Examination (MMSE) are widely used in Japan to screen for dementia. Both place an emphasis on memory function, but neither examines visuo‐spatial memory (VSM) function, even though VSM deficits are a sensitive marker for the detection of conversion to dementia. Furthermore, brief tests of VSM that are appropriate for screening have not been standardized. Thus, in the present study, we devised a brief, computer‐aided short‐term VSM test. Methods: Sixty‐six aged people were evaluated. Using the Clinical Dementia Rating (CDR), it was found that 29 could be considered normal controls (NC; CDR 0), 10 had mild cognitive impairment (MCI; CDR 0.5), 15 had mild dementia (CDR 1), and 12 had moderate to severe dementia (CDR 2–3). The VSM test estimated how many locations each subject could memorize. Several numbered circles were shown on a monitor and subjects were required to memorize the location of these circles sequentially. After the numbers on the circles on the screen had disappeared, the subjects were required to indicate the circles in ascending order. A touch panel screen was used for this test to make it easier. The HDS‐R was applied to subjects with MCI and dementia. Results: The mean (±SD) VSM score in subjects with MCI (5.70 ± 0.96) was significantly lower than that in NC subjects (6.69 ± 0.82), but significantly higher than that in subjects classified as CDR 1 (4.67 ± 0.87). There was no significant difference in VSM scores between subjects classified as CDR 1 and CDR 2–3 (3.80 ± 0.80). There was a moderate significant correlation between VSM and HDS‐R scores. Conclusion: In the present study, the VSM test detected differences in VSM function among NC subjects and subjects with MCI and mild dementia. The software program for the VSM test is distributed for free so that it can be widely used.