Disturbed visuo-spatial orientation in the early stage of Alzheimer's dementia

A pilot study was conducted to assess previously unrecognized visuo-spatial disturbances in 45 Alzheimer's demented (AD) patients and 59 control persons all over the age of 65 years, living in the community. The results of the Clock Drawing Test (CDT) revealed high frequency (78%) of deficient performative visuo-spatial skills of mild and moderate demented AD patients. The severity of dementia was found to be a good predictor of the deficit in visuoconstructive performance. The most frequent drawing mistakes were the misplacement of numbers and clock hands, which may relate to dysfunctions of the right inferior parietal cortex. The right-left orientation (RLO) for the own body was not deteriorated in AD patients. However, significantly lower scores for RLO in the mental rotation subtest were found in mild and moderate AD groups. There were large inter-individual differences in the test scores of both demented groups. Thirty-one percent and 49% of the AD patients scored 0 points or within the normal range (more than 4 points), respectively, indicating a pseudofocal onset pattern of the dementia. The results of the CDT and Right-Left Orientation Test (RLOT) with Mental rotation showed significant positive correlation with other cognitive functions of Mini Mental State Exam, such as attention-calculation, recall and writing, and indicate that the visuo-spatial orientation (VSO) is a composite of different cognitive skills. The CDT and RLOT appears to be a useful tool for screening the elderly for disturbed VSO.