Background: Vascular dementia and Alzheimer's disease are the most diffuse forms of dementia. Sometimes, they are difficult to distinguish due to overlaps in symptomatology, pathophysiology, and comorbidity. Visual constructive apraxia is very common in dementia and impairment in these abilities can provide clinical information for differential diagnosis.
Materials and methods: All patients underwent Mini Mental State Examination (MMSE) at basal visit (T0) and after 1 year (T1). We analyzed differences in Qualitative Scoring Method for the Pentagon Copying Test and we explored the visual constructive apraxia evolution in these 2 types of dementia.
Results: In intragroup analysis, we found a significant difference in each group between T0 and T1 in MMSE score (P < .001) and total qualitative scores (P < .001). In intergroup analysis, at T0, we found significance difference in total qualitative scores (P < .001), in numbers of angles (P = .005), in distance/intersection (P < .001), in closure/opening (P = .01), in rotation (P < .001), and in closing-in (P < .001). At T1, we found significance difference in total qualitative scores (P < .001), in particular, in numbers of angles (P < .001), in distance/intersection (P < .001), in closure/opening (P < .001), in rotation (P < .001), and in closing-in (P < .001). The total score showed the highest classification accuracy (.90, 95%CI = .81-0.96) in differentiating patients with Alzheimer's disease from patients with vascular dementia. The optimal threshold value was k = 5. with .84 (95%CI = .69-0.93) sensitivity and .81 (95%CI = .64-0.93) specificity.
Conclusion: Patients with vascular dementia showed more accuracy errors and graphic difficulties than patients with Alzheimer's disease. Qualitative analysis of copy provided a sensitive measure of visual constructive abilities in differentiating dementias, underlining a particularly vulnerability of visuoconstructive functions in vascular dementia compared with Alzheimer's disease.
Keywords: Alzheimer's disease; MMSE; Neuropsychological Evaluation; Visual constructive apraxia; vascular dementia.
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