The Mini-Mental State exam may help in the differentiation of dementia with Lewy bodies and Alzheimer's disease

Abstract

Objective: Since patients with dementia with Lewy bodies (DLB) tend to have greater impairment of attention and construction and better memory ability on neuropsychological tests than patients with Alzheimer's disease (AD), we determined if the items that measure attention, memory, and construction in the Mini-Mental State Examination (MMSE) help to distinguish DLB from AD early in the course of the dementia.

Design: We retrospectively studied the first available MMSE exam for each of our patients with DLB or AD and compared their MMSE subscores for attention, memory, and construction.

Setting: A university dementia brain bank in central Illinois, USA.

Patients: All patients with neuropathologically-proven DLB or AD with MMSE scores > or =13.

Results: We identified 17 DLB and 27 AD patients for whom we had MMSE exams. The attention and construction subtest scores of the DLB group were worse (p=0.0071 and p=0.0038, respectively) than those of the AD group. The memory subscores of the DLB group were better, although the difference did not reach statistical significance (p=0.22). When a mathematical equation was used to combine the three subscores with equal weighting (Attention-5/3Memory+5.Construction), the scores of the DLB group were worse (p=0.00007). Using this equation, a score less than 5 points was associated with DLB with a sensitivity of 0.82 (95% Confidence Interval (CI)=0.57-0.96) and a specificity of 0.81 (95% CI=0.62-0.94).

Conclusions: Our findings support the work of others regarding the relative neuropsychological impairments of DLB and AD and indicate that the MMSE may be helpful in the differentiation of DLB and AD.