Clinical Manifestations.

Background: Prodromal dementia with Lewy bodies (DLB) research criteria were recently published and further work is needed to characterize the neuropsychological profile and refine clinical criteria. We performed a meta-analysis to compare the cognitive performance of mild cognitive impairment with Lewy bodies (MCI-LB) groups to controls, MCI due to Alzheimer's disease (MCI-AD), and DLB.

Method: Following PRISMA guidelines, we searched the literature for 1) English-language studies on MCI-LB; 2) published January 1990-March 2023, 3) with ≥1 standardized cognitive measure; and 4) comparison data from controls, MCI-AD, and/or DLB. Pooled means with 95% confidence intervals were calculated for demographics. Effect sizes were calculated for group comparisons on cognitive domains. Random effects meta-analysis models were used for group comparisons.

Result: There were 3440 participants from 27 studies across 10 countries. Mean age did not differ between groups. The percentage of female subjects was lower in the MCI-LB group than the MCI-AD group. Mean years of education for the MCI-LB group was lower than the controls, but similar to MCI-AD and DLB groups (Table 1). Compared to controls, the MCI-LB group had lower scores for the global screening, executive function, visuospatial, language, learning, and memory domains. Compared to MCI-AD, MCI-LB performed better on learning and delayed recall, but similarly across other domains. Compared to DLB, MCI-LB had better scores for global screening, executive function, language, and delayed recall (Table 2). Recognition for MCI-LB vs. MCI-AD; visuospatial, learning, and recognition for MCI-LB vs. DLB could not be assessed, as fewer than 3 studies reported this data.

Conclusion: Cognitive measures can help differentiate MCI-LB from controls and DLB. Neuropsychological measures of learning and memory may be required to discriminate MCI-LB from MCI-AD in clinical practice but global screening measure scores appear insufficient in this regard. High heterogeneity across MCI-LB studies highlights the need for harmonized neuropsychological research protocols.