Objective: To investigate the risk and the content of visual hallucination (VH) among patients with Lewy body dementia (LBD) within the cultural background of Taiwan.

Background: Many LBD patients experience VH in either simple (e.g. feeling of presence, shadows, patterns) or complex (e.g. people, animals, objects) form. The content of VH is known to be influenced by individual cultural background; however, it is sometimes mistaken as a crazy idea rather than a dementia feature. To characterize VH is key to better public education and early diagnosis for LBD.

Method: This is a cross-sectional study. We enrolled patients with LBD, including dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PD-D), aged 50 to 90 years, from a memory clinic in Hualien Tzu Chi Hospital during the entire year of 2023. We described the demographic and clinical features of LBD with VH, together with the content reported by the patients. The data were analyzed using multivariable logistic regression models.

Results: A total of 67 patients (DLB, n=36; PD-D, n=31) were enrolled with a mean age at 81.4 years (M: F = 34: 33). Nearly 80% of LBD experienced VH [table 1], and the development of VH was associated with lower cognitive performance in mini-mental state exam and REM sleep behavioral disorders (OR = 6.05, p = 0.047) [table 2]. Patients with LBD developed VH predominantly in complex form (86.5%) [figure 1]. Twenty-five patients (37%) developed more than one type of VH, and the most common complex VH was people (64%), followed by insects (30%), animals (18%) and mythical figures (7%) [figure 2]. The hallucinated people were often adults (61%), followed by children (33%) and infants (5.5%). The most common hallucinated insects were ants (52.9%), followed by mosquitoes (11.7%), cockroaches (11.7%), and spiders (5.8%). Regarding animals, the most common were dogs (26.6%), followed by snakes (17.6%), birds (11.7%), cats (11.7%), chickens, cows, pigs, and frogs. Among mythical creatures, the most frequently seen were miniature people (42.8%), followed by ghosts (28.6%) and folk deities (28.6%). PD-D patients were more likely to develop hallucinated insects [figure 3].

Conclusion: VH is associated with lower cognitive function and RBD. Within the background of Taiwan, the most common hallucinated figures are adults, ants, and dogs in their respective categories, suggesting cultural context may play a role in the content of VH among patients with LBD.

table 1

table 2

figure 1. Distribution of visual hallucination.

figure 2. Contents of visual hallucination.

figure 3. Visual hallucination in LBD subtypes.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/characteristics-of-visual-hallucinations-in-lewy-body-dementia/