Department of Neuroscience, Medical School, University of Sheffield, Sheffield, UK.
Department of Neurosciences, University of Padua, Padua, Italy.
Cortex. 2021 Sep;142:74-83. doi: 10.1016/j.cortex.2021.05.018. Epub 2021 Jun 9.
Visual hallucinations (VH) are common in dementia with Lewy bodies (DLB), and are among the core symptoms for its clinical diagnosis. VH have been associated with cognitive alterations, although research findings in this area are still limited. The present study aimed at investigating the cognitive correlates of VH in DLB, and the baseline neuropsychological features predicting the future development of VH. A cross sectional study compared the cognitive profile of 18 DLB patients with VH with that of 32 DLB without VH. A longitudinal study involved 34 DLB patients with no VH at baseline, among whom 17 developed VH and 17 remained without VH at follow-up. Logistic regression analyses were carried out to investigate what baseline cognitive variables independently predicted the development of VH at follow-up. DLB patients with VH had worse performance on the copy of the Rey complex figure, assessing visual construction/perception, than those without VH in the cross-sectional study (p = .001). Significant impairments in attention and visual memory delayed recall were also present. Baseline performance on the immediate prose memory was the only significant predictor of VH development in the longitudinal study (p = .03). DLB patients are more at risk of developing VH if presenting more severe immediate verbal memory impairment, and this might be related to a combination of (a) DMN-related dysfunctions, (b) impairment in medial temporal lobe-related functions, and (c) frontal abilities including long-term encoding of information and working memory. Differences between hallucinating and non-hallucinating patients in visual construction/perception, typical of DLB symptomatology, may be essential for VH to emerge in individuals with an at risk cognitive profile.
视幻觉（VH）在路易体痴呆（DLB）中很常见，是其临床诊断的核心症状之一。VH 与认知改变有关，但该领域的研究结果仍有限。本研究旨在探讨 DLB 中 VH 的认知相关性，以及预测 VH 未来发展的基线神经心理学特征。一项横断面研究比较了 18 例有 VH 的 DLB 患者和 32 例无 VH 的 DLB 患者的认知特征。一项纵向研究涉及 34 例基线时无 VH 的 DLB 患者，其中 17 例出现 VH，17 例在随访时仍无 VH。进行逻辑回归分析，以探讨哪些基线认知变量独立预测随访时 VH 的发展。在横断面研究中，有 VH 的 DLB 患者在复制 Rey 复杂图形（评估视觉结构/感知）方面的表现比无 VH 的患者差（p=0.001）。注意力和视觉记忆延迟回忆也存在显著损伤。在纵向研究中，基线即时散文记忆的表现是 VH 发展的唯一显著预测因子（p=0.03）。如果 DLB 患者表现出更严重的即时言语记忆损伤，他们更有可能发展为 VH，这可能与（a）DMN 相关功能障碍、（b）内侧颞叶相关功能障碍和（c）包括信息长期编码和工作记忆在内的额叶能力的组合有关。在视觉结构/感知方面，存在于 DLB 症状中的幻觉和非幻觉患者之间的差异，对于具有风险认知特征的个体出现 VH 可能是至关重要的。
