Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, USA.
Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
J Alzheimers Dis. 2022;89(1):133-149. doi: 10.3233/JAD-215107.
Hallucinations in Alzheimer's disease (AD) have been linked to more severe cognitive and functional decline. However, research on visual hallucinations (VH), the most common type of hallucinations in AD, is limited.
To investigate the cognitive and cerebral macrostructural and metabolic features associated with VH in AD.
Twenty-four AD patients with VH, 24 with no VH (NVH), and 24 cognitively normal (CN) matched controls were selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Differences in regional gray matter (GM) volumes and cognitive performance were investigated with whole brain voxel-based morphometry analyses of MRI structural brain scans, and analyses of neuropsychological tests. Glucose metabolic changes were explored in a sub-sample of patients who had FDG-PET scans available.
More severe visuoconstructive and attentional deficits were found in AD VH compared with NVH. GM atrophy and hypometabolism were detected in occipital and temporal areas in VH patients in comparison with CN. On the other hand, NVH patients had atrophy and hypometabolism mainly in temporal areas. No differences in GM volume and glucose metabolism were found in the direct comparison between AD VH and NVH.
In addition to the pattern of brain abnormalities typical of AD, occipital alterations were observed in patients with VH compared with CN. More severe visuoconstructive and attentional deficits were found in AD VH when directly compared with NVH, and might contribute to the emergence of VH in AD.
阿尔茨海默病（AD）中的幻觉与更严重的认知和功能下降有关。然而，对 AD 中最常见的幻觉——视幻觉（VH）的研究有限。
研究与 AD 中的 VH 相关的认知、大脑宏观结构和代谢特征。
从阿尔茨海默病神经影像学倡议（ADNI）数据库中选择了 24 名有 VH 的 AD 患者、24 名无 VH（NVH）的患者和 24 名认知正常（CN）的匹配对照者。通过对 MRI 结构脑扫描的全脑体素形态计量学分析以及神经心理学测试，研究了区域性灰质（GM）体积和认知表现的差异。在有 FDG-PET 扫描的患者亚组中探讨了葡萄糖代谢变化。
与 NVH 相比，AD VH 患者表现出更严重的视空间构建和注意力缺陷。与 CN 相比，VH 患者的枕叶和颞叶区域出现 GM 萎缩和代谢减退。另一方面，NVH 患者主要在颞叶区域出现萎缩和代谢减退。在 AD VH 和 NVH 之间的直接比较中，GM 体积和葡萄糖代谢没有差异。
除了 AD 典型的脑异常模式外，还观察到 VH 患者的枕叶改变。与 NVH 相比，AD VH 患者的视空间构建和注意力缺陷更严重，这可能导致 AD 中出现 VH。
