ABSTRACT

Psychosis is frequent in Alzheimer’s disease (AD) and it is associated with a worse disease course. AD psychosis may represent a distinct AD phenotype, though its specific neurobiological underpinnings have yet to be identified. This study investigated neural underpinnings of AD psychosis using surface-based-morphometry.Data from 32 AD patients, 17 with psychosis (AD-P) and 15 without were analyzed. Average cortical complexity (fractal dimension, FD) was estimated for each theoretically motivated ROI and patient. First, we compared regional FD in AD-P and AD patients. Then we calculated the correlation coefficients between FD and the severity of misidentification and paranoid psychotic symptoms. AD-P showed decreased FD in ventral-visual-stream compared to AD, suggesting that perceptual processes might be pivotal in psychosis. A negative correlation was found between misidentification severity and FD in the entorhinal cortex suggesting that misidentification may be specifically associated with alterations in regions involved in high-level perceptual and contextualization processes.

摘要

精神病在阿尔茨海默病 (AD) 中很常见，并且与更严重的病程有关。AD 精神病可能代表一种独特的 AD 表型，尽管其特定的神经生物学基础尚未确定。本研究使用基于表面的形态测量法研究了 AD 精神病的神经基础。分析了 32 名 AD 患者的数据，其中 17 名患有精神病 (AD-P)，15 名没有精神病。估计每个理论上有动机的 ROI 和患者的平均皮质复杂度（分形维数，FD）。首先，我们比较了 AD-P 和 AD 患者的区域 FD。然后我们计算了FD与误认严重程度和偏执型精神病症状之间的相关系数。与 AD 相比，AD-P 显示腹侧视觉流中的 FD 减少，这表明知觉过程可能是精神病的关键。