INSERM, University of Montpellier, Neuropsychiatry: Epidemiological and Clinical Research, Montpellier, France.
Centre for Dementia Prevention, University of Edinburgh, UK.
J Alzheimers Dis. 2018;65(3):885-896. doi: 10.3233/JAD-180432.
Impairments in spatial processing due to hippocampal degeneration have been observed in the years immediately preceding the diagnosis of Alzheimer's disease (AD) dementia. The demonstration of changes in spatial processing in preceding decades would provide a cognitive marker for pre-clinical AD and an outcome measure for early intervention trials. The present study examined allocentric and egocentric spatial processing in relation to future dementia risk in a middle-aged cohort. The CAIDE Dementia Risk Score (DRS) was calculated for 188 persons aged 40 to 59, of whom 94 had a parent with dementia. Participants underwent the Four Mountains Test (4MT) of allocentric spatial processing, the Virtual Reality Supermarket Trolley Task (VRSTT) of egocentric spatial processing, and 3T MRI scans. A significant negative association was found between the DRS and 4MT (Spearman correlation - 0.26, p = 0.0006), but not with the VRSTT. The 4MT was also found to be a better predictor of risk than tests of episodic memory, verbal fluency, or executive functioning. The results suggest that allocentric rather than egocentric processing may be a potential indicator of risk for late-onset AD, consistent with the hypothesis that the earliest cognitive changes in AD are driven by tau-related degeneration in the medial temporal lobe rather than amyloid-only deposition in the medial parietal lobe.
由于海马体退化导致的空间处理障碍在阿尔茨海默病（AD）痴呆症诊断前的几年中就已经被观察到。在数十年前就发现空间处理的变化，将为 AD 的临床前阶段提供认知标志物，并为早期干预试验提供结果衡量标准。本研究在中年队列中检查了与未来痴呆风险相关的定位和自我中心空间处理。为 188 名年龄在 40 至 59 岁的人计算了 CAIDE 痴呆风险评分（DRS），其中 94 人的父母患有痴呆症。参与者接受了定位空间处理的 Four Mountains Test（4MT）、自我中心空间处理的 Virtual Reality Supermarket Trolley Task（VRSTT）以及 3T MRI 扫描。DRS 与 4MT 呈显著负相关（Spearman 相关系数 -0.26，p=0.0006），但与 VRSTT 无关。4MT 比情节记忆、言语流畅性或执行功能测试更能预测风险。研究结果表明，定位处理而非自我中心处理可能是 AD 迟发性发病风险的潜在指标，这与 AD 最早的认知变化是由内侧颞叶的 tau 相关退化而不是内侧顶叶的淀粉样蛋白沉积驱动的假设一致。
