Herchel Smith Building for Brain and Mind Sciences, Department of Clinical Neurosciences, Neurology Unit, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
J Alzheimers Dis. 2010;21(4):1347-65. doi: 10.3233/jad-2010-100654.
The neural network activated during Topographical Memory (TM) tasks in controls overlaps with the earliest affected regions in Alzheimer's disease (AD) but not with those of Semantic Dementia (SD). This suggests that clinical TM tests could be more bespoke to neural dysfunction in early AD and therefore more sensitive and specific. We hypothesized that TM impairment would be characteristic of AD but not of SD making it useful both for early diagnosis and differential diagnosis. TM was assessed in 69 patients (22 mild AD, 15 SD, 32 with mild cognitive impairment (MCI)) and 35 controls, using three tasks: the four mountains test and two novel tests in a virtual town (the Virtual Route Learning Test (VRLT) and the Heading Orientation Test). AD patients were impaired on all TM tasks. The VRLT was the most discriminatory; had the highest correlation with caregiver reports of navigation problems; and correlated strongly with memory, attention/executive function, and to a lesser degree, visuospatial ability. In contrast, SD patients performed well on the TM battery only becoming abnormal with very advanced dementia and performance correlated exclusively with attention/executive function. The VRLT achieved 95% sensitivity and 94% specificity in discriminating AD patients from controls; at the same cutoff, 70% of MCI patients were impaired. When combined with either naming performance or global dementia severity, there was complete separation of AD from SD. The VRLT is ecologically valid, highly sensitive to early AD, and useful in discriminating AD from the non-Alzheimer dementia, SD.
在控制组中，进行拓扑记忆（TM）任务时激活的神经网络与阿尔茨海默病（AD）最早受影响的区域重叠，但与语义性痴呆（SD）的区域不重叠。这表明临床 TM 测试可能更适合 AD 的神经功能障碍，因此更敏感和特异。我们假设 TM 损伤将是 AD 的特征，但不是 SD 的特征，这使其在早期诊断和鉴别诊断中都很有用。使用三项任务（四山测试和两个虚拟城镇中的新测试，即虚拟路线学习测试（VRLT）和朝向定向测试）评估了 69 名患者（22 名轻度 AD、15 名 SD、32 名轻度认知障碍（MCI））和 35 名对照者的 TM。AD 患者在所有 TM 任务中都受损。VRLT 是最具鉴别力的；与照顾者报告的导航问题相关性最高；与记忆、注意力/执行功能高度相关，与视觉空间能力的相关性稍低。相比之下，SD 患者在 TM 电池测试中表现良好，仅在非常严重的痴呆时才变得异常，且与注意力/执行功能相关。VRLT 在区分 AD 患者和对照组方面达到了 95%的敏感性和 94%的特异性；在相同的截止值下，70%的 MCI 患者受损。当与命名表现或整体痴呆严重程度相结合时，AD 与 SD 完全分离。VRLT 具有生态有效性，对早期 AD 高度敏感，并且有助于区分 AD 与非阿尔茨海默病痴呆症 SD。
