Tu Sicong, Wong Stephanie, Hodges John R, Irish Muireann, Piguet Olivier, Hornberger Michael
Neuroscience Research Australia, Randwick, Sydney, Australia; Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia; School of Medical Sciences, University of New South Wales, Sydney, Australia.
Neuroscience Research Australia, Randwick, Sydney, Australia; Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia; School of Psychology, University of New South Wales, Sydney, Australia.
Cortex. 2015 Jun;67:83-94. doi: 10.1016/j.cortex.2015.03.016. Epub 2015 Apr 2.
Spatial disorientation is a prominent feature of early Alzheimer's disease (AD) attributed to degeneration of medial temporal and parietal brain regions, including the retrosplenial cortex (RSC). By contrast, frontotemporal dementia (FTD) syndromes show generally intact spatial orientation at presentation. However, currently no clinical tasks are routinely administered to objectively assess spatial orientation in these neurodegenerative conditions. In this study we investigated spatial orientation in 58 dementia patients and 23 healthy controls using a novel virtual supermarket task as well as voxel-based morphometry (VBM). We compared performance on this task with visual and verbal memory function, which has traditionally been used to discriminate between AD and FTD. Participants viewed a series of videos from a first person perspective travelling through a virtual supermarket and were required to maintain orientation to a starting location. Analyses revealed significantly impaired spatial orientation in AD, compared to FTD patient groups. Spatial orientation performance was found to discriminate AD and FTD patient groups to a very high degree at presentation. More importantly, integrity of the RSC was identified as a key neural correlate of orientation performance. These findings confirm the notion that i) it is feasible to assess spatial orientation objectively via our novel Supermarket task; ii) impaired orientation is a prominent feature that can be applied clinically to discriminate between AD and FTD and iii) the RSC emerges as a critical biomarker to assess spatial orientation deficits in these neurodegenerative conditions.
空间定向障碍是早期阿尔茨海默病（AD）的一个显著特征，这归因于内侧颞叶和顶叶脑区的退化，包括压后皮质（RSC）。相比之下，额颞叶痴呆（FTD）综合征在发病时通常表现出空间定向功能完好。然而，目前尚无常规使用的临床任务来客观评估这些神经退行性疾病中的空间定向。在本研究中，我们使用一种新型的虚拟超市任务以及基于体素的形态学测量（VBM），对58名痴呆患者和23名健康对照者的空间定向进行了研究。我们将该任务的表现与传统上用于区分AD和FTD的视觉和言语记忆功能进行了比较。参与者从第一人称视角观看一系列在虚拟超市中穿行的视频，并被要求保持对起始位置的定向。分析显示，与FTD患者组相比，AD患者的空间定向明显受损。研究发现，空间定向表现能够在很大程度上区分AD和FTD患者组。更重要的是，RSC的完整性被确定为定向表现的关键神经关联因素。这些发现证实了以下观点：i）通过我们的新型超市任务客观评估空间定向是可行的；ii）定向障碍是一个突出特征，可在临床上用于区分AD和FTD；iii）RSC成为评估这些神经退行性疾病中空间定向缺陷的关键生物标志物。
