Real-space navigation testing differentiates between amyloid-positive and -negative aMCI.
Neurology. 2020 Jan 2. pii: 10.1212/WNL.0000000000008758. doi: 10.1212/WNL.0000000000008758. [Epub ahead of print]
|Authors/Editors:||Schöberl F, Pradhan C, Irving S, Buerger K, Xiong G, Kugler G, Kohlbecher S, Engmann J, Werner P, Brendel M, Schneider E, Perneczky R, Jahn K, la Fougère C, Bartenstein P, Brandt T, Dieterich M, Zwergal A.|
To distinguish between patients with amyloid-positive (A+) and -negative (A−) amnestic mild cognitive impairment (aMCI) by simultaneously investigating navigation performance, visual exploration behavior, and brain activations during a real-space navigation paradigm.
Twenty-one patients with aMCI were grouped into A+ (n = 11) and A− cases by amyloid-PET imaging and amyloid CSF levels and compared to 15 healthy controls. Neuropsychological deficits were quantified by use of the Consortium to Establish a Registry for Alzheimer’s Disease–plus cognitive battery. All participants performed a navigation task in which they had to find items in a realistic spatial environment and had to apply egocentric and allocentric route planning strategies. 18F-fluorodeoxyglucose was injected at the start to detect navigationinduced brain activations. Subjects wore a gaze-controlled, head-fixed camera that recorded
their visual exploration behavior.
A+ patients performed worse during egocentric and allocentric navigation compared to A− patients and controls (p < 0.001). Both aMCI subgroups used fewer shortcuts, moved more slowly, and stayed longer at crossings. Word-list learning, figural learning, and Trail-Making tests did not differ in the A+ and A− subgroups. A+ patients showed a reduced activation of the right hippocampus, retrosplenial, and parietal cortex during navigation compared to A− patients (p < 0.005).
A+ patients with aMCI perform worse than A− patients with aMCI in egocentric and allocentric route planning because of a more widespread impairment of their cerebral navigation network. Navigation testing in real space is a promising approach to identify patients with aMCI with underlying Alzheimer pathology.