Allocentric coordinate spatial representations are impaired in aMCI and Alzheimer's Disease Patients.

Allocentric coordinate spatial representations are impaired in aMCI and Alzheimer's Disease Patients. Behav Brain Res. 2020 Jun 30;:112793 Authors: Ruggiero G, Ruotolo F, Iavarone A, Iachini T Abstract Research has reported deficits in egocentric (subject-to-object) and mainly allocentric (object-to-object) spatial representations in the early stages of the Alzheimer's disease (eAD). To identify early cognitive signs of neurodegenerative conversion, several studies have shown alterations in both reference frames, especially the allocentric ones in amnestic-Mild Cognitive Impairment (aMCI) and eAD patients. However, egocentric and allocentric spatial frames of reference are intrinsically connected with coordinate (metric/variant) and categorical (non-metric/invariant) spatial relations. This raises the question of whether allocentric deficit found to detect the conversion from aMCI to dementia is differently affected when combined with categorical or coordinate spatial relations. Here, we compared eAD and aMCI patients to Normal Controls (NC) on the Ego-Allo/Cat-Coor spatial memory task. Participants memorized triad of objects and then were asked to provide right/left (i.e. categorical) and distance based (i.e. coordinate) judgments according to an egocentric or allocentric reference frame. Results showed a selective deficit of coordinate, but not categorical, allocentric judgments in both aMCI and eAD patients as compared to NC group...
Source: Behavioural Brain Research - Category: Neurology Authors: Tags: Behav Brain Res Source Type: research