Path integration changes as a cognitive biomarker for vascular cognitive impairment? A pilot study

Abstract

AbstractBackgroundPath integration spatial navigation processes are emerging as promising cognitive biomarkers for prodromal and clinical Alzheimer’s disease (AD). However, such path integration changes have been little explored in Vascular Cognitive Impairment (VCI),despite neurovascular change being a major contributing factor to dementia and potentially AD. In particular, the sensitivity and specificity of path integration impairments in VCI compared to AD is unclear. In the current pilot study, we explore path integration performance in AD and VCI patient groups and hypothesise that i) medial parietal mediated egocentric processes will be more affected in VCI and ii) medial temporal mediated allocentric processes will be more affected in AD.MethodThe cross‐sectional study included early stage VCI patients (n=9), AD patients (n=10) and healthy age‐matched controls (n=20). All participants underwent extensive neuropsychological testing, as well as spatial navigation testing. The spatial navigation tests included the virtual reality ‘Supermarket’ task assessing egocentric (body‐based) and allocentric (map‐based) navigation as well as the ‘Clock Orientation’ test assessing egocentric and path integration processes.ResultFindings showed that egocentric path integration processes are only impaired in VCI, potentially distinguishing it from AD. Whereas, allocentric path integration was similarly impaired for VCI and AD. Egocentric scores of Supermarket and Clock Orientation predictors explained 77% (Nagelkerke R 2 ) of variance in VCI and AD patients and correctly classified 84% of patients (7 out of 9 VCI; 9 out of 10 AD) into their respective cohorts. ROC curves were computed and similarly, Area Under the Curve (AUC) values indicated that egocentric orientation in the Supermarket (AUC = .8, SE = .12; 95% CI [.56, 1]) and Clock test (AUC= .91, SE = .06, 95% CI [.8, 1]) had strong diagnostic accuracy in distinguishing VCI from AD patients.ConclusionThese preliminary findings suggest egocentric path integration deficits emerge as more specific to VCI, potentially allowing for more specific diagnostic and treatment outcome measures for vascular impairment in dementia. By contrast, there was limited specificity of allocentric path integration deficits between VCI and AD.