Dissociating time and space in navigation in a group of chronic stroke patients

An important, yet complex cognitive ability for adequate daily life functioning is navigation: the ability to find one’s way from one location to another. Navigation is a multicomponent behavior that incorporates both spatially and spatiotemporally based processes. A double dissociation has been recently described in two single cases showing that these elements of navigation ability can be differentiated at a functional level by their spatial or spatiotemporal nature. To verify this finding, navigation deficits in a group of mild stroke patients were assessed, as way finding problems have been found to be common after stroke. 80 mild stroke patients and 60 matched healthy controls watched a route through a realistic virtual environment, after which their knowledge of this route was assessed. Spatial navigation abilities were assessed by way of a scene recognition and a route continuation task. On the other hand, performance on a scene ordering and a route progression task was taken as an indication of the spatiotemporal aspects of navigation. Results indeed support the finding that spatial and spatiotemporal aspects in navigation ability can be selectively impaired after brain damage. This clearly suggests that space and time are at least partially separate features in navigation ability.