Increasing cognitive demand in assessments of visuo-spatial neglect: Testing the concepts of static and dynamic tests.

Introduction: Numerous tests of visuo-spatial neglect (VSN) have been developed. In this study, we propose a clustering of VSN tests by making a distinction between static tests with low levels of cognitive demand (i.e. tests without movement or time-restrictions, such as paper-and-pencil tests) and dynamic tests with high levels of cognitive demand (i.e. tests incorporating movement and time-restrictions, such as virtual reality tests). The concepts of static and dynamic tests have not been systematically investigated so far. Here, we investigated (1) whether we would find dissociations between patients showing VSN on test within the static cluster but not on tests within the dynamic cluster, and vice versa; (2) whether differences in demographic or clinical characteristics could be identified between these groups of patients; and (3) whether the underlying factor structure would correspond to our proposed distinction between static and dynamic clusters of tests.

Method: Sixty-one patients with VSN completed three static tests (shape cancellation, line bisection, letter cancellation) and three dynamic tests (Catherine Bergego Scale, Mobility Assessment Course, simulated driving test).

Results: Thirteen percent of patients showed VSN on tests within the static cluster, 33% on tests within the dynamic cluster, and 54% on tests within both clusters. Patients with VSN on the dynamic tests (alone or in addition to static tests) had poorer motor function, poorer walking abilities and were more dependent in daily life than patients showing VSN on the static cluster alone. The underlying factor structure corresponded to our proposed conceptual distinction between static and dynamic clusters of tests.

Conclusions: Static and dynamic tests compose different clusters and double dissociations are shown between clusters. Future research involving data-driven approaches might result in a better understanding on how different tests of VSN relate to each other, and, more importantly, a better understanding of VSN and its phenotypes.