You never know where you are going until you know where you have been: Disorganized search after stroke

Abstract

Disorders in spatial exploration can be expressed in a disorganized fashion of target cancellation. There is debate regarding whether disorganized search is related to stroke in general, to right brain damage or to unilateral spatial neglect (USN) in particular. In this study, 280 stroke patients and 37 healthy control subjects performed a computerized shape cancellation test. We investigated the number of perseverations and several outcome measures regarding disorganized search: Consistency of search direction (best r), distance between consecutive cancelled targets and intersections with paths between previous cancelled targets. We compared performance between patients with left and right brain damage (L, R) and with and without USN (USN+, USN-), resulting in four subgroups: LUSN-, RUSN-, LUSN+, and RUSN+. Higher numbers of intersections were found for the left brain- and right brain-damaged patients with USN and for the right brain-damaged patients without USN, compared to healthy control subjects. Furthermore, right brain-damaged patients with USN showed a higher number of intersections compared to right brain-damaged patients without USN and compared to left brain-damaged patients with USN. To conclude, disorganized search was most strongly related to the neglect syndrome, and patients with more severe USN were even more impaired.