Visual search in relation to spatial working memory
Summary
The organization of visual search can be measured using the star cancellation test, but it is not yet clear which cognitive components influence performance on such visual search tests. Many theories have proposed a close interaction between visual search and working memory. In the current study, 116 stroke patients and 28 healthy controls performed a computerized star cancellation test and a non-lateralized spatial working memory (SWM) test. Two groups, a group with (SWM+) and without (SWM–) SWM problems, were formed based on the SWM threshold derived from the control group (mean + 2.5 SD). We compared performance between the two stroke groups on the outcome measures regarding disorganized search: the number of delayed perseverations, intersection rate (the number of intersections, controlled for total number of markings), and consistency of search direction (best r). Comparisons were made for both a visible and invisible condition (i.e. marks of the patient are visible or invisible, respectively) of the star cancellation test. Furthermore, we calculated correlations between the severity of the SWM deficit and the organization of visual search organization. The SWM+ group made more delayed perseverations, made more intersections, and searched less consistent in both conditions compared to the SWM– group, indicating a relationship between SWM capacity and organization of visual search. Furthermore, a small positive correlation was found between the SWM threshold and intersection rate in both the visible and invisible condition of the star cancellation test, a small negative correlation for the SWM threshold and consistency of search direction in both conditions, and a small positive correlation for the SWM threshold and perseverations, but only in the invisible condition. This indicates a relation between SWM severity and organization of visual search. Together, these findings suggest that there is a small relation between SWM and visual search.