Double dissociations between neglect tests: possible relation to lesion site.

In 20 patients who had suffered a first right hemisphere stroke, we examined the prevalence of double dissociations between the results of a star cancellation and a line bisection test. Both are common methods to assess spatial hemineglect. Within the group of neglect patients, we found no significant correlation between the two tasks. Furthermore, 5 patients with impaired performance on one of the tests were within the normal range on the other one. In agreement with experimental studies, we argue that spatial hemineglect is not a unitary syndrome. Furthermore, the findings in one of our patients are compatible with the view that an isolated deficit on cancellation tasks might follow from a lesion in the right anterior cingulate gyrus.