How lateralised is visuospatial neglect?

Seventeen patients with left visuospatial neglect caused by cerebral infarction undertook the six subtests of the Behavioural Inattention Test (BIT) as soon as possible following their neurological event. The group mean results on line, letter and star cancellation tasks revealed a linear decrement in performance from right to left on the displays. However, subsequent analysis of patients' cancellations revealed that this finding was not representative of individual performance. Many patients in fact made both marked left- and right-sided omissions on the three cancellation tasks. This was not merely a transitory phenomenon because it remained present at weekly follow-up intervals. Patients' performance on a laterally extended version of the star cancellation task was also investigated. These findings strongly suggest that patients with visuospatial neglect can initially present with a diverse range of performance deficit. Many patients, in particular those with the lowest BIT scores, showed a consistent pattern in the results on letter and star cancellation, providing evidence that their inattention consistently included a considerable section of right-sided (including the extreme right of displays) as well as left-sided space.