Do visual field deficits exacerbate visuo-spatial neglect?

A significant association between visual field deficits (VFD) and visuo-spatial neglect is well established, although cases of double-dissociation between the two conditions are not uncommon. It has been argued that VFD typically exacerbates the behavioural manifestations of neglect. We examined a series of 51 patients with unilateral right-hemisphere stroke for the presence of visual field deficit and visuo-spatial neglect. Patients were assigned to the neglect group (N+) or the non-neglect group (N-) on the basis of their aggregate scores on the recently standardised Behavioural Inattention Test (BIT). The association between neglect and VFD was confirmed. Four groups of eight patients (N+, VFD+; N+, VFD-; N-, VFD+; N-, VFD-) were then selected from the initial sample so that they were matched for age, IQ, and days post onset of stroke. Within the neglect groups, the severity of neglect did not differ significantly between those patients with and without VFD; within the non-neglect groups, scores on subtests of the BIT likewise did not differ (with the sole exception of Letter Cancellation) between the VFD+ and the VFD- subgroups. It was concluded that visual field deficits do not exacerbate neglect, and that poor functional recovery in many patients with VFDs is due to the association of sensory loss with the underlying causal factor of neglect.