Cerebral blood flow SPECT imaging in right hemisphere-damaged patients with hemispatial neglect. A pilot study.

Hemispatial neglect is characterised as a failure by a brain-damaged patient to attend to contralesional space. It is hypothesised to be a result of damage to a network involving the frontal, parietal and cingulated cortices, basal ganglia and thalamus.The aim of this preliminary study was to verify this model of neglect in 22 right hemisphere-damaged acute stroke patients, using single photon emission-computed tomography (SPECT). The presence of a single right-sided vascular brain lesion was confirmed on CT and/or MRI. Hemispatial neglect, assessed with a battery of drawings, line bisection and line and shape cancellation tests, was observed in 12 cases.Patients with neglect (compared with those without neglect) had more extensive hypoperfusion in the frontal and parietal cortex, as well as striatum and thalamus. Left-sided hypoperfusion in the parietal cortex and the thalamus was also significantly associated with neglect on SPECT imaging. Performance in three out of five psychological tasks commonly used to detect the presence of hemispatial neglect, such as drawing tests and line bisection test, was exclusively linked with damage to the parietal cortex of the right hemisphere, while the line cancellation test might be attributable to the lesion of the right striatum.These findings support the model attributing hemispatial neglect to a unilateral defect in a cortico-striatothalamo-cortical loop. CBF SPECT imaging may provide a reliable description of the brain pathology associated with hemispatial neglect.