Study on the occurrence and neural bases of hemispatial neglect with different reference frames.

OBJECTIVES To study the distributions and the neural correlates of left hemispatial neglect with different reference frames. DESIGN Data were collected from patients with right brain injury who participated in a case series. SETTING Hospital departments of rehabilitation and neurology. PARTICIPANTS Right brain-damaged patients (N=110). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES The frequency of left hemispatial neglect with different reference frames was investigated, and the respective brain lesions were displayed and analyzed. RESULTS Not all subjects finished predesigned neglect tests because of their condition: 8 of the 55 neglect patients were unable to complete the test for classification. Thirty (63.83%) of 47 subjects with neglect displayed both allocentric and egocentric neglect, while 17 subjects showed pure egocentric neglect. The lesions in the inferior frontal gyrus, precentral gyrus, postcentral gyrus, superior temporal gyrus (STG), middle temporal gyrus (MTG), insula, and surrounding white matters were more frequent in the neglect group than in the control group. Compared with the egocentric neglect group, the lesions in the right STG, MTG, lenticular nucleus, and the surrounding white matter were damaged more frequently in the group displaying both allocentric and egocentric neglect. CONCLUSIONS More than half of the subjects with left neglect after right brain injury have both egocentric and allocentric neglect. The right inferior frontal gyrus, precentral gyrus, postcentral gyrus, STG, MTG, insula, and the surrounding white matter are associated with left hemispatial neglect. Left allocentric neglect is associated with the right STG, MTG, and lenticular nucleus.