Looking at both sides now: An explorative study investigating non-lateralized dysfunctions in hemispatial neglect and in various spatial frames of reference.

Abstract

Hemispatial neglect is an enabling disorder that is most common after right-sided brain lesions and is perceived as a heterogeneous syndrome. For example, patients can show neglect in different sensory modalities (visual, auditory, e.g.) and at different spatial distances (near and far). According to recent studies, neglect is related to non-lateralized impairments such as deficits in selective attention, sustained attention and spatial working memory. Based on these non-lateralized dysfunctions found in neglect patients, the current study explored whether there would be a difference between neglect patients (n = 59) and stroke patients without neglect (n = 127) on a neuropsychological test battery, containing tests that measured the non-lateralized functions short term memory, working memory, executive functioning (planning, mental flexibility) and (divided) attention. In addition, research shows that the degree of certain non-lateralized impairments correlates with the severity of the hemispatial neglect. In the present study, this was also investigated for the (non-lateralized) domains memory and executive functioning. The final part of the study focused on the association between non-lateralized dysfunctions and hemispatial neglect in different regions of space. Because of the dissociation between neglect in near- and in far space, the present study investigated whether patients with neglect in near space (n= 17) and neglect in far space (n = 14) would perform differently on the test battery. The test results reveal that neglect patients do not perform better or worse on the neuropsychological tests included in the test battery compared to the stroke patients without neglect. Moreover, there was no relation between neglect severity and cognitive performance on the domains memory and executive functioning. Finally, the results show there are no differences in cognitive profile between the patients with neglect in near space and the patients with neglect in far space. It is suggested that the test results of the present study can be accounted for by the anatomical organization of non-lateralized functions, and its association with the brain sites related to the neglect syndrome.