Differentiating spatial neglect from primary sensory-motor deficits

Unilateral spatial neglect is one of the most complex cognitive disorders, caused by unilateral brain damage, mainly the right hemisphere. It incorporates different variants (left-, right-sided), types (perceptual, motor, imaginal) and forms of symptoms (defective, productive), revealing themselves in different ranges (personal, peri-personal, extra-personal) and spatial references (egocentric, allocentric). With such clinical complexity, the major subtypes of neglect (visual, tactile, motor) also need to be differentiated from primary sensory-motor deficits. This differentiation sometimes turns out to be difficult because the compared disorders may occur independently or coexist, exacerbating, imitating, or masking each other’s symptoms. However, it is necessary due to differences in prognosis, patterns of spontaneous improvement and methods of treatment of variously conditioned disorders. Due to the complexity of the neglect syndrome, there is no single tool allowing for the differential diagnosis of all its symptoms, nor uniform rules regarding the management in this regard. The diagnosis should be based on the observation of spontaneous behavior, the use of appropriate diagnostic tests and, if necessary, neurophysiological interventions and instrumental measurements. The features of neglect include: 1) functional difficulties contralateral to brain damage, 2) side asymmetry in the performance of diagnostic tests, 3) limited self-awareness of deficits, 4) multi-modality of symptoms, 5) abnormalities in response to ipsilesional stimuli, 6) damage to the parietal structures, mainly the right hemisphere, 7) stroke etiology, 8) modulating influence of attention-spatial strategies on the nature of dysfunctions, and 9) difficulty in self-compensation of disorders.