[Neglect: the phenomena of unilateral neglect following brain damage]

The term "neglect" designates various kinds of failure to orient or respond to or to report stimuli appearing at the side contralateral to a cerebral lesion. This failure cannot be explained by primary sensory or motor disorders. Essentially the following symptoms of neglect have been reported: inattention to visual (or) acoustical stimuli in one hemifield under unilateral and simultaneous bilateral presentation reduction in orienting responses (eye and head movements) to the neglected hemispace and deviation of head and gaze axes towards the intact hemispace omission or incomplete reproduction of one side of a figure of a text when copying or drawing from memory omission of one half of a well-known scene or picture when reporting from memory deviation of the egocentre as tested by visual, acoustic and somatesthetic stimuli towards the intact hemispace reduction of motor activities, especially for the extremities of one half of the body, which cannot be attributed to a sensory motor deficit inattention to somatesthetic stimuli presented on one side of the body displacement of somatesthetic stimuli, presented on the affected body side, to the intact body side lack of "awareness" of the existence of one half of the body, resulting in, e.g., ignoring this body half when washing or dressing "reference" of the neglected body half to another person unawareness or denial of severe sensorimotor deficits (e.g. hemiparesis) in the affected body half. The syndrome of neglect should be carefully differentiated from inattention phenomena resulting from primary sensory (e.g. hemianopia, restriction of field of search) and motor deficits (hemiparesis, hemiakinesis). In some cases this differentiation is rather difficult, because both types of inattention may be combined. Thus, detailed testing of sensory and motor disorders is needed in order to avoid any precipitate diagnosis of "neglect". The neuropathology of the neglect syndrome is not yet known precisely. Damage to the parietal lobe (presumably of the nondominant hemisphere) is the most common cause for neglect. Lesions at the bank of the sulcus intraparietalis seem especially crucial. Lesions in the dorsolateral frontal lobe causing neglect are mainly situated in Brodmann's premotor areas 8, 9 and 46. Furthermore, lesions of the anterior cingular cortex (area 24), of the thalamus (intralaminar nuclei, nucleus ventralis lateralis, pulvinar) and of the basal ganglia seem to induce neglect.