Les Manifestations De Negligence et D'inattention Pour L'hemispace

Abstract

All the patients with unilateral brain damage admitted to our Clinic during a period of 15 months were given a battery of tests with the aim of detecting the possible existence of unilateral spatial agnosia. In the same patients, investigations were carried out to study somatosensory and visual field defects, general mental impairment, unilateral alterations of the bodyschema, disturbances of eye movements, and modifications of the personality. Relationships between all these symptoms and A.S.U. were studied. All our tests indicated that A.S.U. is significantly more frequent among right brain-damaged patients. Similar, but definitely less severe, disturbances were found in a few patients with left brain damage, within the setting of severe somatosensory and visual field defects, and of intellectual impairment. Unilateral spatial agnosia was considered in these patients as a symptom reflecting “inattention” for what is placed in a section of the space which is out of their actual visual field. This interpretation was found, on the contrary, insufficient to explain the severe manifestations of neglect evidenced by many right brain-damaged patients. The symptoms more strickly correlated with A.S.U. were: a) somatosensory and visual field defects, b) disturbances of the eye movements, c) unilateral alterations of the body-schema. None of them, however, were found indispensable in the production of the A.S.U. Since disturbances of eye movements and unilateral alterations of the bodyschema seemed to be caused by the same mechanism responsible for the neglect of the left half of the space, the significance of A.S.U. was investigated by chiefly keeping in mind the probable characteristics of differential hemispheric organisation of the somatic and visual sensory data. According tho the hypothesis of Hecaen and Angelergues it seems justifiable in effects to suppose that sensory data have a different functional organisation in the two halves of the brain. It is suggested that in the dominant hemisphere sensory data receive a conceptual elaboration by means of language. On the contrary, in the minor hemisphere, where language mechanisms are not represented, their synthesis maintains characteristics of immediateness and of rich affective value. Disorganisation of this last type of synthesis of the sensory data is supposed to cause the non-existence, for the patient, corresponding half of the body and of space (unilateral spatial neglect). Some anatomical data (relatively modest) are in favor of a severe disorganisation localized in the cerebral regions where this synthesis occurs.