Somatoparaphrenia, anosognosia, and the neglect syndrome

The symptom-complex of somatoparaphrenia (SCS) is reviewed. The deficit typically occurs in the context of the syndrome of unilateral spatial neglect, is associated with many of its manifestations, and largely shares its hemispheric asymmetries, and neural correlates. SCS’ main manifestation is a reported feeling of estrangeness – disownership of contralesional body parts, that is frequently associated with deficits of tactile sensation and proprioception, extra-personal neglect, and anosognosia for hemiplegia, although dissociations are on record. Particularly, the feeling of disownership may occur independent of the patient’s ability to explore the contralesional side of the body (personal neglect or emisomatoagnosia), suggesting that (dis)ownership of body parts relies on mechanisms independent of those concerned with awareness of those body parts. A case study of a right-brain-damaged patient with left STS is presented, investigating the role of perceptual and intentional components in the shaping of the SCS.