[Sense of personal identity and focal brain lesions]

The sense of personal identity is an element of the Jasperian definition of self-conscience. Each of us is convinced of being a unique and stable individual, different from other individuals. These properties - stability ad coherence - belong to an image of ourselves that was proposed to us by the Other's look during the mirror phase. Brain focal lesions may threaten this certitude in two ways: 1) brain lesions result in deficiency, disability or handicap, which are experienced as a narcissistic injury. The patient questions himself about the image he offers to the Other's look, and, as a result, his sense of personal identity is unsettled; 2) a variety of focal brain lesions or dysfunctions may alter the activity of areas which are necessary for maintaining a stable image of the patients' body or self. This may lead patients to experience depersonalisation, autoscopy, somatoparaphrenic "delusions" or disturbed agency. The sense of personal identity may be disturbed during brief paroxystic or psychologically traumatic phenomena. However, this is not observed in chronic sequelae of brain lesions (e.g. right hemisphere syndrome or amnesic syndrome), even though the patients may present a broken up image of themselves.