Anosognosia for hemiplegia: patient retrospections.

Various competing hypotheses have been put forth to explain how it is possible for patients to be unaware of their own profound weakness. We investigated whether patients' retrospections after resolution of their anosognosia along with their clinical features are consonant with these hypotheses. Three well-educated and articulate men were interviewed about their stroke and their subsequent awareness of weakness. Psychological denial, general cognitive impairment, a faulty superordinate awareness system, lack of knowledge of stroke symptoms, and minimal curiosity as a personality trait were not satisfactory explanations for their anosognosia. Their self-observations and clinical presentations suggest that: (1) anosognosia for hemiplegia can be exquisitely domain-specific; (2) weakness, rather than being perceived automatically, must be discovered; (3) discovery of weakness is impeded by a feedforward intentional deficit which probably interacts with notions of ''body schema'' in complex ways; and (4) awareness of deficit emerges in a graded fashion.