Belief and awareness: reflections on a case of persistent anosognosia

Persisting anosognosia after acute lesions is relatively rare, and no case studies to date have reported functional scanning investigation of this disorder. This is a case report of an 85-year-old right-handed Scottish woman, EN, who showed persistent anosognosia for hemiplegia following a haemorrhagic stroke. Extensive damage in the right hemisphere caused left upper and lower limb flaccid hemiplegia and severe left-sided neglect. Lack of awareness for her deficits was still present 2 years after the stroke, when neurological, neuropsychological, and SPECT examinations were performed. Testing revealed severe left unilateral neglect and poor performance on verbal fluency tasks. EN had age normal memory performance, and her object recognition and praxic abilities were preserved. She showed no global reasoning or language problems apart from her abnormal beliefs. EN believed that she was able to walk and carry out several activities, in a context of other disorders of belief. SPECT scan showed marked hypoperfusion in the right parietotemporal cortex and this extended to the associative cortex in the right frontal regions. The persistence of anosognosia in this patient cannot be explained by memory impairments or global cognitive decline. A possible account might be that alteration in awareness was maintained by contingent right frontal and/or parietal dysfunction causing a suspension or change in the ability to monitor and check the 'real' and especially to assess the veracity of mental contents.