Anosognosia (/æˌnɒsɒɡˈnoʊziə/, /æˌnɒsɒɡˈnoʊʒə/; from Ancient Greek ἀ- a-, "without", νόσος nosos, "disease" and γνῶσις gnōsis, "knowledge") is viewed as a deficit of self-awareness, a condition in which a person who suffers certain disability seems unaware of the existence of his or her disability. It was first named by the neurologist Joseph Babinski in 1914. Anosognosia results from physiological damage on brain structures, typically to the parietal lobe or a diffuse lesion on the fronto-temporal-parietal area in the right hemisphere. Whilst this distinguishes the condition from denial, which is a psychological defense mechanism, attempts have been made at a unified explanation. Both anosognosia and denial are almost always connected with damage in the right hemisphere. Split-brain research suggests that this asymmetry points to a neurological answer. Anosognosia is sometimes accompanied by asomatognosia, a form of neglect in which patients deny ownership of their limbs.
