History of Anosognosia

Even if Babinski (1914) is usually considered as the discoverer of anosognosia, other authors before him contributed to the development of this construct. Von Monakow (1885) and Dejerine and Vialet (1893) gave the first descriptions of patients with cortical blindness who were unaware of their disability, but did not distinguish this unawareness from the rest of the clinical description. Anton (1999) described patients with cortical deafness and cortical blindness, considering these defects of awareness as a symptom independent from the neurological dysfunction. He conceptualized them as a phenomenon in its own right and tried to link this unawareness of a disability with specific neuro-anatomical changes. Finally, Babinski (1914) coined the term "anosognosia" to designate the clinical entity conceptualized by Anton (1899) and extended this concept from the unawareness of cortical deafness and blindness to the unawareness of hemiplegia. The choice of the term "anosognosia" to denote the observed phenomenon was important, because referring to "lack of knowledge of the disease" (anosognosia), he not only emphasized the separation between "lack of knowledge" and "disease, " but also suggested a general use of this term, because disease can refer to many other disabilities besides hemiplegia. Further investigations have shown that: (a) brain-damaged patients may be unaware of different kinds of disabilities; (b) anosognosia can be selective, in that an affected person with multiple impairments may be unaware of only one handicap, while appearing fully aware of any others; and (c) lack of acknowledgment of a disease may not necessarily be due to a defective awareness, but must sometimes be considered as an extreme but understable pattern of adaptation to stress. For this condition, the term "Denial of Illness" seems preferable to that of anosognosia. Anosognosia must perhaps be viewed as a multifaceted phenomenon, resulting from both cognitive and motivational factors.