Anosognosia
From Psy3241
Anosognosia is a neuropsychological condition where a person denies that they are suffering from a disability caused by brain injury, such as blindness or paralysis. Anosognosia is thought to be related to unilateral neglect, a condition often found after damage to the non-dominant hemisphere of the cerebral cortex in which sufferers seem unable to attend to, or sometimes comprehend, anything on a certain side of their body. The word anosognosia comes from the Greek words "nosos", meaning disease, and "gnosis", meaning knowledge. The term was first used by the neurologist Joseph Babinski in 1914.
Anosognosia for Hemiplegia
Anosognosia is a fairly common condition, arising from some form of brain injury, such as a stroke. Anosognosia occurs, at least temporarily, in over 50% of stroke victims who suffer from hemiplegia (paralysis on the side of the body opposite the stroke). Patients with anosognosia for hemiplegia insist that they can do things like lift both legs, touch their doctor's nose with a finger on their paralyzed side, and walk normally. These patients are much less likely to regain independence after their stroke than patients without anosognosia, primarily because they overestimate their own abilities in unsafe situations. Amazingly, many anosognosiacs also seem unable to recognize their own limitations in other people. In a recent experiment, Vilayanur Ramachandran found that two thirds of tested hemiplegic anosognosiacs were not able to recognize paralysis in another person. He suggests that this is because we have a schema for ourselves, as well as the bodies of others, and that they are represented in close proximity in our brains.
Treatment
Two methods of treatment are currently used to help bring a sense of awareness of failure to anosognosiacs. The first method involves pouring ice cold water into the ear of the patient on the side of the paralysis. Since nerves in the ear contribute information about the body's balance to the brain, by shocking these nerves the part of the body responsible for updating the body schema with new information may be startled. This treatment method seems to work quite well, and patients undergoing this treatment often fully realize their paralysis for several hours. The second method of treatment uses virtual reality programming to give patients repeated feedback about their failures in a safe setting.
There are, however, currently no long-term treatments for patients with anosognosia. Most cases of anosognosia seem to disappear over time, while other cases can last indefinitely. Normally, long-term cases are treated with cognitive therapy to train the patient to adjust for their inoperable limbs (though it is believed that these patients still are not "aware" of their disability).
