Anosognosia
Encyclopedia
Anosognosia /æˌnɒsɒgˈnəʊsɪə/ is a condition in which a person who suffers disability
seems unaware of the existence of his or her disability. Unlike denial
, which is a defense mechanism, anosognosia is rooted in physiology (for example, damage to the frontal or parietal lobe due to illness and disease). This may include unawareness of quite dramatic impairments, such as blindness
or paralysis
. It was first named by the neurologist
Joseph Babinski
in 1914. Relatively little has been discovered about the cause of the condition since its initial identification. The word comes from the Greek words "nosos" disease and "gnosis" knowledge (an- / a- is a negative prefix).
/hemiparesis
after stroke
), but can appear to occur in conjunction with virtually any neurological impairment. But, it is not related to global mental confusion
, cognitive flexibility
, or other major intellectual disturbance. Anosognosia can be selective in that an affected person with multiple impairments may seem unaware of only one handicap, while appearing to be fully aware of any others. Those diagnosed with dementia of the Alzheimer's type
often display this lack of awareness and insist that nothing is wrong with them.
The condition does not seem to be directly related to sensory loss and is thought to be caused by damage to higher level neurocognitive
processes that are involved in integrating sensory information with processes that support spatial or bodily representations (including the somatosensory system). Anosognosia is thought to be related to unilateral neglect, a condition often found after damage to the non-dominant (usually the right) hemisphere of the cerebral cortex
in which sufferers seem unable to attend to, or sometimes comprehend, anything on a certain side of their body (usually the left).
Anosognosia may occur as part of Wernicke's aphasia
, a language disorder that causes poor comprehension of speech and the production of fluent but incomprehensible sentences. A patient with Wernicke's aphasia cannot correct his own phonetic
errors and shows "anger and disappointment with the person with whom he is speaking because that person fails to understand him." This may be a result of brain damage to the posterior portion of the superior temporal gyrus
, believed to contain representations of word sounds. With those representations destroyed, patients with Wernicke's aphasia are unable to monitor their mistakes. Other patients with Wernicke's aphasia are fully aware of their condition and speech inhibitions, but cannot monitor their condition, which is not the same as anosognosia and therefore cannot explain the occurrence of neologistic jargon.
. They do not have the insight to recognize that they suffer from a mental illness. There is evidence that schizophrenic anosognosia may be the result of frontal lobe damage.
One study of voluntary and involuntary inpatients confirmed that committed patients require coercive treatment because they fail to recognize their need for care. Predictably, the patients committed to the hospital had significantly lower measures of insight than the voluntary patients.
Anosognosia is also closely related to other cognitive dysfunctions that may impair the capacity of an individual to continuously participate in treatment. Other research has suggested that attitudes toward treatment can improve after involuntary treatment and that previously committed patients tend later to seek voluntary treatment.
In regard to anosognosia for neurological patients, no long-term treatments exist. As with unilateral neglect, caloric reflex testing (squirting ice cold water into the left ear) is known to temporarily ameliorate unawareness of impairment. It is not entirely clear how this works, although it is thought that the unconscious shift of attention
or focus caused by the intense stimulation of the vestibular system temporarily influences awareness. Most cases of anosognosia appear to simply 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).
Disability
A disability may be physical, cognitive, mental, sensory, emotional, developmental or some combination of these.Many people would rather be referred to as a person with a disability instead of handicapped...
seems unaware of the existence of his or her disability. Unlike denial
Denial
Denial is a defense mechanism postulated by Sigmund Freud, in which a person is faced with a fact that is too uncomfortable to accept and rejects it instead, insisting that it is not true despite what may be overwhelming evidence.The subject may use:* simple denial: deny the reality of the...
, which is a defense mechanism, anosognosia is rooted in physiology (for example, damage to the frontal or parietal lobe due to illness and disease). This may include unawareness of quite dramatic impairments, such as blindness
Blindness
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
or paralysis
Paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
. It was first named by the neurologist
Neurologist
A neurologist is a physician who specializes in neurology, and is trained to investigate, or diagnose and treat neurological disorders.Neurology is the medical specialty related to the human nervous system. The nervous system encompasses the brain, spinal cord, and peripheral nerves. A specialist...
Joseph Babinski
Joseph Babinski
Joseph Jules François Félix Babinski was a French neurologist of Polish descent. He is best known for his 1896 description of the Babinski sign, a pathological plantar reflex indicative of corticospinal tract damage....
in 1914. Relatively little has been discovered about the cause of the condition since its initial identification. The word comes from the Greek words "nosos" disease and "gnosis" knowledge (an- / a- is a negative prefix).
Causes
Anosognosia is relatively common following brain injury (e.g. 10%–18% in the case of hemiplegiaHemiplegia
Hemiplegia /he.mə.pliː.dʒiə/ is total paralysis of the arm, leg, and trunk on the same side of the body. Hemiplegia is more severe than hemiparesis, wherein one half of the body has less marked weakness....
/hemiparesis
Hemiparesis
Hemiparesis is weakness on one side of the body. It is less severe than hemiplegia - the total paralysis of the arm, leg, and trunk on one side of the body. Thus, the patient can move the impaired side of his body, but with reduced muscular strength....
after stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
), but can appear to occur in conjunction with virtually any neurological impairment. But, it is not related to global mental confusion
Mental confusion
Confusion of a pathological degree usually refers to loss of orientation sometimes accompanied by disordered consciousness and often memory Confusion (from Latin confusĭo, -ōnis, noun of action from confundere "to pour together", also "to confuse") of a pathological degree usually refers to loss...
, cognitive flexibility
Cognitive flexibility
Cognitive flexibility is the term used to describe one of the executive functions; a function which is an important component of human behavior; the ability to switch behavioral response according to the context of the situation...
, or other major intellectual disturbance. Anosognosia can be selective in that an affected person with multiple impairments may seem unaware of only one handicap, while appearing to be fully aware of any others. Those diagnosed with dementia of the Alzheimer's type
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
often display this lack of awareness and insist that nothing is wrong with them.
The condition does not seem to be directly related to sensory loss and is thought to be caused by damage to higher level neurocognitive
Neurocognitive
Neurocognitive is a term used to describe cognitive functions closely linked to the function of particular areas, neural pathways, or cortical networks in the brain substrate layers of neurological matrix at the cellular molecular level...
processes that are involved in integrating sensory information with processes that support spatial or bodily representations (including the somatosensory system). Anosognosia is thought to be related to unilateral neglect, a condition often found after damage to the non-dominant (usually the right) hemisphere of the cerebral cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
in which sufferers seem unable to attend to, or sometimes comprehend, anything on a certain side of their body (usually the left).
Anosognosia may occur as part of Wernicke's aphasia
Receptive aphasia
Receptive aphasia, also known as Wernicke’s aphasia, fluent aphasia, or sensory aphasia, is a type of aphasia traditionally associated with neurological damage to Wernicke’s area in the brain,...
, a language disorder that causes poor comprehension of speech and the production of fluent but incomprehensible sentences. A patient with Wernicke's aphasia cannot correct his own phonetic
Phonetics
Phonetics is a branch of linguistics that comprises the study of the sounds of human speech, or—in the case of sign languages—the equivalent aspects of sign. It is concerned with the physical properties of speech sounds or signs : their physiological production, acoustic properties, auditory...
errors and shows "anger and disappointment with the person with whom he is speaking because that person fails to understand him." This may be a result of brain damage to the posterior portion of the superior temporal gyrus
Superior temporal gyrus
The superior temporal gyrus is one of three gyri in the temporal lobe of the human brain, which is located laterally to the head, situated somewhat above the external ear.The superior temporal gyrus is bounded by:* the lateral sulcus above;...
, believed to contain representations of word sounds. With those representations destroyed, patients with Wernicke's aphasia are unable to monitor their mistakes. Other patients with Wernicke's aphasia are fully aware of their condition and speech inhibitions, but cannot monitor their condition, which is not the same as anosognosia and therefore cannot explain the occurrence of neologistic jargon.
Psychiatry
Although largely used to describe unawareness of impairment after brain injury or stroke, the term 'anosognosia' is occasionally used to describe the lack of insight shown by some people who suffer from a mental illness such as bipolar disorder or psychosisPsychosis
Psychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
. They do not have the insight to recognize that they suffer from a mental illness. There is evidence that schizophrenic anosognosia may be the result of frontal lobe damage.
Treatment
In regard to psychiatric patients, empirical studies verify that, for individuals with severe mental illnesses, lack of awareness of illness is significantly associated with both medication non-compliance and re-hospitalization. Fifteen percent of individuals with severe mental illnesses who refuse to take medication voluntarily under any circumstances may require some form of coercion to remain compliant because of anosognosia.One study of voluntary and involuntary inpatients confirmed that committed patients require coercive treatment because they fail to recognize their need for care. Predictably, the patients committed to the hospital had significantly lower measures of insight than the voluntary patients.
Anosognosia is also closely related to other cognitive dysfunctions that may impair the capacity of an individual to continuously participate in treatment. Other research has suggested that attitudes toward treatment can improve after involuntary treatment and that previously committed patients tend later to seek voluntary treatment.
In regard to anosognosia for neurological patients, no long-term treatments exist. As with unilateral neglect, caloric reflex testing (squirting ice cold water into the left ear) is known to temporarily ameliorate unawareness of impairment. It is not entirely clear how this works, although it is thought that the unconscious shift of attention
Attention
Attention is the cognitive process of paying attention to one aspect of the environment while ignoring others. Attention is one of the most intensely studied topics within psychology and cognitive neuroscience....
or focus caused by the intense stimulation of the vestibular system temporarily influences awareness. Most cases of anosognosia appear to simply 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).
See also
- AnosodiaphoriaAnosodiaphoriaAnosodiaphoria is a condition in which a person who suffers disability due to brain injury seems indifferent to the existence of their handicap. Anosophoria is specifically used in association with indifference to paralysis. It is a somatosensory agnosia, or a sign of neglect syndrome...
- Anton–Babinski syndrome
- Brain damageBrain damage"Brain damage" or "brain injury" is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors...
- ConfabulationConfabulationConfabulation is the process in which a memory is remembered falsely. Confabulations are indicative of a complicated and intricate process that can be led astray at any given point during encoding, storage, or recall of a memory. Two distinct types of confabulation are often distinguished...
- DenialDenialDenial is a defense mechanism postulated by Sigmund Freud, in which a person is faced with a fact that is too uncomfortable to accept and rejects it instead, insisting that it is not true despite what may be overwhelming evidence.The subject may use:* simple denial: deny the reality of the...
- Dunning–Kruger effect
- EgosyntonicEgosyntonicEgosyntonic is a psychological term referring to behaviors, values, feelings that are in harmony with or acceptable to the needs and goals of the ego, or consistent with one's ideal self-image....
- Introspection illusionIntrospection illusionThe introspection illusion is a cognitive illusion in which people wrongly think they have direct insight into the origins of their mental states, while treating others' introspections as unreliable...
- Oliver SacksOliver SacksOliver Wolf Sacks, CBE , is a British neurologist and psychologist residing in New York City. He is a professor of neurology and psychiatry at Columbia University, where he also holds the position of Columbia Artist...
- Unilateral neglect (also known as Hemispatial neglect)
- Vilayanur S. RamachandranVilayanur S. RamachandranVilayanur Subramanian "Rama" Ramachandran, born 1951, is a neuroscientist known for his work in the fields of behavioral neurology and visual psychophysics...
- Cerebral hypoxiaCerebral hypoxiaCerebral hypoxia refers to a reduced supply of oxygen to the brain. Cerebral anoxia refers to a complete lack of oxygen to the brain. There are four separate categories of cerebral hypoxia; in order of severity they are; diffuse cerebral hypoxia , focal cerebral ischemia, cerebral infarction, and...