Anosognosia is a condition in which a person with a

disability Disability is the experience of any condition that makes it more difficult for a person to do certain activities or have equitable access within a given society. Disabilities may be cognitive, developmental, intellectual, mental, physical, ...

is cognitively unaware of having it due to an underlying physical or psychological (e.g., PTSD,

Stockholm syndrome Stockholm syndrome is a condition in which hostages develop a psychological bond with their captors. It is supposed to result from a rather specific set of circumstances, namely the power imbalances contained in hostage-taking, kidnapping, and ...

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social w ...

bipolar disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of Depression (mood), depression and periods of abnormally elevated Mood (psychology), mood that last from days to weeks each. If the elevat ...

dementia Dementia is a disorder which manifests as a set of related symptoms, which usually surfaces when the brain is damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, which negatively affe ...

) condition. Anosognosia can result from ''physiological damage'' to brain structures, typically to the parietal lobe or a diffuse lesion on the fronto-temporal-parietal area in the right hemisphere, and is thus a

neuropsychiatric disorder A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitt ...

. A deficit of self-awareness, it was first named by the neurologist Joseph Babinski in 1914. Phenomenologically, anosognosia has similarities to denial, which is a psychological defense mechanism; attempts have been made at a unified explanation. Anosognosia is sometimes accompanied by asomatognosia, a form of neglect in which patients deny ownership of body parts such as their limbs. The term is from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...

ἀ- ''a-'', 'without', νόσος ''nosos'', 'disease' and γνῶσις ''gnōsis'', 'knowledge'. It is also considered a disorder that makes the treatment of the patient more difficult, since it may affect negatively the

therapeutic relationship The therapeutic relationship refers to the relationship between a healthcare professional and a client or patient. It is the means by which a therapist and a client hope to engage with each other and effect beneficial change in the client. In psy ...

Causes

Relatively little has been discovered about the cause of the condition since its initial identification. Recent empirical studies tend to consider anosognosia a multi-componential syndrome or multi-faceted phenomenon. That is it can be manifested by failure to be aware of a number of specific deficits, including motor (

hemiplegia Hemiparesis, or unilateral paresis, is weakness of one entire side of the body ('' hemi-'' means "half"). Hemiplegia is, in its most severe form, complete paralysis of half of the body. Hemiparesis and hemiplegia can be caused by different med ...

), sensory (hemianaesthesia, hemianopia), spatial ( unilateral neglect), memory (

), and language (

receptive aphasia Wernicke's aphasia, also known as receptive aphasia, sensory aphasia or posterior aphasia, is a type of aphasia in which individuals have difficulty understanding written and spoken language. Patients with Wernicke's aphasia demonstrate fluent ...

) due to impairment of anatomo-functionally discrete monitoring systems. Anosognosia is relatively common following different causes of brain injury, such as stroke and traumatic brain injury; for example, anosognosia for

hemiparesis Hemiparesis, or unilateral paresis, is weakness of one entire side of the body ('' hemi-'' means "half"). Hemiplegia is, in its most severe form, complete paralysis of half of the body. Hemiparesis and hemiplegia can be caused by different med ...

(weakness of one side of the body) with onset of acute

stroke A stroke is a disease, medical condition in which poor cerebral circulation, blood flow to the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorr ...

is estimated at between 10% and 18%. However, it can appear to occur in conjunction with virtually any neurological impairment. It is more frequent in the acute than in the chronic phase and more prominent for assessment in the cases with right hemispheric lesions than with the left. Anosognosia is not related to global mental confusion,

cognitive flexibility Cognitive flexibility is an intrinsic property of a cognitive system often associated with the mental ability to adjust its activity and content, switch between different task rules and corresponding behavioral responses, maintain multiple con ...

, other major intellectual disturbances, or mere sensory/perceptual deficits. The condition does not seem to be directly related to sensory loss but 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 In physiology, the somatosensory system is the network of neural structures in the brain and body that produce the perception of touch (haptic perception), as well as temperature (thermoception), body position ( proprioception), and pain. It ...

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 The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting o ...

in which people seem unable to attend to, or sometimes comprehend, anything on a certain side of their body (usually the left). 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. This is consistent with the idea that the source of the problem relates to spatial representation of the body. For example, anosognosia for hemiplegia may occur with or without intact awareness of visuo-spatial unilateral neglect. This phenomenon of double dissociation can be an indicator of domain-specific disorders of awareness modules, meaning that in anosognosia, brain damage can selectively impact the self-monitoring process of one specific physical or cognitive function rather than a spatial location of the body. There are also studies showing that the maneuver of vestibular stimulation could temporarily improve both the syndrome of spatial unilateral neglect and of anosognosia for left hemiplegia. Combining the findings of hemispheric asymmetry to the right, association with spatial unilateral neglect, and the temporal improvement on both syndromes, it is suggested there can be a spatial component underlying the mechanism of anosognosia for motor weakness and that neural processes could be modulated similarly. There were some cases of anosognosia for right hemiplegia after left hemisphere damage, but the frequency of this type of anosognosia has not been estimated. Anosognosia may occur as part of

, a language disorder that causes poor comprehension of speech and the production of fluent but incomprehensible sentences. A patient with receptive aphasia cannot correct his own

phonetic Phonetics is a branch of linguistics that studies how humans produce and perceive sounds, or in the case of sign languages, the equivalent aspects of sign. Linguists who specialize in studying the physical properties of speech are phoneticians. ...

s errors and shows "anger and disappointment with the person with whom s/he is speaking because that person fails to understand her/him". This may be a result of brain damage to the posterior portion of the

superior temporal gyrus The superior temporal gyrus (STG) is one of three (sometimes two) 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 l ...

, believed to contain representations of word sounds. With those representations significantly distorted, patients with receptive aphasia are unable to monitor their mistakes. Other patients with receptive 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 with

anorexia nervosa Anorexia nervosa, often referred to simply as anorexia, is an eating disorder characterized by low weight, food restriction, body image disturbance, fear of gaining weight, and an overpowering desire to be thin. ''Anorexia'' is a term of Gre ...

. They do not seem to recognize that they have a mental illness. There is evidence that anosognosia related to schizophrenia may be the result of frontal lobe damage.

E. Fuller Torrey Edwin Fuller Torrey (born September 6, 1937), is an American psychiatrist and schizophrenia researcher. He is associate director of research at the Stanley Medical Research Institute (SMRI) and founder of the Treatment Advocacy Center (TAC), a n ...

, a psychiatrist and schizophrenia researcher, has stated that among those with schizophrenia and bipolar disorder, anosognosia is the most prevalent reason for not taking medications.

Diagnosis

Clinically, anosognosia is often assessed by giving patients an anosognosia questionnaire in order to assess their metacognitive knowledge of deficits. However, neither of the existing questionnaires applied in the clinics are designed thoroughly for evaluating the multidimensional nature of this clinical phenomenon; nor are the responses obtained via offline questionnaire capable of revealing the discrepancy of awareness observed from their online task performance. The discrepancy is noticed when patients showed no awareness of their deficits from the offline responses to the questionnaire but demonstrated reluctance or verbal circumlocution when asked to perform an online task. For example, patients with anosognosia for hemiplegia may find excuses not to perform a bimanual task even though they do not admit it is because of their paralyzed arms. A similar situation can happen to patients with anosognosia for cognitive deficits after traumatic brain injury when monitoring their errors during the tasks regarding their memory and attention (online emergent awareness) and when predicting their performance right before the same tasks (online anticipatory awareness). It can also occur among patients with dementia and anosognosia for memory deficit when prompted with dementia-related words, showing possible pre-attentive processing and implicit knowledge of their memory problems. Patients with anosognosia may also overestimate their performance when asked in first-person formed questions but not from a third-person perspective when the questions referring to others. When assessing the causes of anosognosia within stroke patients, CT scans have been used to assess where the greatest amount of damage is found within the various areas of the brain. Stroke patients with mild and severe levels of anosognosia (determined by response to an anosognosia questionnaire) have been linked to lesions within the temporoparietal and

thalamic The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, ...

regions, when compared to those who experience moderate anosognosia, or none at all. In contrast, after a stroke, people with moderate anosognosia have a higher frequency of lesions involving the

basal ganglia The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an ext ...

, compared to those with mild or severe anosognosia.

Treatment

In regard to anosognosia for neurological patients, no long-term treatments exist. As with unilateral neglect,

caloric reflex testing In medicine, the caloric reflex test (sometimes termed vestibular caloric stimulation) is a test of the vestibulo-ocular reflex that involves irrigating cold or warm water or air into the external auditory canal. This method was developed by Rob ...

(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 is the behavioral and cognitive process of selectively concentrating on a discrete aspect of information, whether considered subjective or objective, while ignoring other perceivable information. William James (1890) wrote that "Att ...

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 patients to adjust for their inoperable limbs (though it is believed that these patients still are not "aware" of their disability). Another commonly used method is the use of feedback – comparing clients' self-predicted performance with their actual performance on a task in an attempt to improve insight. Neurorehabilitation is difficult because, as anosognosia impairs the patient's desire to seek medical aid, it may also impair their ability to seek rehabilitation. A lack of awareness of the deficit makes cooperative, mindful work with a therapist difficult. In the

acute Acute may refer to: Science and technology * Acute angle ** Acute triangle ** Acute, a leaf shape in the glossary of leaf morphology * Acute (medicine), a disease that it is of short duration and of recent onset. ** Acute toxicity, the adverse ef ...

phase, very little can be done to improve their awareness, but during this time, it is important for the therapist to build a therapeutic alliance with patients by entering their phenomenological field and reducing their frustration and confusion. Since severity changes over time, no single method of treatment or rehabilitation has emerged or will likely emerge. 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 Coercion () is compelling a party to act in an involuntary manner by the use of threats, including threats to use force against a party. It involves a set of forceful actions which violate the free will of an individual in order to induce a des ...

to remain compliant because of anosognosia. Coercive psychiatric treatment is a delicate and complex legal and ethical issue, but under certain circumstances, such as for individuals with schizophrenia and anosognosia, it can be justified. One study of voluntary and involuntary inpatients confirmed that committed patients require coercive treatment because they fail to recognize their need for care. 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.

References

External links

{{Medical resources , ICD10 = {{ICD10, R, 41, 8, r, 40 , ICD9 = {{ICD9, 780.9 , ICDO = , OMIM = , DiseasesDB = , MedlinePlus = , eMedicineSubj = , eMedicineTopic = Agnosia Dementia Stroke Symptoms and signs of mental disorders