Anosognosia: when we do not perceive our disorders

“Pedro suffered a stroke a month ago. Due to this cardiovascular event, he suffered from hemiplegia which left the left side of his body paralyzed, unable to move his limbs. During a visit scheduled to his doctor, he performs a full scan, clearly indicating that Peter is still unable to move his left arm and leg, but Peter indicates that he has no physical problems and is moving normally, indicating with complete conviction that in fact, during the scan, he made all the movements that were indicated to him correctly ”.

This case reflects that Peter is convinced that his arm is moving normally, there is a clear difference between what he thinks he is doing and his actual performance. This is a case of a phenomenon known as anosognosia.

What is anosognosia?

By anosognosia we mean a particular subtype of agnosia, in which the patient is unable to recognize the existence of a functioning deficit even though it may be obvious to others. It is a lack of awareness of the disease limited to recognizing their own deficit, and the same individual may be able to detect the same problem in other people.

Anosognosia is not a disorder per se, but is classified as a symptom, such as it appears only associated with the existence of a disorder and informs us of its existence.

While the study of anosognosia is very common in the area of ​​hemiplegia treatment, anosognosia is not limited to this disorder, but can arise from a large number of brain lesions that should not be associated only to the problem of the motor system, but also to the perceptual (it is typical to observe its presence in patients with cortical blindness) or to other disorders, including psychiatric.

Detect anosognosia

In order to be able to diagnose anosognosia, it is necessary, in addition to the presence of the ignorance of the deficit, that it be denied by the patient, the fact that the deficit is evident in a neuropsychological evaluation, that it is recognized by relatives. and close circles, clinically significant interference with the patient’s life.

When evaluating this phenomenon, it should be borne in mind that it is necessary to distinguish when the patient does indeed present anosognosia and when he denies his problems as a coping strategy in the face of his loss. Despite this complication, some specific assessment tools have been created to assess anosognosia in which the ability and difficulty of performing specific tasks should be assessed.

Anosognosia is not an all-or-nothing phenomenon, and there may be cases in which the disorder is not recognized at all times, but also others in which patients recognize the existence of a problem after demonstrating the existence of deficits.

Why is this happening? Possible causes

Since this phenomenon was called anosognosia by Babinski in 1914, an attempt has been made to explain why this symptom occurs, Having several theories in this regard. The explanatory proposals are varied, emphasizing the existence of neurological or neuropsychological problems.

An example of this is Schachter’s theory called Dissociable Interactions and Conscious Experience, according to which there is an interaction between the systems in charge of conscious experience and those of the systems in charge of impaired function, which in case of injury or of malfunction they would. fail to properly integrate information, producing a conscious experience of action or functionality when not provided by the affected system.

Despite these generalities, the specific cause of anosognosia will depend on the type and location of the lesion and the problem causing it.

Some pictures in which this happens

As already mentioned, anosognosia is a symptom present in many different problems. Some of them are:

1. Hemiplegia

One of the most common disorders. In these cases, the patient often believes that he is performing movements that he is not actually performing and that he in fact has the conscious experience of performing them.

2. Cortical blindness

Many patients who have destroyed the occipital area of ​​the brain or the connections between it and the visual pathways (which impedes visual perception) insist that they are able to see normally, making exhaustive descriptions of this. that they think they visualize. Anosognosis also occurs in these cases.

3.lateral heminegligence

In this trouble, although the subject perceives the whole perceptual field, he neglects or does not attend to one of the visual hemicamps, Do not attend to the opposite side of the hemisphere in which he sustains the injury. He is clearly visible when asked to make copies of drawings: in these cases he only draws one of the halves and “forgets” to fill in the other part on the other side of an imaginary vertical line. In this context, it is common for the patient to be unaware of his problem, presenting with anosognosia

4. Dementia

Although in the early stages of dementia the patient is usually aware of the presence of his various problems, this knowledge does not occur in all or all dementias. In addition, as the disease progresses and the degenerative process continues its course, the individual tends to cease to be aware of it.

5. Schizophrenia

In some subtypes of schizophrenia, such as disorganized and catatonic, and especially during the acute phases of the disorder, it is common for the patient not to perceive the presence of their own difficulties, as in the case of using a disorganized, tangential, derailed or incoherent language.


Apart from those presented here, there are a very large number of disorders both mental and neurological which present with anosognosia, being an important symptom to take into account in the treatment of various problems.

Effects of this symptom

It should be remembered that the presence of this problem can lead to serious dangers.

The presence of anosognosia is a difficulty in following treatment or rehabilitation of the disorder causing it. It must be borne in mind that for a patient to be involved in their recovery, they must be motivated for it, which is difficult if they are not aware of the presence of a symptomatology. Thus, patients with anosognosia often underestimate or even deny the need for treatment, making it difficult for them to meet established prescriptions.

Outraged, ignorance of the problem can lead the subject to carry out actions likely to endanger his integrity and / or that of third parties. Examples of this could be an individual with lateral heminegligence (subjects who attend only one hemicampus, unable to see the left or right side of things for example) or with cortical blindness who truly believes they have their abilities retained and functional, who decide to take the car and drive.

Treatment of anosognosia

The treatment of anosognosia itself is complex. Usually, the symptom improves with treatment of the underlying cause of its onset, whether it is a mental or neurological disorder. However, at the clinical level, confrontational strategies are used.

In this sense, the confrontation with the existence of deficits must be progressive, gradually introducing the idea of ​​their existence. It is important to show not only the presence of deficits, but also the difficulties of everyday life.

Bibliographical references:

  • Babinski, J. (1918). Anosognosis. Rev Neurol (Paris). 31: 365-7.

  • Banys, R. and Perpiña, C. (2002). Psychopathological examination. Madrid: Synthesis.

  • Belloch, A., Bains, R. and Perpiñá, C. (2008) Psychopathology of perception and imagination. In A. Belloch, B. Sandín and F. Ramos (Eds.) Handbook of Psychopathology (2nd edition). Flight I, Madrid: McGraw Hill Interamericana

  • Bembibre, J. and Arnedo, M. (2012). Neuropsychology of the dorsolateral prefrontal cortex I. In: M. Arnedo, J. Bembibre and M. Triviño (coord.), Neuropsychology: Through Clinical Cases (pp. 177-188). Madrid: Editorial Mèdica Panamericana.

  • Bisiach E, Vallar G, Perani D, Papagno C, Berti A (1986). Ignorance of the disease after lesions of the right hemisphere: anosognosia for hemiplegia and anosognosia for hemianopia. Neuropsychology. 1986; 24 (4): 471-82.

  • Orfei, MD et al. (2007). Anosognosis for hemiplegia after stroke is a multifaceted phenomenon: a systematic review of the literature. Brain, 130, 3075-3090.

  • Ownsworth, T., and Clare, L. (2006). The association between consciousness deficits and the outcome of rehabilitation after acquired brain injury. Journal of Clinical Psychology, 26, 783-795.

  • Prigatano, GP (2009). Anosognosis: clinical and ethical considerations. Current Opinion in Neurology, 22, 606-611.

  • Prigatano, G. (2010). Research of anosognosis. Oxford University Press.

  • Schachter, DL (1992). Consciousness and awareness of memory and amnesia: critical issues. In the neuropsychology of consciousness. Milner and Rugg. Academic Press London

  • Tremont, G. and Alosco, ML (2010). Relationship between cognition and awareness of deficit in mild cognitive impairment. Int J Geriatr Psychiatry.

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