Continuing Education Activity

Anosognosia is a neurological condition in which the patient is unaware of their neurological deficit or psychiatric condition. It is associated with mental illness, dementia, and structural brain lesion, as is seen in right hemisphere stroke patients. It can affect the patient’s conscious awareness of deficits involving judgment, emotions, memory, executive function, language skills, and motor ability. This activity examines when this condition should be considered and the differential diagnosis for this condition. This activity highlights the role of the interprofessional team in caring for patients with this condition.

Objectives:

• Identify the most common etiology of anosognosia in patients with neurological and psychiatric disorders.
• Describe the evaluation of patients with anosognosia.
• Outline the treatment and management options available for patients with anosognosia.
• Explain interprofessional team strategies for evaluating, managing, and educating patients and their families about anosognosia.

Access free multiple choice questions on this topic.

Introduction

Anosognosia is a neuropsychiatric condition in which one is unconsciously in denial and unaware of an apparent disability or deficit. The French neurologist, Joseph Babinski, first described anosognosia when highlighting the obliviousness of those afflicted with left hemiplegia in 1914.[1] Anosognosia can manifest transdiagnostically as it is extant in both psychiatric and neurologic disorders. Most often, it precipitates in the setting of structural damage, from ischemic strokes, in the right parietal cortex. It also serves as a psychiatric construct for describing a patient's lack of insight.[2]

Etiology

Typically, as mentioned in the introduction, anosognosia manifests as a neurological sequela following an injury or lesion to the right parietal lobe; however, the 2 are not mutually exclusive, as anosognosia can occur with temporoparietal, thalamic, or basal ganglia lesions, as well as in psychiatric disorders. The exact etiology of anosognosia is unknown, but it is likely due to a derangement of the anatomical or functional monitoring unit that mediates the conscious awareness of deficits. The most likely pathophysiologic mechanism is that the brain lesion causing anosognosia disrupts neurocognitive and secondary integration areas.[3] Structural and functional regions under investigation include the prefrontal cortex (involved in working memory, self-monitoring, and organization), the insular cortex (associated with the salience network, emotional processing, and error awareness), and the default mode network (characterized by connectivity among the prefrontal, parietal, and cingulate cortices). Damage to these areas can lead to a lack of conscious awareness of the loss of cognitive or sensorimotor function.

Epidemiology

Anosognosia can occur after acute brain injuries such as strokes or traumatic brain injuries, and can also occur in the absence of any putative brain injury. In stroke patients with hemiparesis, the incidence of anosognosia is 10% to 18%.[4] The term anosognosia can also refer to the lack of awareness seen in psychiatric conditions when patients deny or minimize psychiatric symptoms. It is estimated that 50-90% of patients with schizophrenia and 40% of patients with bipolar disorder demonstrate anosognosia or a severe lack of insight.[5] In the setting of neurocognitive disease, 60% of patients with mild cognitive impairment[6] and 81% of patients with Alzheimer dementia appear to have some form of anosognosia; patients suffering from these conditions deny or minimize their memory impairment.[7]

Pathophysiology

Patients with anosognosia due to brain injury often exhibit a lack of awareness of hemiparesis, hemisensory deficits, memory deficits, and language deficits. Patients may be unaware of 1 deficit while recognizing others. Anosognosia can co-occur with somatosensory neglect (asomatognosia), which also localizes to the right parietal lobe. The latter consists of the patient's denial that part of their body belongs to them. Although anosognosia usually accompanies a right parietal, temporoparietal, thalamic, or basal ganglia lesion, recent studies suggest that the deficit sometimes can relate to non-structural changes. These changes disrupt connectivity among different parts of the brain.[8] The fundamental neurophysiologic or psychopathologic problem in anosognosia relates probably to an inability of the patient to update their self-image. Because of a brain lesion or illness-related dysfunction, the patient cannot incorporate new information about their deficits into their self-image. Therefore, they deny their illness or deficit or downplay its significance.

History and Physical

Typically, health professionals diagnose anosognosia at the bedside by assessing the patient’s knowledge and insight into their symptoms. In subtle cases, it takes time and a lengthy conversation with the patient to uncover anosognosia, as patients may offer semi-logical explanations for not being able to perform activities on the affected side. In the setting of dementia, patients do not acknowledge or minimize their memory deficits. In the setting of mental illness, patients rationalize aberrant behavior or psychiatric symptoms and often confabulate (ie, unconsciously prevaricate). This involves creating a false answer or response by combining real and imagined details.

Evaluation

When anosognosia is due to structural brain damage, neuroradiological findings typically show damage to the right parietal or right temporoparietal region. Less common are lesions in the thalamus, basal ganglia, or left parietal region. Neuroimaging in dementia typically shows more global brain atrophy. Neuroimaging in psychiatric disorders usually shows non-specific findings.

There are publications on an anosognosia rating scale, which rates the level of unawareness of patients with dementia suffering from this condition:

1. Patients easily admit to memory loss.
2. Patients admit, sometimes inconsistently, to a small amount of memory loss.
3. Patients are unaware of any memory impairment.
4. Patients angrily insist that no memory problem exists.

Treatment / Management

There is no specific treatment for anosognosia, but vestibular stimulation appears to temporarily improve the condition. This maneuver probably temporarily influences awareness of the neglected side. Where anosognosia persists, cognitive therapy can help patients better understand and compensate for their deficit.

Differential Diagnosis

Anosognosia differs from denial, a psychological defense mechanism that involves avoiding or rejecting information that provokes stress or pain. With denial, the patient may acknowledge a deficit but minimize its consequences and avoid treatments aimed at remedying it. Anosognosia also differs from a more global derangement, such as encephalopathy, where there may be problems with wakefulness and attention. It differs from other deficits, such as visual, sensory, and cognitive deficits, which limit patients' ability to recognize their deficits.

Prognosis

When anosognosia is due to a focal structural lesion of the brain, it typically resolves over time, though it can persist in the long term. When anosognosia is due to mental illness or dementing illness, it may persist and lead to poor compliance with medication regimens.

Complications

Anosognosia can impair rehabilitation and recovery because patients who lack awareness of a deficit may show less inclination to take part in rehabilitation therapy to tackle the neurological dysfunction. Patients with anosognosia also may suffer more frequent falls due to their lack of awareness of their deficits. Healthcare providers may need to take safety precautions as they see fit to avoid injury.

Postoperative and Rehabilitation Care

Recently, A.R. Egbert described an ethical framework for involving patients with anosognosia in their rehabilitation.[9] Rehabilitation specialists must always consider this condition because it may affect the outcome of their treatment plan.

Deterrence and Patient Education

Education on how to deal with and help avoid problems related to anosognosia for patients and family members of patients with this dysfunction is of utmost importance, and lack of collaboration from the sufferer is typical due to the patient's failure to acknowledge or minimize their condition. Issues such as driving, handling money, and walking without help may become areas of conflict. It is important to conduct a thorough safety evaluation to prevent injury to a patient with anosognosia. Simplifying tasks, maintaining a positive approach, showing concern and empathy, and providing a structured environment are helpful to avoid negative outcomes.

Pearls and Other Issues

It is very important for emergency medicine clinicians to know about anosognosia. For example, in the setting of acute stroke, the timing of symptom onset is crucial to the administration of thrombolytic therapy. If the patient is unaware of their deficit, they may not give accurate information on the exact time of stroke symptom onset. In this situation, collateral history from a family member is crucial to making an informed treatment decision.

Enhancing Healthcare Team Outcomes

Managing anosognosia is very difficult. Because there are many causes, management is led by an interprofessional team that includes a neurologist, psychiatrist, mental health nurse, primary care physician, and psychotherapist. There is no specific treatment for anosognosia, but vestibular stimulation appears to temporarily improve the condition. This maneuver probably temporarily influences awareness of the neglected side. Where anosognosia persists, cognitive therapy can help patients better understand and compensate for their deficit. If the cause is a stroke, dementia, or a mass lesion, the prognosis in most cases is poor. If the cause is related to a mental health disorder, the condition leads to difficulty in medication compliance. The overall quality of life is poor.[10]

Review Questions

• Access free multiple choice questions on this topic.
• Click here for a simplified version.
• Comment on this article.

References

1.

Prigatano GP. Anosognosia and patterns of impaired self-awareness observed in clinical practice. Cortex. 2014 Dec;61:81-92. [PubMed: 25481467]

2.

Orfei MD, Caltagirone C, Spalletta G. The evaluation of anosognosia in stroke patients. Cerebrovasc Dis. 2009;27(3):280-9. [PubMed: 19202333]

3.

Ptak R, Lazeyras F. Functional connectivity and the failure to retrieve meaning from shape in visual object agnosia. Brain Cogn. 2019 Apr;131:94-101. [PubMed: 30591372]

4.

Baier B, Karnath HO. Incidence and diagnosis of anosognosia for hemiparesis revisited. J Neurol Neurosurg Psychiatry. 2005 Mar;76(3):358-61. [PMC free article: PMC1739568] [PubMed: 15716526]

5.

Fennig S, Everett E, Bromet EJ, Jandorf L, Fennig SR, Tanenberg-Karant M, Craig TJ. Insight in first-admission psychotic patients. Schizophr Res. 1996 Dec 15;22(3):257-63. [PubMed: 9000323]

6.

Vogel A, Stokholm J, Gade A, Andersen BB, Hejl AM, Waldemar G. Awareness of deficits in mild cognitive impairment and Alzheimer's disease: do MCI patients have impaired insight? Dement Geriatr Cogn Disord. 2004;17(3):181-7. [PubMed: 14739542]

7.

Turró-Garriga O, Garre-Olmo J, Calvó-Perxas L, Reñé-Ramírez R, Gascón-Bayarri J, Conde-Sala JL. Course and Determinants of Anosognosia in Alzheimer's Disease: A 12-Month Follow-up. J Alzheimers Dis. 2016;51(2):357-66. [PubMed: 26890611]

8.

Smith AJ, Campbell RW, Harrison PK, Harrison DW. Functional cerebral space theory: Towards an integration of theory and mechanisms of left hemineglect, anosognosia, and anosodiaphoria. NeuroRehabilitation. 2016;38(2):147-54. [PubMed: 26889731]

9.

Egbert AR. A Framework for Ethical Decision Making in the Rehabilitation of Patients with Anosognosia. J Clin Ethics. 2017 Spring;28(1):57-66. [PubMed: 28436930]

10.

Abela E, Missimer JH, Pastore-Wapp M, Krammer W, Wiest R, Weder BJ. Early prediction of long-term tactile object recognition performance after sensorimotor stroke. Cortex. 2019 Jun;115:264-279. [PubMed: 30875614]

Disclosure: Aninda Acharya declares no relevant financial relationships with ineligible companies.

Disclosure: Juan Carlos Sánchez-Manso declares no relevant financial relationships with ineligible companies.