Anosognosia And Dementia

  • Ka Yin ChanBSc Cognitive Neuroscience and Psychology, University of Manchester
  • Anna KellyMBBS Medicine & Surgery (UCL), BSc Biomedical Sciences (University of Manchester)
  • Ananthajith RajeshBSc Hons Biomedical Science, University of Edinburgh

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Overview 

Dementia 

Dementia refers to the inability to remember, think or make decisions. It is not a natural part of ageing and is often associated with different diseases, such as Parkinson’s disease, Alzheimer’s disease and Lewy body dementia. People with dementia often have difficulties creating new memories, retrieving long-term memory and recalling information from their memory. Risk factors for dementia include age, family history, race, poor heart health and traumatic brain injury.1

Anosognosia 

Anosognosia refers to the condition in which patients are not aware of their own disease or illness. It often has a huge impact on patients and their caregivers.2 

Understanding dementia 

Definition and types of dementia 

Dementia can be defined as any kind of cognitive impairment that negatively impacts one’s independent daily functioning, including in social settings, the workplace and at home. It is a syndrome caused by neurologic, neuropsychiatric and medical conditions. In the elderly, Alzheimer’s disease and Lewy body dementia are most common types of dementia. In the world, 7% of those aged 65 or above are diagnosed with dementia.

Traumatic brain injury and brain tumours are the primary causes of dementia in young adults. 

The common causes of dementia can be categorised into two groups, as below:

NeurodegenerativeNon-neurodegenerative 
Alzheimer’s diseaseVitamin deficiencies (e.g., B12, thiamine)
Lewy body dementiaChronic alcohol abuse
Vascular dementiaIntracranial masses (e.g., brain tumour)
Frontotemporal lobar degenerationTraumatic brain injury
Parkinson’s diseasePsychological illness (e.g., severe depression or anxiety)

Symptoms and progression of dementia

Early symptoms of dementia include: 

  • Loss of memory
  • Finding it hard to focus
  • Having difficulty completing daily tasks
  • Having trouble following a conversation
  • Difficulty with expressing themselves using the right words
  • Confusion about the time and place
  • Mood fluctuations

Different types of dementia have different symptoms. For example, people with dementia caused by Alzheimer’s disease often have difficulties in organisation and planning. On the other hand, vascular dementia is characterised by movement problems and muscle weakness. Lewy body dementia is associated with visual hallucinations and sleep disturbances, while frontotemporal lobar degeneration includes symptoms like personality changes and lack of social awareness. 

Progression of dementia leads to worsened cognitive impairment and hence requires care and attention at all times. People with advanced dementia experience more and worse problems in memory (like forgetting where they live), communication mobility and behaviour.

For example, some may lose the ability to speak, while some may lose the ability to walk and have to be in a wheelchair, or even become bedbound. In terms of behavioural problems, some may experience depressive and anxious episodes, become more aggressive and agitated, or develop hallucinations. Some may experience bladder and bowel incontinence or have reduced appetite and weight loss. 

Understanding anosognosia 

Definition of anosognosia 

People are said to be anosognosic when they are unaware or underestimate the impairment in sensory, perceptual, motor, affective or cognitive function caused by their condition.6 

Causes and mechanisms 

Neurological damage

Anosognosia often results from structural or functional damage to specific areas of the brain responsible for self-awareness, insight, and perception. This damage can be caused by strokes, traumatic brain injury, tumours, or degenerative diseases such as Alzheimer's disease.

Disruption of neural networks

The brain networks involved in self-awareness and perception are complex and interconnected. Disruptions in these neural networks, either due to damage or dysfunction, can lead to discrepancies between actual abilities and perceived abilities.

Frontal lobe dysfunction

The frontal lobes of the brain play a crucial role in self-monitoring, judgement and awareness. Damage to the frontal lobes, either through injury or disease, can impair an individual's ability to recognise their deficits or limitations.

Impaired insight processing

Anosognosia may also stem from deficits in the processing of sensory information, memory and cognitive evaluations. Individuals with dementia may struggle to integrate feedback from their environment or past experiences, leading to a distorted perception of their own abilities.

Psychological factors

In addition to neurological factors, psychological mechanisms can contribute to anosognosia. Defence mechanisms such as denial or minimisation may serve to protect an individual's sense of self-esteem or reduce anxiety about their condition.

Neurochemical imbalances

Changes in neurotransmitter systems, such as dopamine and serotonin, have been implicated in anosognosia. Disruptions in these systems may alter perception, mood and cognitive processing, contributing to a lack of awareness of one's condition.

Interaction with cognitive decline

In conditions like dementia, anosognosia often coexists with other cognitive deficits, such as memory loss and executive dysfunction. The severity and progression of these cognitive impairments can influence the degree of anosognosia experienced by an individual.

Individual variability

Anosognosia can vary widely among individuals with similar neurological conditions. Factors such as personality traits, coping strategies, social support and cultural influences may modulate the expression and severity of anosognosia.

How anosognosia manifests in dementia patients

Studies have discovered that anosognosia is manifested in approximately 10% of patients with mild dementia and 80% of patients with severe dementia. It is suggested that not only does the prevalence of anosognosia increase with the severity of dementia, it is also associated with neuropsychiatric symptoms, such as depression and anxiety.

It is also found that anosognosia is more common in Alzheimer’s disease and frontotemporal lobar degeneration dementia, given that the frontal lobes are involved regardless of age at the onset of dementia.7

Relationship between anosognosia and dementia 

Impact on treatment and caregiving 

Anosognosia increases difficulty with treatment. As the patients are not aware of their own health conditions and cognitive deficits, they may be less inclined to participate in treatment and rehabilitation to deal with the problems they face in their daily lives.

They may also experience more frequent falls as they are unaware of their own motor dysfunction. Health providers and caregivers need to be more attentive and provide constant care to patients in order to avoid injury.8 

Challenges in diagnosis and management

Anosognosia in dementia can be assessed in three ways:

  • Clinical rating
    • Clinicians estimate whether patients have anosognosia or not through questionnaire, semi-structured interview or observation. However, patients may present themselves in a socially desirable way, making them look like they are in denial of their symptoms. This could lead to misinterpretation and misdiagnosis of anosognosia 
  • Patient-caregiver discrepancies
    • This method compares the rating of functional performance provided by the patients themselves and by their caregivers. However, these ratings are subjective, leading to overestimation and underestimation from the patients and their caregivers respectively. The comparison may exaggerate the actual situation 
  • Prediction of performance discrepancies
    • Patients self-rate their performance on a task and the rating is compared against the actual performance score of the task. The degree of anosognosia is determined by the differences between the two scores. However, these tasks are often time-consuming and affected by personal factors like mood and personality3 

Nonetheless, there is no current standardised test or assessment for anosognosia. To formulate a treatment plan, a team of healthcare professionals from different fields is gathered together to assess the patient’s condition in every aspect and discuss ways to manage it. The team usually includes a neurologist, psychiatrist, mental health nurse, primary care physician and psychotherapist.8 

Although there is no treatment for anosognosia, vestibular stimulation was found to be conducive to improving the condition temporarily. If it persists, cognitive therapy may help improve patients’ understanding of their dysfunctions and therefore compensate for them in various ways.

Future directions and research 

Areas for further study 

As there are no standardised assessments for anosognosia, future research should focus on developing a test or questionnaire specialised for diagnosing anosognosia. Recently, there are more in-depth assessments developed, which assess multiple domains that dementia might have an impact on.

It is suggested that the Clinical Insight Rating Scale and the Abridged Anosognosia Questionnaire would be the best for diagnosing anosognosia. However, they both have their limitations. Future research should develop a modified version or even a new assessment to overcome these limitations for the diagnosis of anosognosia related to dementia. 

Summary

To summarise, anosognosia is fairly common in patients with dementia caused by diseases involving the frontal lobes. Patients with anosognosia are not aware of their own cognitive deficits caused by dementia. This makes the diagnosis of anosognosia difficult. Currently, there are no standardised assessments or treatments for anosognosia. However, cognitive therapy may help increase patients’ awareness of their problems. 

References

  1. What is dementia? | cdc [Internet]. 2022 [cited 2024 Apr 26]. Available from: https://www.cdc.gov/aging/dementia/index.html
  2. Memory loss and dementia | Alzheimer’s Society [Internet]. 2021 [cited 2024 Apr 26]. Available from: https://www.alzheimers.org.uk/about-dementia/symptoms-and-diagnosis/symptoms/memory-loss
  3. de Ruijter NS, Schoonbrood AMG, van Twillert B, Hoff EI. Anosognosia in dementia: A review of current assessment instruments. Alzheimers Dement (Amst) [Internet]. 2020 Sep 30 [cited 2024 Apr 26];12(1):e12079. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527687/
  4. Gale SA, Acar D, Daffner KR. Dementia. The American Journal of Medicine [Internet]. 2018 Oct 1 [cited 2024 Apr 26];131(10):1161–9. Available from: https://www.sciencedirect.com/science/article/pii/S0002934318300986
  5. nhs.uk [Internet]. 2023 [cited 2024 Apr 26]. Symptoms of dementia. Available from: https://www.nhs.uk/conditions/dementia/symptoms-and-diagnosis/symptoms/
  6. Pace A, Tanzilli A, Benincasa D. Chapter 10 - Prognostication in brain tumors. In: Miyasaki JM, Kluger BM, editors. Handbook of Clinical Neurology [Internet]. Elsevier; 2022 [cited 2024 Apr 26]. p. 149–61. (Neuropalliative Care, Part I; vol. 190). Available from: https://www.sciencedirect.com/science/article/pii/B9780323850292000014
  7. Tondelli M, Galli C, Vinceti G, Fiondella L, Salemme S, Carbone C, et al. Anosognosia in early- and late-onset dementia and its association with neuropsychiatric symptoms. Front Psychiatry [Internet]. 2021 May 13 [cited 2024 Apr 26];12:658934. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8155545/
  8. Acharya AB, Sánchez-Manso JC. Anosognosia. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 [cited 2024 Apr 26]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK513361/

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Ka Yin Chan

BSc Cognitive Neuroscience and Psychology, University of Manchester

She is a Neuroscience student with strong interest in clinical research and medical communications. She believes that the ever-growing field of scientific research is crucial for understanding health and hence improve it.

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