Major Neurocognitive Disorder, Dementia

Major Neurocognitive Disorder, often referred to as Dementia, is considered a syndrome. In medical terms, a syndrome is a collection of symptoms and signs associated with a specific health-related condition that often occur together. Major Neurocognitive Disorder is categorised as a significant cognitive decline from a previous level of performance in one or more cognitive domains. These domains include complex attention, executive function, learning and memory, language, perceptual-motor, and social cognition. The decline in these domains must be substantial enough to interfere with independence in everyday activities and must not be exclusively during the course of a delirium or be better explained by another mental disorder.

1. Aetiology: The DSM-5 recognises various aetiologies for Major Neurocognitive Disorder, such as Alzheimer’s disease, frontotemporal lobar degeneration, Lewy body disease, vascular disease, traumatic brain injury, substance/medication use, HIV infection, prion disease, Parkinson’s disease, Huntington’s disease, and other medical conditions or multiple etiologies. The specific type of Major Neurocognitive Disorder is diagnosed based on the underlying cause.
2. Symptoms: Symptoms vary depending on the underlying cause, but generally include memory impairment, difficulties with language (aphasia), difficulty in recognising or identifying objects (agnosia), impaired ability to execute motor activities (apraxia), and impaired executive functions (such as planning, organising, sequencing, abstracting).
3. Progression and Severity: Major Neurocognitive Disorder can be progressive, static, or remitting. The DSM-5 outlines criteria for determining the severity of the disorder: mild, moderate, or severe, based on the level of assistance required for everyday activities.
4. Differential Diagnosis: It’s essential to differentiate Major Neurocognitive Disorder from normal age-related cognitive decline, mild neurocognitive disorder, delirium, mental disorders (such as major depressive disorder or schizophrenia), and effects of a substance.
5. Psychological Impact: Individuals with Major Neurocognitive Disorder may experience depression, anxiety, apathy, irritability, and other behavioural or psychological symptoms. The disorder also significantly impacts caregivers, often leading to caregiver stress or burnout.
6. Management: While there is no cure for most causes of Major Neurocognitive Disorder, treatment focuses on managing symptoms, slowing the progression of the disorder, and improving quality of life. This may include pharmacological interventions, cognitive and behavioural therapies, and support for caregivers.
7. Ethical and Legal Considerations: As the disorder progresses, issues related to consent, capacity, and legal guardianship may arise. Ethical considerations regarding the care and autonomy of individuals with Major Neurocognitive Disorder are also paramount.

Dementia VS Major Neurocognitive Disorder:

Dementia is an umbrella term used to describe a set of symptoms that negatively affect cognitive functions, such as memory, thinking, and social abilities, to an extent that it interferes with daily functioning. Dementia is not a specific disease; it’s a general term that covers a wide range of specific medical conditions, including Alzheimer’s disease.

Major Neurocognitive Disorder is also an umbrella term. It’s used to describe a range of cognitive impairments which are significant enough to interfere with independence and daily activities. This term encompasses conditions like Alzheimer’s disease, frontotemporal dementia, Lewy body dementia, and vascular dementia, among others. Each of these conditions has its own unique characteristics and causes, but they all fall under the broad category of Major Neurocognitive Disorder because they significantly impact cognitive functions such as memory, attention, language, and problem-solving skills. Between “Dementia” and “Major Neurocognitive Disorder” Major Neurocognitive Disorder is the preferred terminology in a clinical setting because it is seen as more precise and less stigmatising than the term dementia. Major Neurocognitive Disorder encompasses a range of cognitive deficits, including memory impairment, language difficulties, impaired ability to focus, impaired reasoning or problem-solving skills, and impaired visual perception. The term allows for a more specific diagnosis based on the type and severity of cognitive impairment.

“Dementia,” on the other hand, is a more traditional term that has been used for a longer time. It is often used in general and older medical literature. Dementia typically refers to a decline in mental ability severe enough to interfere with daily life, often due to Alzheimer’s disease or other specific diseases. While still widely used, especially in general conversations and in some medical contexts, there is a growing preference for the term “Major Neurocognitive Disorder” in clinical and research settings for its specificity and sensitivity.

Major Neurocognitive Disorder, also known as dementia, encompasses several subtypes, each characterised by distinct symptoms and underlying causes. Here are the major subtypes:

1. Alzheimer’s Disease: The most common form of dementia, characterised by memory loss, disorientation, and behavioural changes. It’s believed to result from abnormal build-up of proteins in and around brain cells.
2. Vascular Neurocognitive Disorders (Vascular Dementia): Caused by reduced blood flow to the brain, often due to strokes or other conditions affecting blood vessels. This leads to problems with planning, judgement, and memory.
3. Frontotemporal Disorders (Frontotemporal Dementia): Involves damage to the frontal and/or temporal lobes of the brain, affecting personality, behaviour, and language. It includes subtypes like behavioural variant frontotemporal dementia, primary progressive aphasia, and more.
4. With Lewy Bodies: A type of dementia characterised by abnormal deposits of a protein called alpha-synuclein in the brain. Symptoms include visual hallucinations, fluctuating alertness, and Parkinsonian motor symptoms.
5. Lewy Bodies: These are abnormal aggregates of protein that develop inside nerve cells, contributing to several neurodegenerative diseases, including Parkinson’s disease and dementia with Lewy bodies.
6. Neurocognitive Disorder due to HIV Infection: Cognitive impairment that arises as a direct result of HIV infection, affecting memory, concentration, and problem-solving skills.
7. Prion Disease: Rare, fatal neurodegenerative disorders caused by abnormally folded proteins in the brain. They lead to rapid cognitive and physical decline.
8. Parkinson’s Disease: Primarily a movement disorder, it can also lead to cognitive changes, particularly in later stages, due to brain changes affecting motor control. Cognition symptoms like memory and problem-solving difficulties can arise.
9. Mixed Dementia: Refers to the presence of characteristics of more than one type of dementia simultaneously, such as Alzheimer’s disease and vascular dementia.
10. Normal Pressure Hydrocephalus: Caused by the build-up of cerebrospinal fluid in the brain. Symptoms include difficulty walking, memory loss, and inability to control urination.
11. Huntington’s Disease: A progressive brain disorder caused by a single defective gene. Symptoms include abnormal involuntary movements, a severe decline in thinking and reasoning skills, and irritability.
12. Creutzfeldt-Jakob Disease: A rare, rapidly fatal disorder that impairs memory and coordination, and causes behaviour changes.
13. Wernicke-Korsakoff Syndrome: A chronic memory disorder caused by severe deficiency of thiamine (vitamin B-1), most commonly due to alcohol misuse.
14. Neurocognitive Disorder Due to Another Medical Condition: Cognitive impairments that are directly attributable to another medical condition not covered by the other categories.
15. Neurocognitive Disorder Due to Multiple Aetiologies: This occurs when cognitive impairment is due to more than one medical cause.

Each subtype of Major Neurocognitive Disorder may have distinct treatment approaches, emphasising the importance of accurate diagnosis and specialised care. The DSM-5’s approach to Major Neurocognitive Disorder emphasises a comprehensive evaluation of the individual’s cognitive deficits, their impact on everyday functioning, and the likely underlying aetiology, allowing for a nuanced understanding and tailored management of the disorder.