Dementia and Major Neurocognitive Disorders: Assessment, Types and Management

Dementia is an acquired decline in memory and/or other cognitive abilities that interferes with independence, relationships and everyday activities. It is not a normal part of ageing. Modern classifications also use major neurocognitive disorder; mild neurocognitive disorder describes measurable decline with preserved independence. Dementia is a clinical syndrome with many causes, and mixed pathology is common.

Learning objectives

• Define dementia/major neurocognitive disorder and distinguish it from normal ageing, delirium, depression and mild cognitive impairment.
• Recognise Alzheimer, vascular, Lewy-body, frontotemporal, Parkinson-related, HIV-associated and mixed patterns.
• Take a collateral history, assess cognition and function, investigate reversible contributors and formulate a differential.
• Manage cognition, behavioural symptoms, safety, capacity, safeguarding and caregiver strain.
• Explain indications, contraindications, adverse effects and monitoring of cognitive medicines.

1. Clinical significance of cognitive change

2. Common causes and patterns

Alzheimer disease

Usually begins with gradually progressive episodic-memory difficulty, followed by language, visuospatial, executive and functional decline. Later stages involve dependence, behavioural symptoms, dysphagia and communication difficulty.

Vascular cognitive impairment

May follow strokes or small-vessel disease. Stepwise or gradual progression, executive dysfunction, slowed processing, gait change, focal signs and vascular risk factors are clues. Mixed Alzheimer–vascular disease is common.

Dementia with Lewy bodies and Parkinson disease dementia

Fluctuating cognition, well-formed visual hallucinations, REM sleep behaviour disorder, parkinsonism, falls and autonomic symptoms suggest Lewy-body disease. Cognitive decline after established Parkinson disease suggests Parkinson disease dementia. Neuroleptic sensitivity is important.

Frontotemporal dementia

Often presents earlier with disinhibition, apathy, loss of empathy, compulsions, dietary change or progressive language impairment while memory may be relatively preserved early. It may be mistaken for depression, mania or personality disorder.

HIV-associated and other infectious disorders

Consider HIV-associated neurocognitive disorder, neurosyphilis, TB, cerebral malaria, cryptococcal disease and other infections according to symptoms, immune status and local epidemiology. Assess adherence, opportunistic disease and interactions.

Reversible or contributing causes

• Delirium, depression, sleep apnoea, pain and sensory impairment.
• Anticholinergic, sedative, opioid or polypharmacy effects.
• Thyroid disease, B12/folate deficiency, anaemia, renal/hepatic disease and electrolyte abnormalities.
• Alcohol/drugs, head injury, seizures, normal-pressure hydrocephalus, tumour and autoimmune disease.

3. History and collateral assessment

• Onset/course: first sign, rate of progression, stepwise change, fluctuation and recent deterioration.
• Domains: memory, attention, language, visuospatial ability, planning, judgement, social cognition and orientation.
• Function: finances, cooking, shopping, transport, telephone, work, medicines, hygiene, continence, feeding and mobility.
• Behaviour/mood: apathy, depression, anxiety, agitation, aggression, hallucinations, delusions, wandering, sleep and appetite.
• Medical and exposure history: strokes, seizures, Parkinsonism, head injury, HIV/TB, vascular risk, alcohol, medicines, herbal products and family history.
• Social context: housing, food, finances, caregiver capacity, abuse, neglect, isolation, spiritual beliefs and access to follow-up.

4. Examination and cognitive assessment

Record vitals, weight, nutrition, hydration, hearing, vision, gait, falls, neurological signs and parkinsonism. Perform a full mental state examination and assess attention, registration, delayed recall, recognition, executive function, language, abstraction and visuospatial skills. MoCA, MMSE or a validated local tool can establish a baseline; document language, education, sensory impairment, interpreter use and fatigue. A score does not diagnose dementia or determine capacity alone.

5. Investigations

• Full blood count, electrolytes/urea/creatinine, calcium, glucose, liver function and urinalysis.
• Thyroid function, B12/folate, HIV/syphilis testing when indicated by symptoms and consent, and malaria/TB or other infection tests according to local epidemiology.
• Medication/substance review, oxygenation and ECG where cardiac or medicine risk exists.
• CT/MRI for rapid or young onset, focal signs, seizures, gait disorder, head injury, atypical progression or diagnostic uncertainty.
• EEG for episodic altered awareness or unexplained fluctuations; lumbar puncture, autoimmune or genetic tests only when the clinical phenotype justifies specialist assessment.

6. Management goals

1. Treat reversible contributors.
2. Preserve independence, dignity, communication and meaningful activity.
3. Reduce distress without unnecessary sedation or restraint.
4. Prevent falls, delirium, medication harm, malnutrition, pressure injury and caregiver breakdown.
5. Support the person and family through diagnosis, progression and end-of-life planning.

7. Non-drug management

• Predictable routine, orientation board, good lighting, clocks and familiar objects.
• Glasses, hearing aids, dentures, preferred language and one-step communication.
• Exercise, meaningful activity, music, reminiscence, social contact and occupational therapy.
• Manage pain, constipation, urinary symptoms, sleep, nutrition, hydration, dental and visual problems.
• Use calm reassurance and redirection rather than arguing; identify triggers for wandering or agitation.
• Offer caregiver education, respite, support groups, home-based services and community resources.

8. Cognitive medicines

Cholinesterase inhibitors and memantine provide symptomatic benefit for selected patients; they do not cure dementia. Confirm indication, discuss realistic goals and review benefit and harm.

Monitor cognition/function, weight, pulse, falls, syncope, GI effects, adherence, mood, sleep and caregiver observations. Stop or change if harm outweighs meaningful benefit.

9. Behavioural and psychological symptoms

Agitation, aggression, psychosis, wandering, shouting, disinhibition and sleep change require a search for pain, infection, delirium, constipation, urinary retention, hunger, fear, overstimulation, unfamiliar carers, medicine effects or unmet communication needs.

1. Describe the behaviour, time, trigger, consequence and risk.
2. Check delirium, physical discomfort, medicines and environment.
3. Use reassurance, meaningful activity, environmental change and caregiver strategies.
4. Consider an antipsychotic only for severe distress or risk when non-drug measures fail, after discussing increased stroke and mortality risk and setting a short review.

If a specialist decides an antipsychotic is necessary, use the lowest dose and shortest duration. Educational examples may include risperidone 0.25–0.5 mg once or twice daily or quetiapine 12.5–25 mg at night, but local protocols and frailty, renal/hepatic function, Parkinsonism, Lewy-body disease, QT risk and consent govern decisions. Avoid routine use and avoid dopamine blockers in suspected Lewy-body dementia unless a senior specialist directs it.

10. Safety, capacity and safeguarding

• Assess medication errors, falls, wandering, cooking/fire, road safety, exploitation, financial abuse and access to pesticides or weapons.
• Capacity is decision-specific: support communication and assess understanding, retention, weighing and communication for each decision.
• Plan future care early: trusted contacts, advance preferences, finances, property, transport and end-of-life wishes according to local law.
• Ask privately about neglect, coercion or abuse; cognitive impairment increases vulnerability.
• Driving or motorcycle use requires risk assessment and local legal guidance; review as cognition changes.

11. Common complications

12. Communicating the diagnosis

Ask what the person wants to know and who they want present. Explain that dementia is a syndrome with different causes, some contributors are treatable, and support continues after diagnosis. Give written information, follow-up contacts and a plan for worsening confusion, falls, medication problems or caregiver exhaustion.

13. Worked cases

Progressive memory loss

A 68-year-old repeatedly forgets appointments, leaves the cooker on and needs help with finances. Collateral history confirms a two-year decline. Assess cognition/function, examine neurological signs, investigate reversible contributors, review medicines, consider imaging and create a person-centred plan.

Sudden deterioration in established dementia

A person with dementia becomes drowsy and inattentive with fever. Treat as delirium superimposed on dementia: check glucose, oxygenation, infection, hydration, medicines, pain, retention and constipation.

Visual hallucinations and parkinsonism

Fluctuating attention, formed visual hallucinations, falls and rigidity suggest Lewy-body dementia. Seek specialist advice before dopamine-blocking medicines.

14. Quick self-test

1. How does dementia differ from delirium?
2. Name four cognitive domains besides memory.
3. What is the role of collateral history?
4. List five reversible contributors.
5. When is brain imaging particularly important?
6. What are the usual donepezil starting and maximum doses?
7. Why are antipsychotics risky in dementia?
8. What must be assessed before diagnosing BPSD?
9. How is capacity assessed?
10. What should follow diagnosis?

Answers

1. Dementia is usually progressive and interferes with independence; delirium is acute/fluctuating with impaired attention and needs urgent medical assessment.
2. Attention, language, executive function, visuospatial ability, social cognition and orientation.
3. It establishes baseline, onset, progression, function and safety when recall is unreliable.
4. Delirium, depression, medicines, sleep apnoea, thyroid/B12 disease, infection, substance use, sensory impairment, renal/hepatic disease and hydrocephalus.
5. Rapid/young onset, focal signs, seizures, gait disorder, head injury, atypical progression, cancer or diagnostic uncertainty.
6. Donepezil commonly starts at 5 mg nightly and may increase to 10 mg after several weeks if tolerated.
7. They increase stroke and mortality risk and can worsen Parkinsonism, sedation, falls and QT risk.
8. Pain, infection, delirium, constipation, urinary retention, medication effects, environmental triggers and unmet needs.
9. For the specific decision assess understanding, retention, weighing and communication, supporting decision-making first.
10. Explanation, written information, reversible-cause plan, treatment/support options, safety and safeguarding assessment, caregiver support and follow-up.

References and further reading

• NICE: Dementia assessment, management and support.
• WHO: Dementia fact sheet.
• WHO mhGAP: diagnosis of dementia.
• WHO Global Dementia Observatory: diagnosis, treatment and care.
• WHO: ICD-11 clinical descriptions and diagnostic requirements.
• Use Uganda Ministry of Health and local hospital guidance for HIV-associated disorders, medicines, safeguarding, capacity, referral and community support.