Dementia is a condition that causes progressive and irreversible impairment in memory, cognition, personality and communication. It is particularly associated with older age. Early-onset dementia refers to when the symptoms start before aged 65.
Types of Dementia
Mild cognitive impairment involves a deficit in cognition and memory that is greater than expected with age but not significant enough for a diagnosis of dementia. People with mild cognitive impairment can usually live independently.
Alzheimers dementia is the most common type of dementia. The underlying pathophysiology involves brain atrophy, amyloid plaques, reduced cholinergic activity and neuroinflammation.
Vascular dementia is the second most common type. It is caused by vascular damage and impaired blood supply to the brain. Risk factors are the same as other cardiovascular diseases (e.g., hypertension, diabetes and smoking).
Dementia with Lewy bodies is a type of dementia associated with features of Parkinsonism. It causes a progressive cognitive decline. There are associated symptoms of visual hallucinations, delusions, REM sleep disorders and fluctuating consciousness.
Frontotemporal dementia is a rarer type that notably affects people at a younger age (starting aged 40-60). It mainly affects the frontal and temporal lobes. The initial presentation typically involves abnormalities in behaviour, speech and language. It can be familial (inherited).
Differential Diagnosis
Many conditions can cause cognitive impairment, memory impairment or personality changes.
Medications with an anticholinergic effect, particularly:
- Anticholinergic urological drugs (e.g., oxybutynin, solifenacin and tolterodine)
- Antihistamines (e.g., chlorphenamine and promethazine)
- Tricyclic antidepressants (e.g., amitriptyline)
Psychiatric conditions include:
- Depression
- Psychosis
- Delirium (e.g., secondary to infection)
Neurological conditions include:
- Brain tumours (particularly affecting the frontal lobes)
- Parkinson’s disease
- Huntington’s disease
- Progressive supranuclear palsy
Endocrine conditions include:
- Hypothyroidism
- Adrenal insufficiency
- Cushing’s syndrome
- Hyperparathyroidism (causing hypercalcaemia)
Nutritional deficiencies include:
- Vitamin B12 deficiency
- Thiamine deficiency (causing Wernicke-Korsakoff syndrome)
Modifiable Risk Factors
Various lifestyle factors have been shown to significantly reduce the risk of developing dementia:
- Exercise
- Mental stimulation (e.g., a more mentally challenging job)
- Maintaining a healthy weight (obesity increases the risk)
- Blood pressure control (hypertension increases the risk)
- Blood glucose control (diabetes increase the risk)
Presentation
Typically, the symptoms have a slow and insidious onset. It may take months or years before they are recognised as possible dementia. Having a collateral history from a close contact, such as a family member, is helpful.
Early symptoms of dementia include:
- Forgetting events
- Forgetting names
- Difficult remembering words
- Repeatedly asking the same questions
- Impaired decision making
- Reduced flexibility
As the condition progresses, memory and cognitive impairment worsen. Eventually, patients lose the ability to complete self-care tasks such as cooking, cleaning, and dressing themselves.
Features of advanced dementia include:
- Inability to speak or understand speech (aphasia)
- Swallowing difficulties (dysphagia), which can lead to aspiration and pneumonia
- Appetite and weight loss
- Incontinence
Memory Screening Tests
Screening tests involve a shorter list of questions that test memory and cognition. They can be used at the initial presentation as a simple objective measure of cognitive capacity. Options include:
- Six Item Cognitive Impairment Test (6CIT)
- 10-point Cognitive Screener (10-CS)
- Mini-Cog
- General Practitioner Assessment of Cognition (GPCOG)
- Montreal Cognition Assessment (MoCA)
Investigations
Initial blood tests, required to exclude a physical cause before referring to the memory clinic, include:
- Full blood count
- Urea and electrolytes
- Liver function tests
- Inflammatory markers (e.g., CRP and ESR)
- Thyroid profile
- Calcium
- HbA1c
- B12 and folate
Additional tests include:
- Mid-stream urine (MSU) if infection is suspected
- Chest x-ray (if lung cancer is suspected)
Specialist investigations will include imaging (e.g., MRI brain) to exclude structural pathology.
ACE–III
The Addenbrooke’s Cognitive Examination-III (ACE-III) is a detailed and comprehensive assessment tool for memory impairment, typically used by specialist memory services. It can take up to 90 minutes to complete. Five domains are tested:
- Attention
- Memory
- Language
- Visuospatial function
- Verbal fluency
It is scored out of 100 points. Answering perfectly scores 100. A score of 88 or less is typically considered to indicate possible dementia. Lower scores indicate more severe impairment.
Management
Dementia is a progressive condition that is not curable. The mainstay of management involves supporting patients and carers in coping with the symptoms.
Planning ahead during the early stages involves:
- Lasting power of attorney (nominating a person to make decisions on their behalf when they are no longer able)
- Advanced decisions (around treatments they would want or not want)
- Planning future care, including places and end-of-life care
Alzheimer’s disease has drug options to help improve symptoms:
- Acetylcholinesterase inhibitors (e.g., donepezil, rivastigmine or galantamine)
- Memantine, which works by blocking N-methyl-D-aspartic acid (NMDA) receptors
Behavioural and Psychological Symptoms of Dementia
Behavioural and psychological symptoms of dementia (BPSD) include:
- Depression
- Anxiety
- Agitation
- Aggression
- Disinhibition (e.g., sexually inappropriate behaviour)
- Hallucinations
- Delusions
- Sleep disturbance
BPSD can be challenging to manage. Initial steps include:
- Treating underlying causes (e.g., pain, constipation or urinary retention)
- Environmental factors (e.g., providing a calming setting and removing triggers)
- Appropriately trained carers
- Appropriate supervision (one-to-one observation may be required)
- Music therapy
Medication options for managing BPSD are only used where necessary and cause significant side effects. Options include:
- SSRI antidepressants for depressive symptoms
- Antipsychotic drugs (typically risperidone first-line)
- Benzodiazepines (only for crisis management)
Last updated June 2024
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