Week 9: Alzheimer's and Vascular Dementia

Alzheimer's Disease

• Abnormalities in brain structure disrupt neuron health, leading to memory failure, personality changes, and inability to manage daily activities.
• Average life span after diagnosis is 8-10 years.
• Risk factors include age, family history, Down's syndrome, head trauma, female gender, late-onset depression, and mild cognitive impairment.
• 3 consistent neuro-pathological markers: accumulation of beta-amyloid senile plaques, neurofibrillary tangles, and neuronal degeneration.
• Brain-derived tau has potential as a diagnostic biomarker for Alzheimer's.

Disease Progression

• Early to moderate stages: memory lapses, agitation, and speech problems.
• Late stage: visual disturbances, incontinence, motor disability, and speech loss.

Vascular Dementia (VaD)

• Occurs when blood supply to the brain is interrupted by a blocked or diseased vascular system.
• Second most common form of dementia.
• Describes a number of syndromes with different pathology and mechanisms.

Types of VaD

• Mild vascular cognitive impairment
• Multi-infarct dementia
• Vascular dementia due to strategic single infarct
• Vascular dementia due to lacunar lesions
• Vascular dementia due to haemorrhagic lesions
• Sub-cortical (Binswanger disease) dementia
• Mixed dementia (combination of AD and VaD)

Risk Factors for VaD

• Age
• High blood pressure
• Smoking
• Diabetes
• High cholesterol
• Lack of physical activity
• History of mild warning strokes
• Evidence of disease in arteries elsewhere
• Heart rhythm abnormalities
• VaD is slightly more common in men than women.

Signs and Symptoms of VaD

• Physical signs: memory problems, forgetfulness, dizziness, leg or arm weakness, lack of concentration, moving with rapid, shuffling steps, loss of bladder or bowel control.
• Behavioural signs: depression, slurred speech, language problems, abnormal behaviour, wandering/getting lost, laughing/crying inappropriately, difficulty following instructions, problems handling money.

Progression of VaD

• VaD may progress in a 'stepped' manner, with symptoms worsening suddenly due to stroke and then remaining the same for some time.
• Lifespan for people with VaD is approximately 5 years, with death often caused by a stroke or heart attack.
• Early to middle stages: symptoms similar to those observed in other dementia forms, with confusion being one of the earliest symptoms.