Vascular dementia is the second most common type of dementia in older adults, after Alzheimer’s disease.
It results from injuries to vessels that supply blood to the brain, often after a stroke or series of strokes.
The symptoms of vascular dementia can be similar to those of Alzheimer’s, and both conditions can occur at the same time (a condition called "mixed dementia").
- Also known as vascular cognitive impairment.
- Pure vascular dementia accounts for 12 per cent of cases in the community, while Alzheimer’s and vascular dementia would account for 38 per cent of cases.
- It’s caused by a wide range of blockages and/or bleeding in the brain severe enough to cause damage to brain cells, resulting from strokes, small vessel disease, or Cerebral Amyloid Angiopathy (CAA). This causes the death of brain cells and prevents the brain from functioning as it should.
- If stroke-related, it can be caused by multiple or single events and permanent or temporary blockages.
- Small vessel disease is caused by disease of the very small blood vessels that lie deep in the brain. The blood vessels become thick-walled, stiff and tortuous, reducing blood flow to the deeper part of the brain. This causes small infarcts near the base of the brain and damages the bundles of nerves that carry signals around the brain. Historically this has been referred to as white matter disease.
- Cerebral Amyloid Angiopathy is associated with amyloid deposition in the walls of the arteries in the brain. This leads to microbleeds and haemorrhages in the brain.
What are the symptoms of vascular dementia?
- Early symptoms include periods of confusion, severe depression, emotional changes, mild memory loss, language and visuospatial impairment. As it progresses, the person’s thinking process slows down and the person would have difficulty planning, organizing and executing step-wise tasks.
- The symptoms often appear suddenly, following a major stroke or leakage of blood in the brain; but can also appear gradually through a series of strokes. The symptoms follow a step-wise progression.
- In post-stroke cognitive impairment, physical symptoms may be present, based on the part of the brain affected and the severity of stroke. It may be associated with weakness, paralysis, impaired speech or vision. The symptoms improve or stabilize in six months.
- In small vessel disease, the symptoms are usually of gradual onset, and less variable with time. The usual symptoms are the insidious onset of cognitive slowing, slowing of the thinking process, the early loss of bladder control, mild one-sided weakness, difficulty walking, clumsiness, lack of facial expression, difficulty with word pronunciation etc.
- Vascular dementia is considered the most preventable type of dementia because it is so closely related to cardiovascular health.
What are the risk factors for vascular dementia?
- Risk factors for vascular dementia are the same as those of cardiovascular disease - smoking, high blood pressure, diabetes, high cholesterol, physical inactivity, high-carb high-fat diet and ethnic origin (Indian, Pakistani, Bangladeshi, Sri Lankan, and African-Caribbean).
- Risks of developing vascular dementia can be reduced by keeping blood pressure, blood sugar, cholesterol and body weight in the recommended range and following healthy lifestyle choices including regular exercise, avoidance of smoking and limiting alcohol intake.
Several genetic disorders are associated with the development of vascular cognitive impairment.
- Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a rare, inherited disorder that affects the small blood vessels in the brain and leads to vascular dementia or vascular cognitive impairment and other symptoms. This condition is associated with cognitive impairment, migraine headaches and risk of stroke. It is caused by an inherited genetic mutation (in the NOTCH3 gene) affecting small blood vessels.
- Another hereditary vascular syndrome is CARASIL that stands for Cerebral Autosomal Recessive Arteriopathy with Subcortical Infarcts and Leukoencephalopathy, occurs due to mutations in the HTRA1 gene. It is associated with alopecia, and spondylosis, in addition to cerebral small vessel disease.
Familial cerebral amyloid angiopathy has been described with mutations in the APP, ITM2B, and CST3 genes.
How is vascular dementia diagnosed?
- Diagnosis of vascular dementia is made based on a person’s symptoms, medical history, current health and lifestyle, blood tests, imaging tests and cognitive assessment. Following the initial blood tests to rule out treatable causes, the doctor would refer the person to a specialist for cognitive tests to assess their attention, planning and thinking speed. The specialist may carry out brain scans to help make a diagnosis. CT scan and MRI scan may show changes associated with stroke or white matter disease, in addition to revealing fluid buildup or tumours in the brain, if present.
- Investigations will also aim to identify conditions that may be contributing to the progression of vascular dementia. These conditions include high blood pressure, heart problems, diabetes and high cholesterol.
- If the person has any family history of vascular dementia, or related conditions (such as heart problems), they should mention this to the doctor.
- Always consult a doctor if you experience any sudden symptoms, such as slurred speech, weakness on one side of the body, or blurred vision - even if they are only temporary. These symptoms may be caused by temporary interruptions in the blood supply within the brain. If left untreated, they can lead to permanent damage.
Is there a cure? Can vascular dementia be treated?
- Unfortunately, there is currently no cure for vascular dementia or for reversing the changes in the brain caused by vascular dementia. Management includes identifying the underlying cause and treating it to prevent further strokes. This may help slow down the progression of vascular dementia.
Treatment includes medications for maintaining blood pressure, cholesterol and blood sugar in the normal range. Treatment also focuses on preventing clots, incorporating lifestyle strategies such as regular exercise, adopting the Mediterranean diet, avoiding smoking, minimizing alcohol, and engaging in physiotherapy and rehabilitation to regain strength.
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