Multi-infarct dementia (MID) is a type of vascular dementia. It occurs when a series of small strokes causes a loss of brain function. A stroke, or brain infarct, occurs when the blood flow to any part of the brain is interrupted or blocked. Blood carries oxygen to the brain, and without oxygen, brain tissue quickly dies.
The location of the stroke damage determines the type of symptoms that occur. MID can cause a loss of memory and cognitive function and can initiate psychological problems. Treatment focuses on controlling the symptoms and reducing the risk for future strokes.
The symptoms of MID may appear gradually over time, or they may occur suddenly after a stroke. Some people will appear to improve and then decline again after they have more small strokes.
The early symptoms of dementia include:
- getting lost in familiar places
- having difficulty performing routine tasks, such as paying the bills
- having difficulty remembering words
- misplacing things
- losing interest in things you used to enjoy
- experiencing personality changes
More obvious symptoms appear as dementia progresses. These can include:
- changes in sleep patterns
- difficulty with basic tasks, such as dressing and preparing meals
- poor judgment
- social withdrawal
- memory loss
MID is caused by a series of small strokes. A stroke, or infarct, is the interruption or blockage of blood flow to any part of the brain. The term “multi-infarct” means many strokes and many areas of damage. If blood flow is stopped for more than a few seconds, brain cells can die from a lack of oxygen. This damage is usually permanent.
A stroke can be silent, which means it affects such a small area of the brain that it goes unnoticed. Over time, many silent strokes can lead to MID. Large strokes that cause noticeable physical and neurological symptoms can also lead to MID.
MID generally occurs in people aged 55 to 75 years and is more common in men than in women.
Medical conditions that increase the risk of MID include:
- atrial fibrillation, which is an irregular, rapid heartbeat that creates stagnation that can lead to blood clots
- previous strokes
- heart failure
- cognitive decline prior to a stroke
- high blood pressure
- atherosclerosis, or hardening of the arteries
Lifestyle Risk Factors
The following are lifestyle risk factors for MID:
- a low level of education
- a poor diet
- little to no physical activity
There’s not a specific test that can determine MID. Each case of MID is different. Memory can be seriously impaired in one person and only mildly impaired in another person.
Diagnosis is often made based on:
- a neurological exam
- a history of stepwise mental decline
- CT or MRI scans that detail small areas of tissue that died from a lack of blood supply
- ruling out other organic causes of dementia such as high cholesterol, diabetes, high blood pressure, or carotid stenosis
Radiological imaging tests can include:
- CT scans of your brain
- MRI scans of your brain
- an electroencephalogram, which is a measure of the electrical activity of the brain
- a transcranial doppler, which allows your doctor to measure the velocity of blood flow through your brain’s blood vessels
Ruling Out Other Causes of Dementia
Your doctor may also order tests to rule out other conditions that may cause or contribute to dementia, such as
- a brain tumor
- a chronic infection
- thyroid disease
- a vitamin deficiency
- drug intoxication
Treatment will be tailored to your individual needs. Most treatment plans include medication and lifestyle changes.
Medications may include:
- folic acid
- selective serotonin reuptake inhibitors, which are antidepressants that may also help neurons grow and reestablish connections in the brain
- calcium channel blockers for short-term cognitive function
- angiotensin-converting enzyme inhibitors to lower blood pressure
Herbal supplements have grown in popularity as treatments for MID. However, not enough studies have been done to prove that their use is successful. Examples of herbal supplements that are currently being studied for use in treating MID include:
- Artemisia absinthium, or wormwood, which is used to improve cognitive function
- Melissa officinalis, or lemon balm, which is used to restore memory
- Bacopa monnieri, or water hyssop, which is used to improve memory and intellectual function
Be sure to discuss these supplements with your doctor before taking them, as they can interfere with other medications.
Other options for treatment include regular exercise to build muscle strength, cognitive training to regain mental function, and rehabilitation for mobility issues.
MID has no cure. Medications and cognitive training may help preserve mental function. The speed and advance of dementia varies. Some people die soon after an MID diagnosis, and others survive for years.
There’s no evidence of any effective measure to avoid MID. As with many conditions, the best prevention method is to take care of your body. You should:
- Visit the doctor regularly.
- Eat a balanced diet.
- Begin or maintain a regular exercise program.
- Ensure good blood pressure control.
- Maintain diabetic control.