Vascular dementia known as vascular cognitive impairment (VCI) and multi-infarct dementia is caused by a deterioration of blood vessels. This type of dementia is a loss of brain functioning due to poor blood flow to the brain caused by a series of strokes. The brain has many different regions which are responsible for numerous functions. The cerebrum is divided into two hemispheres which in turn are divided into four lobes responsible for the core functions of the brain. The frontal lobe is responsible for personality, movement, speech, and decision making. The parietal lobe is responsible for processing physical location and sensory information. The temporal lobe is responsible for hearing, smell, memory, and recognition of space. Finally, the occipital lobe’s primary role is to process visual stimulus. Neurons which are cells in the brain can only function in aerobic conditions (constant supply of oxygen) and with a steady amount of glucose. Neurons don’t have long term energy storage so they need a constant supply of blood in order to receive oxygen and glucose. With every heartbeat, a quarter of the blood that pumps out travels directly to the brain via the internal carotid arteries and vertebral arteries located in the neck. Once these arteries reach the base of the neck, they form a ring known as the circle of willis which branches off into small arteries known as perforating arteries that supply the brain with oxygen and glucose.
Vascular dementia occurs in individuals when they develop atherosclerosis in their arteries.
Atherosclerosis is the hardening of the arteries due to a buildup of plaque and is the cause of most strokes involving the carotid artery. High blood pressure as well as diabetes are a contributing factor in the development of atherosclerosis. In some cases, perforating arteries can get affected by atherosclerosis and completely block off blood supply to the brain. In general, when the blood supply to the brain falls below the demand, it causes an ischemic stroke. Ischemic strokes lead to tissue damage in the brain and is usually permanent. This dead tissue undergoes a process called liquefactive necrosis which liquifies the dead tissue. Brain tissue necrosis leads to a loss of cognitive abilities in the region of the brain where it is occurring. If multiple strokes occur in the same area of the brain, it will lead to vascular dementia as it will severely impair daily functioning.
The symptoms of vascular dementia vary based on the region of the brain that is affected by the stroke (infarction). Here are a list of symptoms based on regions of the brain:
Parietal lobe: Aphasia(loss of speech)
Temporal lobe: Memory difficulties
Frontal Lobe: Personality changes
Occipital lobe: trouble with eyesight
Reaction time slowed down
Processing speed of information decreased
Problems with short term memory
Getting lost in familiar surroundings
Trouble with concentration
The general symptoms of vascular dementia are fairly similar to symptoms of Alzheimer’s. In comparison, Alzheimer’s occurs at a slower pace as compared to vascular dementia and occurs because of a build up of beta amyloid plaque and neurofibrillary tangles. The signs of impaired coordination can also help distinguish between the two neurodegenerative disorders. In Alzheimer’s problems with balance and coordination occur during the later stages while in vascular dementia these symptoms are seen early on. In most cases, vascular dementia and Alzheimer’s disorder occur together, this is known as mixed dementia.
Currently, there is no treatment for vascular dementia however treatment focuses on reducing the risk of repeated strokes. Patients should stop smoking and drinking alcohol. Individuals should maintain a balanced diet and exercise for thirty minutes a day at least three days a week. Talk to your loved one’s doctor before starting any medication or implementing new lifestyle changes.