Computer on the fritz- The Human Brain and Dementia

The human brain, a complex super computer, built up of billions of neurons all communicating to form a network to control every action of the body. But what happens when things go wrong, when this network is interrupted? Dementia is an umbrella term for many diseases of the brain and affects many aspects of normal functioning. Alzheimer’s disease is the most common of these, accounting for 50-60% of dementia cases. When talking about dementia many of us think of Alzheimer’s Disease, and the two terms are almost used interchangeably. However there are other forms of dementia, one of which being vascular dementia which affects more than 111000 people in the UK. More interestingly however, is that vascular dementia is a form of dementia which can be prevented.

What Causes Vascular Dementia?

Every cell in our body requires nutrients such as oxygen to survive; these nutrients are supplied via the bloodstream. The brain requires the same nutrients, thus if blood flow is interrupted, via restriction or obstruction, brain cells (neurons) starve and die. Damage to the brain can result from a major interruption to blood flow (stroke) or gradually from minor interruptions .  These minor interruptions occur from blockages of small blood vessels within the brain, known as small vessel disease, and  is the most common cause of vascular dementia. The amount of damage corresponds to the severity of the symptoms and in the same way as damage occurs symptoms can also be sudden or gradual.

What are the symptoms of Vascular Dementia?

The Brain is split into sections, each with a particular function. Therefore symptoms depend on the sites of the brain which are affected. Cognitive symptoms may include; confusion, disorientation, trouble speaking or understanding speech and vision loss. These may be accompanied with physical symptoms, including; walking difficulty and  numbness/ paralysis to one side of the body. With gradually worsening vascular dementia there are early common symptoms, collectively known as vascular cognitive impairment, such as; planning, judgment, attention and memory impairment.  At this early stage further brain cell death can be stopped.

Functions of areas of the human brain

Sections of the human brain and their functions

What treatment is available?

The most effective treatment is prevention, and by this I mean preventing the problem becoming worse via further narrowing or blockage of blood vessels. Therefore the individual should not smoke, aim to reduce blood pressure, cholesterol and blood sugar (there are drugs which do this), exercise and maintain a healthy diet and body weight.

Once vascular dementia is established, whether this is due to a stroke or small vessel disease, progression of the disease unfortunately cannot be stopped, just slowed.  Alzheimer’s treatments may be used. However they are less effective at treating vascular dementia than Alzheimer’s disease. There are two Alzheimer’s drugs available;

i)                    Acetylcholinesterase inhibitors such as donepezil, which act to increase the amount of the neurotransmitter acetylcholine, important in the communication of neurons.

ii)                   Memantine which acts to block NMDA glutamate receptors. It therefore acts to reduce the effect of glutamate, a neurotransmitter which at high levels kills neurons.

Cerebrolysin is a new drug, and although it is not currently licensed for use in the UK, its ability to improve thinking and memory in this disease is very promising . Hopefully this will be the future of vascular dementia treatment.  Finally there are numerous rehabilitative therapies which show benefits in regaining some lost functions.

The Greater Picture

Life expectancy is increasing and shows no sign of slowing down.  Great we all get to live longer, but what is the price of those extra years?  Age related diseases including dementia are on the increase. This will have a huge economic impact. Just think of the strain on the NHS due to the increasing number of patients, but more importantly think of the impact dementia has on the family of the unfortunate individual. It is not all doom and gloom however there is hope on the horizon with the  increased knowledge of all types of dementia and a lot of research underway to try and  treat or cure these diseases.

The future is bright…



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