A-Z of health
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CBD
Introduction
[Original article on NHS Choices website]
Corticobasal degeneration (CBD) is a rare condition where brain cells become damaged over time and certain sections of the brain start to shrink.
CBD is a progressive condition. This means that the initial symptoms will become more severe over time, and new symptoms may also develop.
Initial symptoms of CBD include:
- sudden difficulties in controlling certain limbs
- loss of balance and co-ordination (the medical term for this is ataxia)
As the condition progresses, symptoms become more wide ranging and troublesome, such as:
- muscle spasms and stiffness
- ongoing decline of mental functions (dementia)
- difficulties swallowing food and liquid (dysphagia)
- difficulties speaking
Read more about the symptoms of corticobasal degeneration.
What causes CBD?
In CBD, brain damage occurs because a protein called tau, which is normally found in low levels in the brain, builds up and forms clumps which kill nearby brain cells.
This damages vital parts of the brain (such as the cortex and the basal ganglia) that are responsible for important functions including:
- movement
- speech
- higher thought processes such as planning and understanding
It is not known exactly why there is an excess of tau protein that forms clumps.
Read more about the causes of corticobasal degeneration.
Treating CBD
There is no cure for CBD. Several medications, such as memantine, have been suggested to slow the progression of CBD symptoms and improve the function of the brain, but it is still unclear how effective they are.
Most treatments for CBD focus on relieving symptoms and helping people cope better with daily life. These include medication to relax muscles and using feeding tubes to overcome difficulties swallowing.
Read more about treating corticobasal degeneration.
Who is affected?
CBD is a rare condition.
It is difficult to know exactly how many people are affected as it is often misdiagnosed as another condition, such as a stroke or progressive supranuclear palsy, which share similar symptoms.
It was recently estimated that 1 person in 20,000 is living with CBD.
CBD mostly affects people who are 60 to 80 years old. It may be more common in women than in men, but because the condition is so rare, it is difficult to be certain.
The number of reported cases of CBD has risen sharply in the last twenty years. It is unclear whether this is due to CBD becoming more widespread or because doctors are better at diagnosing the condition.
Outlook
Although CBD itself isn’t life-threatening, it can lead to serious complications. One of the most common complications is difficulty swallowing (dysphagia), which can cause a person to choke or inhale food or liquid into the airway (aspiration). Aspiriation can develop into pneumonia, which can be fatal.
Read more about the complications of CBD.
Most people with CBD will not live longer than ten years after symptoms start.