Corticobasal degeneration (CBD) is a progressive condition. This means that the symptoms develop gradually, before becoming more severe over many years.
However, it is important to realise that only a few people will experience all the symptoms outlined below. Also, individual symptoms can vary in severity from person to person.
The most common initial symptom of CBD is a sudden difficulty controlling one of your limbs. In most people, this is usually their hand or arm, but sometimes a person's leg can be affected.
You may have muscle stiffness, rigidity and spasms in your limb, and you will probably find it increasingly difficult to use the affected limb. Some people with CBD have reported that it feels like the affected limb is no longer under their control, and does not belong to them. This is known as alien limb syndrome.
Another common initial symptom of CBD is that you begin to lose your sense of balance and co-ordination, which leads to walking difficulties.
As CBD progresses, it will affect other limbs, usually in both your arms and legs.
Balance and co-ordination will get worse and many people find it increasingly difficult to walk. Most people will have problems with their speech, which will become slow and slurred, making it difficult to understand.
Eye muscles are usually also affected. Many people have problems moving their eyes up and down and, less commonly, to the left and right. This can increase the risks of falls and cause problems carrying out everyday tasks, such as eating and reading.
At this stage, many people with CBD start to have symptoms of dementia, including:
- problems recalling words and expressing yourself using the correct language
- short-term memory loss and increasing forgetfulness
- problems doing tasks that require planning
- problems coping with sudden and unexpected situations, such as suddenly realising that you have forgotten the keys to your house
It is also common for someone with CBD to experience personality changes and become depressed, apathetic, irritable, agitated or anxious.
A small number of people with CBD also develop obsessive compulsive disorder (OCD).
As CBD reaches an advanced stage, the symptoms of muscle stiffness and rigidity will continue to get worse, and you may lose the ability to move one or more of your limbs. Some people with advanced CBD are unable to walk and need a wheelchair.
The quality of your speech will probably continue to deteriorate and people may have difficulty understanding you.
Problems controlling your eye muscles are also likely to get worse. Some people with advanced CBD will not be able to change the direction of their gaze and will only be able to stare straight ahead.
For a small number of people with advanced CBD, dementia will worsen and they will require constant care.
Most people with advanced CBD will find it increasingly difficult to swallow food and liquid. This is known as dysphagia. At some point, people with CBD will need to consider the possible benefits and drawbacks of using a feeding tube.
As a result of dysphagia, many people with CBD will experience repeated chest infections caused by fluids or small particles of food that inadvertently fall down into their lungs. This can lead to a serious condition called aspiration pneumonia, which is the leading cause of death in cases of CBD.
Read more about aspiration pneumonia.