Corticobasal degeneration (CBD) is a progressive condition, which means that the symptoms develop gradually, before becoming more severe over the space of many years.
However, it is important to realise that only a few people will experience all of the symptoms that are outlined below. Also, individual symptoms can vary in severity from person to person.
The most common initial symptom of CBD is a sudden difficulty in 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 experience 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, the problems that you have controlling your limb, and the symptoms of muscle spasms and stiffness, will spread to other limbs, usually in both your arms and legs.
Balance and co-ordination problems will become more pronounced, and many people find it increasingly difficult to walk. Most people will begin to experience problems with their speech, as it becomes slow and slurred, making it difficult to understand.
At this stage, the muscles of the eyes are usually also affected, with many people having problems moving their eyes up and down and, less commonly, to the left and right. This can increase the risks of falls, as well as contributing to problems with eating and carrying out everyday tasks.
At the intermediate stage of the condition, many people with CBD will begin to experience symptoms of mild to moderate dementia. This can take the form of:
- problems recalling words and expressing yourself by using the correct language
- short-term memory loss and increasing forgetfulness
- problems performing tasks that require forward 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 related mental health conditions including:
A significant minority of people with CBD also develop obsessive compulsive disorder (OCD).
This usually takes the form of repetitive actions, such as repeatedly picking up and then putting down an object, an obsessive desire for cleanliness, and repeated 'checking activities', such as checking all the windows are locked or the cooker has been turned off.
During the advanced stages of CBD, 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 require a wheelchair.
The quality of your speech will probably continue to deteriorate and it may become almost unintelligible to others.
Problems controlling your eye muscles are also likely to get worse, and some people with advanced CBD will be unable 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, their 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 time, 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 that are 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.