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Corticobasal degeneration (CBD) is a rare condition that can cause gradually worsening problems with movement, speech, memory and swallowing.
It's often also called corticobasal syndrome (CBS).
CBD is caused by increasing numbers of brain cells becoming damaged or dying over time.
Most cases of CBD develop in adults aged between 50 and 70.
The symptoms of CBD get gradually worse over time. They are very variable and many people only have a few of them.
Symptoms can include:
One limb is usually affected at first, before spreading over several years to affect other parts of the body. The rate at which the symptoms progress varies widely from person to person.
One limb is usually affected at first, before spreading to the rest of the body. The rate at which the symptoms progress varies widely from person to person.
Read more about the symptoms of CBD.
CBD occurs when brain cells in certain parts of the brain are damaged as a result of a build-up of a protein called tau.
The surface of the brain (cortex) is affected, as well as a deep part of the brain called the basal ganglia.
Tau occurs naturally in the brain and is usually broken down before it reaches high levels. In people with CBD, it isn't broken down properly and forms harmful clumps in brain cells.
CBD has been linked to changes in certain genes, but these genetic links are weak and the risk to other family members is very low.
There's no single test for CBD. Instead, the diagnosis is based on the pattern of your symptoms. Your doctor will try to rule out other conditions that can cause similar symptoms, such as Parkinson's disease or a stroke.
You may need to have a brain scan to look for other possible causes of your symptoms, as well as tests of your memory, concentration and ability to understand language.
The diagnosis must be made or confirmed by a consultant with expertise in CBD. This will usually be a neurologist (a specialist in conditions affecting the brain and nerves).
Read more about how CBD is diagnosed.
As someone with CBD can be affected in many different ways, treatment and care is best provided by a team of health and social care professionals working together. Treatments may include:
Read more about how CBD is treated.
There is currently no treatment that has been shown to stop CBD getting gradually worse, although treatments can reduce many of the symptoms.
Good care and assistance can help someone with CBD be more independent and enjoy a better quality of life, but the condition will eventually put them at risk of serious complications.
CBD usually changes very slowly. Many people find it helpful to plan ahead with their doctors (GP and specialist) to make decisions about what to do in later stages of the illness.
Difficulty swallowing can cause choking, or inhaling food or liquid into the airways. This can lead to pneumonia, which can be life-threatening.
As a result of these complications, the average life expectancy for someone with CBD is around six to eight years from when their symptoms start. However, this is only an average and CBD is very variable.
If you have CBD, your clinical team will pass information about you on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).
This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.
People with corticobasal degeneration (CBD) develop a range of difficulties with movement, speech, memory and swallowing.
The symptoms typically become more severe over several years, although the speed at which they worsen varies.
Some of the main symptoms of CBD are outlined below. Most people with the condition won't experience all of these.
CBD typically affects one of the limbs at first. This is usually a hand or arm, but sometimes a leg.
Problems affecting the limb can include:
Some people also develop problems with walking and co-ordination.
As CBD progresses, it may eventually start to cause problems in your other limbs.
Walking, balance and co-ordination may get worse. Many people have problems with their speech, which will become slow and slurred.
Some people with CBD also have dementia, although this doesn't always occur, symptoms may include:
It's also common for someone with CBD to experience personality changes, such as becoming apathetic, irritable, agitated or anxious.
As CBD reaches an advanced stage, muscle stiffness will continue to get worse. People with the condition may lose the ability to move one or more limbs. Some people are unable to walk and need a wheelchair or assistance to transfer (such as help getting into and out of bed).
Other problems people with advanced CBD can experience include:
As a result of swallowing problems, many people with CBD develop chest infections caused by fluid or small food particles falling down into their lungs (aspiration pneumonia), which can be life-threatening.
It can be difficult to diagnose corticobasal degeneration (CBD), as there's no single test for it, and the condition can have similar symptoms to a number of others.
A diagnosis of CBD will be based on the pattern of your symptoms. Your doctor will also try to rule out conditions that can cause similar symptoms, such as Parkinson's disease, a stroke, motor neurone disease and Alzheimer's disease.
Your doctor will need to carry out assessments of your symptoms, as well as other tests and scans.
The diagnosis must be made or confirmed by a consultant with expertise in CBD. This will usually be a neurologist (specialist in conditions affecting the brain and nerves).
If you have symptoms of CBD that suggest there's something wrong with your brain, it's likely you'll be referred for a brain scan.
Types of scan that you may have include:
These scans can be useful in ruling out other possible conditions, such as brain tumours or strokes.
MRI scans can also detect abnormal changes to the brain that are consistent with a diagnosis of CBD, such as shrinkage of certain areas.
Scans that show the build-up of the tau protein in the brain that's associated with CBD are currently under development.
A person's symptoms and signs usually help distinguish CBD from Parkinson's disease, but sometimes tests may be used to support the diagnosis and rule out other possible conditions.
You may be prescribed a short course of a medication called levodopa. This typically works very well in Parkinson's disease, but not so well in CBD.
If it doesn't lead to a significant improvement in your symptoms, it can help your doctor distinguish CBD from Parkinson's disease.
It's also likely you'll be referred to a neurologist and possibly also a psychologist for neuropsychological testing.
This involves having a series of "memory tests" with words and pictures. They're designed to evaluate the full extent of your symptoms and their impact on your mental abilities.
The tests will look at abilities such as:
Most people with CBD have a distinct pattern of difficulties on these tests.
The memory of previously learned facts and the person's own life story is generally maintained.
Being told that you have CBD can be devastating and difficult to take in.
You may feel numb, overwhelmed, angry, distressed, scared or in denial. Some people are relieved that a cause for their symptoms has finally been found. There's no right or wrong way to feel – everybody is different and copes in their own way.
Support from your family and care team can help you come to terms with the diagnosis.
The PSP Association can give you information and practical advice about living with CBD, as well as providing support to help you cope with the emotional impact of the condition.
You can get in touch with the PSP Association by calling their helpline on 0300 0110 122, or by emailing: email@example.com.
You may find that many people – even the doctors you meet – have not heard of CBD. The PSP Association has online and printed information for patients, their families and professionals.
There's currently no cure for corticobasal degeneration (CBD) and no treatment to slow it down, but there are lots of things that can be done to help manage the symptoms.
Care will be provided by a team of health and social care professionals working together. This is known as a multidisciplinary team.
Members of your multidisciplinary team may include:
A care plan will be drawn up in discussion with your team. This will outline the treatments you need to help with the symptoms of CBD, as well as the support and advice you require to make your life easier.
There are currently no medications that treat CBD specifically. Depending on the person's symptoms or complications, the following may be used:
In general, people with CBD are sensitive to medication side effects. Doses may start low and be increased gradually.
Some medications should be avoided completely, such as haloperidol (a medicine used to treat some mental health problems).
Cognitive stimulation is a type of therapy used to treat dementia, and it may be helpful if a person with CBD has dementia symptoms.
It involves taking part in activities and exercises designed to improve your memory, problem-solving skills and language ability.
Read more about how dementia is treated.
A physiotherapist can give advice about how to remain safely mobile. Regular exercise can help strengthen your muscles, improve your posture and prevent stiffening of your joints.
They can teach you breathing exercises to use when you eat, to reduce your risk of developing aspiration pneumonia (a chest infection caused by food particles falling into your lungs).
Read more about physiotherapy.
An occupational therapist can give you advice about the best ways to increase your safety and prevent trips and falls during your day-to-day activities.
For example, a person with CBD may benefit from having bars placed along the sides of their bath to make it easier to get in and out.
The occupational therapist can also arrange access to mobility equipment such as walking frames wheelchairs, and to equipment to help the person or their carer manage other everyday activities for washing, dressing, eating, and using the bathroom safely.
A speech and language therapist can help assess and treat speech and swallowing problems.
They can teach people a number of techniques to help make the voice as clear as possible and can advise you about suitable communication aids or devices that the person may need as CBD progresses.
A therapist can also advise you about different swallowing techniques and, working together with a dietitian (see below), they may suggest altering the consistency of your food to make swallowing easier.
You may be referred to a dietitian, who will advise you about making changes to your diet, such as including food and liquids that are easier to swallow, while ensuring that you have a healthy, balanced diet.
Feeding tubes may be recommended for severe swallowing problems, where the risk of malnutrition, weight loss, fatigue and dehydration is increased. You should discuss the pros and cons of feeding tubes with your family and care team.
The decision about whether and when to consider a feeding tube depends on the individual and should be discussed with a specialist.
Read more about treating swallowing problems.
Palliative care aims to relieve pain and other distressing symptoms while providing psychological, social and spiritual support. It can be offered at any stage of CBD, alongside other treatments.
Palliative care can be received:
Read more about accessing palliative care.
Many people with CBD make plans for the future that outline their wishes about medical care and other decisions. They share these plans with both their family and the health professionals involved in their care.
This can be useful in case you're unable to communicate your decisions later on because you're too ill. However, you don't have to do it if you don't want to.
Issues that you may want to cover include:
If you decide to discuss these issues, they can be written down in a number of ways:
Your care team can provide you with more information and advice about these decisions and how best to record them.
Read more about end of life care.