Symptoms – Corticobasal degeneration
People with corticobasal degeneration (CBD) develop a range of difficulties with movement, speech, memory and swallowing.
The condition tends to develop gradually, which means it can be mistaken for another condition at first – such as Parkinson’s disease, dementia or a stroke.
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:
- a clumsy or “useless” hand
- muscle stiffness
- shaking (tremors) and spasms (dystonia)
- loss of feeling
- feeling like the limb doesn’t belong to you (an “alien” limb)
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:
- problems recalling words, reading and using correct language (aphasia)
- short-term memory loss
- problems carrying out tasks that require planning or thinking ahead
- problems coping with sudden and unexpected situations
- difficulty with numbers and counting
- difficulty seeing things, or knowing where they are located (such as furniture)
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 1 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:
- worsening speech problems, which can make it hard for others to understand you
- uncontrollable blinking
- worsening dementia, meaning constant care may be needed
- increasing difficulties swallowing, which may mean a feeding tube is required
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.
Page last reviewed: 01 August 2019
Next review due: 01 August 2019
Read about the main symptoms of corticobasal degeneration (CBD), and find out how they progress over time.
Overview – Corticobasal degeneration
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:
- difficulty controlling your limb on one side of the body (a “useless” hand)
- muscle stiffness
- shaking (tremors), jerky movements and spasms (dystonia)
- problems with balance and co-ordination
- slow and slurred speech
- symptoms of dementia, such as memory and visual problems
- slow, effortful speech
- difficulty swallowing
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.
What causes 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).
Treatments for CBD
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:
- medication – to improve stiffness and muscle spasms, sleep and mood, pain or memory
- physiotherapy – to help with movement and balance difficulties
- speech and language therapy – to help with communication and swallowing problems
- occupational therapy – to improve the skills and abilities needed for daily activities at home
- palliative care and advanced care planning
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 6 to 8 years from when their symptoms start. However, this is only an average and CBD is very variable.
Information about you
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.
Page last reviewed: 20 August 2018
Next review due: 20 August 2021
Read about corticobasal degeneration (CBD), a rare condition where brain cells become damaged over time and certain sections of the brain start to shrink.