Corticobasal degeneration

Corticobasal Degeneration (CBD) is a rare and progressive neurodegenerative disorder.

Corticobasal Degeneration (CBD) is a rare and progressive neurodegenerative disorder.

CBD affects movement, speech, thinking processes (cognition) and behaviour.

Although there’s currently no cure for CBD, a range of drugs, treatments and therapies are available to manage the symptoms.

CBD symptoms usually develop between the ages of 60 to 70.

There is nerve cell loss and shrinkage in multiple areas of the brain.

There is a wide range of symptoms that vary greatly between people. CBD is closely linked to Progressive Supranuclear Palsy (PSP) because of a similar underlying pathology.

Diagnosis of corticobasal degeneration

The diagnosis of CBD can be difficult to make. There are currently no diagnostic tests available to confirm CBD.

A neurologist specialising in movement disorders is the recommended medical person to see when seeking a diagnosis.

The diagnosis of CBD can be delayed due to the wide range of symptoms and because the early symptoms are similar to those in Parkinson’s disease and PSP.

People with CBD either present with motor symptoms or with a frontotemporal dementia syndrome.

It may take several assessments and observations by the neurologist before they are confident of the diagnosis of CBD.

Causes of corticobasal degeneration

The deterioration in brain cells in several areas of the brain, including the cortex and the basal ganglia leads to the symptoms found in CBD.

In CBD there is an abnormal build-up of the protein called tau in the brain. The abnormal tau is thought to damage nerve and brain cells in certain regions of the brain.  It is not known what triggers this build-up of tau.

It remains uncertain if there is a genetic link to CBD. Changes to the tau gene are associated with CBD.

No environmental or infective factors have been linked to CBD to date.

Symptoms of corticobasal degeneration

The symptoms can vary between people as differing parts of the brain can be affected.  Not everyone will develop all of the symptoms.

The main symptoms include:

  • changes to movement such as clumsiness in a hand, difficulty performing normal movements, dystonia and rigidity or stiffness
  • speech and swallowing difficulties
  • thinking or cognitive problems
  • behavioural changes

Movement control is affected on one side of the body initially but eventually all of the body is affected.

Movement can be slow and stiff similar to PD and there can be difficulty performing voluntary movements with the limbs on one side (apraxia).

Dystonia (abnormal muscle activity and postures) is often present in one hand and may eventually result in contractures

The movement changes include

  • difficulty controlling the limbs on 1 side of the body – called ‘alien limb syndrome’
  • difficulty performing normal movements of the affected arm and leg – called apraxia
  • loss of sense of touch on one side
  • stiffness or rigidity
  • slow movement
  • balance and co-ordination problems which can lead to falls
  • dystonia affecting the arm (hand is fisted)
  • myoclonus or muscular jerks
  • difficulty moving the eyes to look up

Speech problems vary between people and are progressive leading to language loss.

Typical problems include difficulty naming objects, difficulty forming words, difficulty understanding conversations, speech being slow and slurred.

Swallowing difficulties may become progressively more difficult causing choking or aspiration.

Changes to thinking may include memory problems, difficulty following and making sense of conversations, problems planning tasks. Dementia may occur early in some people with CBD.

Behavioural changes may include a change in personality, disinterest in what is happening around them and irritability.

Treatment for corticobasal degeneration

Currently there is no treatment available to stop or slow CBD from progressing.

There are, however, a variety of medical treatments and therapies available to manage the symptoms.

A multidisciplinary team that includes a neurologist and therapists who specialise in movement disorders is recommended for the management of the complex CBD symptoms. The appropriate multidisciplinary team members should be seen from the time the diagnosis of CBD is received.

Medical treatment

A neurologist specialised in movement disorders can advise on medical treatments to treat the presenting symptoms.

The symptoms of slow movement and rigidity may improve in the early stages with PD medications, especially levodopa preparations such as sinemet or madopar.

Myoclonus may be helped with tranquilizers.

Depression can be managed effectively with a range of antidepressants.

There are currently no medications that can reverse or slow down the cognitive changes that occur with CBD.

Apraxia or the inability to perform purposeful movements is the key symptom of CBD. There is no treatment to reverse this phenomenon.

Education of symptoms and managing medications

A nurse with specialist training in CDB can provide education and support to the person with CBD and their caregiver. This may include:

  • monitoring the effects of changes to medications as recommended by the neurologist and liaising with the neurologist
  • providing education and support around the recommended medications and the assist with the minimisation of side effects
  • providing individualised education for the person with CBD and their caregivers to ensure optimal understanding and management of the various CBD symptoms as the condition progresses
  • arranging referrals to other relevant health professionals within the specialist team

Treatments for walking difficulties, balance, falls and posture problems

A physiotherapist specialised in movement disorders such as CBD can assess walking and balance problems and recommend ways to improve mobility and safety.

An occupational therapist specialised in movement disorders such as CBD can assess the person at home and suggest ways to improve safety, both inside and outside the home.

As CBD progresses the physiotherapist and occupational therapist can advise on appropriate seating to help achieve a good posture that is comfortable and makes eating and drinking easier.

A physiotherapist can advise on ways to help the person walk safely, reduce risk of falls and remain independent as long as possible.  This may include the use of equipment, walking frames, protective garments such as hip protectors to reduce risk of hip fractures and the use of a wheelchair.

A physiotherapist can also develop an exercise program to improve or maintain flexibility, strength and fitness.

An occupational therapist may come to the home to advise on ways to improve mobility and safety in the home and the community. An occupational therapist can advise on what equipment best suits the need of the person, such as grab rails next to steps, safety equipment for the shower and toilet. If home modifications are required, they can help with the planning of them.

If posture is affected and is interfering with communication, eating, drinking and comfort, the physiotherapist can prescribe exercises to stretch the tight muscles and joints and the occupational therapist can advise on equipment, such as seating.

The physiotherapist and occupational therapist can also assess the possible causes of any pain, such as poor posture, pain secondary to falls and pressure areas due to staying in one position too long.

An occupational therapist can assess and advise on pressure relieving equipment, such as specialised seating cushions and mattresses.

There are various funding bodies that can fully or partially cover the cost of some home modifications and adaptive equipment such the State Wide Equipment Program (SWEP). An occupational therapist can advise you on how to apply for funds to assist with the costs if required.

The person’s neurologist may suggest injections of botulinum toxin into the cramping or dystonic muscles.

Treatments for speech and swallowing difficulties

A speech pathologist specialised in movement disorders such as CBD can assess the person’s speech and teach strategies to improve them.

Changes to voice will vary between people and as the CBD progresses.

Swallowing difficulties are common in CBD.  Swallowing problems can lead to embarrassment when eating with others socially, loss of enjoyment of food, weight loss, poor nutrition and food or drinks entering the lungs (aspiration). A speech pathologist can assist with any of these swallowing problems.

It is important to see a speech pathologist if any of the following swallowing problems develop as they increase the risk of aspirating fluids or solids into the lung which may then lead to pneumonia.:

  • if there is a need to clear the throat when eating solid foods
  • difficulty swallowing tablets which may feel ‘stuck’ in the back of the throat
  • coughing especially after drinking thin fluids such a tea and coffee
  • choking on solid foods such as meat, toast
  • a wet or gurgly voice after having a drink

If there is a need to go on to a specialised thickened diet to avoid aspiration, the speech pathologist and dietitian will work together to advise on the food groups to select and the best way to prepare them.

Management of nutrition

Due to swallowing difficulties and mood changes the person with CBD may not be eating well and therefore not getting enough nutrients. Adequate intake of nutritional food is essential with CBD.

A dietitian specialised in movement disorders such as CBD can assess the person’s diet and provide them with suggested menus to improve any dietary problems they may have.

A dietitian specialised in movement disorders such as CBD can assess the person’s diet and provide them with suggested menus to improve any dietary problems they may have. The dietitian can ensure the person with CBD is fully informed on what foods they need to eat in order to maintain a nutritional diet, how diet can improve constipation and how to avoid weight loss.

The dietitian will work closely with the speech pathologist to ensure the person with CBD and their caregiver and family know how to lessen the risk of aspiration when eating and drinking.

Managing the social and emotional impact

The effects of CBD are broad and impact on the social and economic life of the person and their family from the time of diagnosis in a variety of ways.

Coping and adjusting to the diagnosis, facing increasing challenges at work and planning for the future can be a daunting undertaking.

Navigating this newfound uncertainty requires careful consideration and appropriate specialised support.

As the disorder progresses, caregiver burden also increases and quality of life can decrease.

A social worker specialised in movement disorders such as CBD can assist the person with CBD, their caregiver and family negotiate the challenges faced across the life time of the person’s condition.

Social workers are highly skilled professionals who can assist you and your loved ones by:

  • providing a range of different therapy’s like counselling
  • assistance with linking to other support services
  • directing you to financial support services
  • information provision of entitlements for care packages
  • help to facilitate suitable respite arrangements for the caregiver
  • assistance and support with navigating the pathway to permanent residential care if the need arises.

After receiving a diagnosis of CBD it is normal to experience a change in mood. A social worker has the appropriate specialised skills to help you deal with the reaction to your diagnosis.

Depression and anxiety are common clinical symptoms of CBD. Depression and anxiety can benefit from a variety of interventions and approaches. It is important to talk openly with your doctor or neurologist if experiencing any of these to determine the best treatment plan for you.

Social workers are specifically trained to support you in understanding how best to manage such symptoms.

Cognition and behaviour

CBD causes changes to the person’s cognition. Cognition refers to mental processes and includes the ability to learn, to reason and remember.

Changes to cognition may make the person feel less confident and anxious.

Behaviour changes and mood changes occur frequently in CBD.

It is important that the person with CBD, their caregiver and family speak to the neurologist about any changes in cognition, behaviour or mood.

A neuropsychologist specialised in movement disorders such as CBD can assess a person’s cognition and provide strategies to optimise independence.

Forgetfulness is a presenting symptom of CBD.

Difficulty in handwriting and tasks such as drawing and copying are frequent in CBD.

As CBD progresses, dementia may develop.

Behavioural changes due to CBD include the loss of motivation, personality changes, disinhibition, inattention and irritability. CBD may result in apathy where the person loses enthusiasm or motivation with their hobbies and they may not want to socialise with family and friends. Depression and anxiety are also found with CBD

There are specialists, such as a neuropsychologists, who can assess the severity of these changes. The information gained from the assessment is important in ensuring the person receives the best care and advice to help them manage these changes.

Though there is no evidence to support the benefits of any medication to improve cognition or prevent its deterioration, a neuropsychologist and occupational therapist can advise on ways to manage the challenges caused by changes to the person’s cognition and behaviour.

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