FACTSHEET 9: What is corticobasal syndrome?

Frontotemporal dementia or FTD is a progressive disorder of the brain. It can affect behaviour, language skills and movement.

FTD commonly overlaps with parkinsonian disorders causing problems with movement. One of these is called corticobasal syndrome or CBS. It is also sometimes known as corticobasal degeneration or CBD.

In CBS the first symptoms are often those that affect movement. However in some cases these can be preceded by behavioural or language symptoms, and some people may initially carry a diagnosis of behavioural variant FTD or PNFA.

Symptoms affecting movement usually start on one side of the body but may go on to affect both sides. They include the following symptoms that may affect the arm, leg or both:

  • Clumsiness
  • Slowness of movements
  • Stiffness
  • Tremor
  • Jerkiness – this is called myoclonus
  • Holding the arm in an odd posture – this is called an ‘alien limb’
  • Inability to do complex actions with the hands – this is called a limb apraxia.

Does CBS run in families?

In some cases CBS can be a genetic disorder and run in families. Mutations in either the progranulin or tau gene can cause CBS.

See FACTSHEET 2 for more details about familial FTD.

How is CBS diagnosed?

Usually a diagnosis is made by a specialist rather than a GP. See FACTSHEET 11 for more details.

A diagnosis of CBS may be made from the symptoms and signs found on clinical examination. However some tests may also be performed including a brain scan.

Is there a treatment for CBS?

There is currently no cure for CBS but there are some important things which can help when caring for someone – see FACTSHEET 12 for more details.

Drugs used in Parkinson’s disease such as levodopa or other drugs that increase dopamine levels tend to have only a small or no effect on the movement symptoms.

The PSP Association has more information on CBS at www.pspassociation.org.uk.