Overview of Corticobasal Degeneration

Corticobasal degeneration (CBD), also known as corticobasal ganglionic degeneration, is a rare, progressive neurological disorder. In CBD, brain cells atrophy (shrink) and die, and tau protein deposits build up in the brain and interfere with functioning. CBD is considered to be a type of frontotemporal dementia.

CBD shares several symptoms with Parkinson’s disease. Early symptoms include slow or clumsy movements, tremors or shakiness, muscle weakness, and stiffness. Often, the person with CBD initially has symptoms only on one side of the body. Later, as the disease progresses, both sides are affected.

Some people with CBD experience what is commonly called an "alien limb." This term refers to an arm or leg that seems to move without any direction of the person. It may not even feel like the arm or leg is a part of the person's body.

CBD also affects the ability to speak and understand what others are saying and can affect memory and the ability to do mathematical calculations. Finding the right word may become very difficult. Changes in personality may develop and can include compulsions, socially inappropriate behaviors, and repetitive actions.

Researchers have not yet determined what causes CBD, although it does not appear to be an inherited disorder. The average age of onset is around 60. There are an estimated 2,000 to 3,000 Americans with this disorder, although it's possible that there are others who have an inaccurate diagnosis since CBD is often initially misdiagnosed as Parkinson's or Alzheimer's disease.

As with the other disorders in the frontotemporal dementia group, the treatment of CBD is limited. Medications that may help relieve some of the symptoms for a limited time include cognitive enhancers (drugs used to attempt to improve the ability to think and remember) that are usually prescribed in Alzheimer’s disease, such as cholinesterase inhibitors.

Other people show some improvement in their physical abilities with medications like Sinemet, a drug often used in Parkinson's, Baclofen (which helps reduce muscle rigidity or tightness), or Clonazepam, which may help decrease the muscle jerks.

Physical, occupational, and speech therapy may also be ordered by the physician to try to improve the motor functioning and speech, as well as prevent muscle contractures.

CBD is a progressive disease that often causes immobility after about five years; within 10 years, the person may pass away from complications such as a pulmonary embolism, pneumonia, or another infection.