Corticobasal Degeneration

What is corticobasal degeneration?

Corticobasal degeneration is a neurological (brain) disorder. It damages cells in your brain, causing parts of it to shrink (atrophy). The disease’s symptoms may first appear on one side of your body, but eventually affect both sides as the disease progresses. With progression, you gradually lose your ability to talk, swallow and move. The disease could also affect other areas of thinking, including judgment and memory.

What does corticobasal degeneration mean?

“Corticobasal” refers to the two parts of your brain the disease affects. “Degeneration” refers to deterioration or loss of function.

The disease affects your:

• Cerebral cortex: This outer layer of nerve tissue aids your memory, learning, voluntary movements and senses.
• Basal ganglia: This group of nerve cells is critical for learning and motor functions.

How common is corticobasal degeneration?

Corticobasal degeneration is a rare brain disease. Diagnosis is challenging. Estimates indicate that as many as 3,000 Americans may have the condition, but only about 700 have received the correct diagnosis.

What are the types of corticobasal degeneration?

Corticobasal syndrome is a term used to specify that the symptoms, taken together, are similar to corticobasal degeneration. Many underlying neurodegenerative diseases can be caused by corticobasal syndrome, including:

• Progressive supranuclear palsy. Approximately 1 in 4 people have a type that resembles progressive supranuclear palsy. It affects balance, eye movement, speech and swallowing.
• Frontotemporal dementia. About 15% of people have frontotemporal dementia. They may struggle to organize their thoughts and behave in inappropriate, uninhibited ways.
• Dementia. An estimated 5% develop a type of dementia that’s similar to Alzheimer’s disease. They have problems with memory and gauging spatial distances between themselves and other people or objects.
• Aphasia. Five percent have language problems or aphasia. They have trouble finding the right words to say and become unable to follow grammar rules.

What causes corticobasal degeneration?

Researchers currently think corticobasal degeneration is a form of frontotemporal degeneration and distinct from Alzheimer’s disease. The breakdown of cells here affects your brain’s frontal and temporal lobes.

The condition occurs when a tau, a protein normally found in brain cells, abnormally clumps together. These clumps, or neurofibrillary tangles, cause your brain cells to degenerate or die. This leads to problems with movement, speech and memory.

Is corticobasal degeneration inherited?

Medical experts don’t know why some people develop corticobasal degeneration. The condition rarely affects members of the same family.

Nine in 10 people with the condition have a gene change (mutation) on chromosome 17. Called the H1 haplotype, this gene change may increase the production of tau, causing the protein to clump together. Or it may cause a carbon atom and hydrogens (a methyl group) to stick to the tau gene, affecting its function. But this gene mutation isn’t the only factor — the same mutation is present in 3 out of 4 people in the general population.

What are the signs of corticobasal degeneration?

Signs of corticobasal degeneration typically appear when you’re in your 60s. Some people show symptoms as early as in their 40s.

The disease affects everyone differently. It often first occurs on one limb or one side of your body and then progresses to the rest of your body. Symptoms worsen as the disease affects more of your brain.

Corticobasal degeneration symptoms include:

• Balance problems and uncoordinated walking gait.
• Difficulty swallowing.
• Memory problems.
• Muscle spasms, muscle twitches (myoclonus) and muscle contractions (dystonia).
• Trouble completing tasks like using utensils or buttoning a shirt.
• Difficulty coordinating fine movements (apraxia).
• Difficulty controlling one limb (alien limb syndrome) and slowed movements (bradykinesia).
• Dementia.
• Slurred or slow speech or difficulty finding the right words (aphasia).
• Tremors.

What other conditions cause corticobasal degeneration symptoms?

Some symptoms of corticobasal degeneration mimic those of other conditions, such as:

• Brain cancer (brain tumor).
• Dementia, especially frontotemporal dementia.
• Alzheimer’s disease.
• Multiple system atrophy.
• Parkinson’s disease.
• Progressive supranuclear palsy.
• Stroke.

How is corticobasal degeneration diagnosed?

To make a diagnosis, your healthcare provider will conduct a physical exam. They carefully evaluate your symptoms. While this condition happens due to a gene change, no genetic test can detect it or predict it.

You may also receive:

• Blood tests.
• Imaging scans such as MRIs or CT scans to look for diseased parts of your brain.
• Neuropsychological testing to assess brain function and memory.
• Cerebrospinal fluid tests to evaluate Alzheimer’s disease-related changes or autoimmune abnormalities.

How is corticobasal degeneration treated?

For corticobasal degeneration, therapies focus on helping compensate for the difficulties with coordination and speech. Medication therapies may help manage muscle jerks or help improve attention or mood-related changes. Treatments for other movement disorders like Parkinson’s disease aren’t often effective. There isn’t a treatment to cure the disease.

Your healthcare provider may recommend:

• Occupational therapy to help you learn new ways to complete daily tasks and maintain independence.
• Physical therapy to help maintain mobility and ease muscle contractions.
• Speech therapy to aid communication and swallowing.

What is the outlook for someone with corticobasal degeneration?

A person with corticobasal degeneration has increasing difficulty taking care of themselves. People may live five to 10 years after the onset of symptoms. Many of these individuals die from disease complications resulting from falls, lack of mobility or infections related to their inability to maintain their personal hygiene.

The disease increases the risk of life-threatening complications, such as:

• Blood clots and pulmonary embolisms.
• Pneumonia and bacterial infections.
• Sepsis.

When should I call the doctor?

Call your healthcare provider if you or a loved one experiences:

• Difficulty walking or controlling limb movements.
• Memory issues or signs of dementia.
• Problems with speech, swallowing or breathing.
• Tremors.

What should I ask my provider?

You may want to ask your healthcare provider:

• Could a different disease cause these symptoms?
• What should I plan for as the disease progresses?
• Which medications or other therapies help?

A note from Cleveland Clinic

Corticobasal degeneration is a rare, slow-progressing brain disease that affects memory, communication and movement. It causes symptoms similar to Parkinson’s disease: muscle spasms and twitches, tremors and slowed movements. It can also affect your ability to talk, swallow and complete simple tasks like buttoning a shirt. As the disease progresses, dementia or memory loss may occur. There currently isn’t a cure for the disease. But therapies for speech and movements may help you maintain independence longer.