What Is Corticobasal Syndrome?

Corticobasal Syndrome is a rare degenerative neurological disease. The condition causes atrophy, or shrinkage, of certain areas in the brain and degeneration and eventual death of the nerve cells. The degeneration affects areas of the brain that are responsible for information processing and movement. Corticobasal syndrome causes difficulties in movement on one or both sides of the body. Additionally, it also causes difficulties with muscle stiffness, swallowing, poor coordination, thinking, memory, and speaking.

The two main areas of the brain corticobasal syndrome affects includes:

• Cerebral cortex. This is the outer layer of nerve tissue that is responsible for aiding in voluntary movement, memory, learning, and senses.
• Basal ganglia. This group of nerve cells is responsible for motor functions and learning.

There are several types of neurodegenerative disorders that are caused by corticobasal syndrome, including:

• Progressive supranuclear palsy
• Frontotemporal dementia
• Dementia
• Aphasia

Corticobasal syndrome affects 5 in every 100,000 people in the general population and impacts females slightly more than males. The general age range symptoms are most likely to develop is 50-70 years old, although there have been reported cases of corticobasal syndrome impacting people under the age of 40.

Signs and Symptoms

Symptoms of corticobasal syndrome tend to progress over 6-8 years and include:

• Difficulty with movement on one or both sides of the body that gets worse over time
• Balance issues
• Coordination problems (specifically fine motor skills)
• Stiffness
• Abnormal postures of hands and feet (clenched fists)
• Tremors
• Difficulty swallowing
• Muscle spasms or jerking, twitches, and contractions
• Abnormal eye movements
• Memory problems
• Issues with information processing and thinking
• Behavioral changes
• Trouble with speaking (slurred, slowed, or halting speech)
• Losing the ability to walk

Causes

The cause of corticobasal syndrome is not clearly known. Research has shown that people with this condition have a significant buildup of tau protein in the brain. As the protein collects in the brain nerve cells, it causes the cells to degenerate and die. Cell death is what leads to brain shrinkage (atrophy). Research has also discovered a buildup of amyloid plaques, similar to those found in Alzheimer’s disease, in some cases. Atypical Alzheimer’s has also been shown to be a possible cause of corticobasal syndrome.

Corticobasal syndrome is not considered an inherited disease, although research has found a gene mutation on chromosome 17 (H1 haplotype) that may increase the production of tau protein, causing it to buildup in the nerve cells. The gene mutation may also cause a carbon atom and hydrogens to stick to the tau gene, negatively impacting its functioning. It is important to note that this gene mutation impacts 3 out of every 4 people in the general population and does not necessarily indicate that corticobasal syndrome will develop.

Risk Factors

Since no definitive cause for corticobasal syndrome has been determined, risk factors are also somewhat unclear. Research is currently investigating whether environmental factors (exposure to chemicals or toxins) or traumatic brain injuries have an impact on the development of corticobasal syndrome. Additionally, research has indicated that a gene mutation (gene 17) may also play a role in the development of corticobasal syndrome.

Diagnosis

To diagnose corticobasal syndrome, your doctor will evaluate your symptoms, take a thorough medical history, and perform a physical exam. Although genetic testing cannot predict or detect this condition, there are other testing measures that can help to diagnose corticobasal syndrome.

Tests include:

• Blood tests. Blood tests assess for any abnormalities in the blood and help to rule out other conditions.
• Imaging scans (MRI, CT scans). Imaging tests can indicate whether there is disease or degeneration in any parts of the brain.
• Neuropsychological testing. These tests help to detect and assess brain functioning and memory issues.
• Cerebrospinal fluid tests. This test assesses for any Alzheimer’s disease-related changes and for autoimmune abnormalities.

Although imaging tests can detect neurodegeneration, they cannot reliably distinguish corticobasal syndrome from other neurodegenerative diseases. Often, diagnosis of corticobasal syndrome is confirmed during an autopsy examination where doctors can view hallmark traits of the disease.

Treatment

Currently, there are no treatments that can cure or slow the progression of corticobasal syndrome. Treatments focus on managing some of the symptoms related to movement, muscle jerking and stiffness, and some of the cognitive issues and mood issues. Medication has been used to treat movement related symptoms and muscle rigidity, but the medications have failed to show consistent effective results. Other treatments, such as physical therapy, occupational therapy, and speech therapy are often utilized to help manage some of the symptoms as well.

Prevention

There is no known prevention for corticobasal syndrome.

Complications

The brain degeneration and loss of brain functioning that occurs with corticobasal syndrome make it increasingly difficult for people with the disease to take care of themselves and function in their daily life. People usually live for 5-10 years after onset of the disease and typically die from complications of the disease.

Complications include:

• Blood clots and pulmonary embolisms
• Pneumonia or other bacterial infections
• Sepsis