Cerebellar Atrophy

Cerebellar atrophy means that the cerebellum, the part of the brain at the back of the head that coordinates movement and balance, has shrunk because nerve cells in it have been damaged or lost. It is usually seen on an MRI or CT brain scan.

Cerebellar atrophy is not a single disease. It is a finding that can have many different causes, some inherited and some acquired during life. The cause matters, because it determines how the condition will progress and whether anything can be done to treat it.

What causes cerebellar atrophy?

Inherited (genetic) causes include:

• Spinocerebellar ataxias (SCAs), a group of more than 40 inherited conditions, usually passed on from one parent, that typically start in adulthood
• Friedreich's ataxia and other recessive ataxias, which usually start in childhood or adolescence and need a changed gene from both parents
• Other rarer genetic conditions, including some that affect the body's energy production (mitochondrial disorders)

Acquired causes include:

• Long-term heavy alcohol use, one of the most common causes in adults
• Stroke or bleeding affecting the cerebellum
• Multiple sclerosis
• Vitamin deficiencies, such as vitamin B1 (thiamine), vitamin B12 or vitamin E
• An underactive thyroid
• Some medicines and toxins
• Gluten ataxia, an immune reaction to gluten
• Rarely, an immune reaction triggered by a cancer elsewhere in the body (paraneoplastic cerebellar degeneration)
• Degenerative conditions such as multiple system atrophy

In some people, no cause can be found even after thorough testing. This is sometimes called idiopathic or sporadic late-onset cerebellar ataxia.

Symptoms

Because the cerebellum coordinates movement, the main symptom of cerebellar atrophy is ataxia, a loss of coordination. This can cause:

• Unsteady walking and poor balance, with a higher risk of falls
• Clumsiness and difficulty with precise hand movements
• Slurred or slow speech
• Jerky or abnormal eye movements, sometimes with double vision
• Difficulty swallowing in more advanced cases

Some causes also bring other symptoms, such as numbness from nerve damage, stiffness, tremor, or changes in thinking and memory.

How quickly symptoms develop varies enormously. A stroke can cause symptoms within minutes. Alcohol-related or vitamin-related atrophy develops over months or years. Inherited ataxias usually progress slowly over many years. In some people, mild atrophy is seen on a scan with few or no symptoms.

Diagnosis

A neurologist will ask about symptoms, family history, alcohol use and medicines, and carry out a neurological examination. Tests may include:

• An MRI scan to look at the cerebellum and the rest of the brain
• Blood tests for vitamin levels, thyroid function, coeliac disease antibodies and other treatable causes
• Genetic testing if an inherited cause is suspected

Treatment and outlook

The outlook depends entirely on the cause:

• Some causes can be treated or stopped. Stopping alcohol can halt alcohol-related damage and sometimes lead to improvement. Correcting a vitamin deficiency or an underactive thyroid, a strict gluten-free diet in gluten ataxia, or stopping a responsible medicine can stabilise or improve symptoms.
• Inherited and degenerative causes currently have no cure and usually progress slowly. Life expectancy varies widely between conditions: some shorten life, while others have little effect on it.

Whatever the cause, physiotherapy, speech and language therapy, occupational therapy and mobility aids can help people stay safe, active and independent. Avoiding alcohol is sensible for anyone with cerebellar atrophy, because alcohol can make coordination worse. Vitamin supplements only help if a person is actually deficient, so it is best to have levels checked rather than take them routinely.

Regular follow-up with a neurologist, ideally one with expertise in ataxia, is important for monitoring and for accessing new treatments and research as they become available.