The death of the Rev. Jesse Jackson has put a spotlight on progressive supranuclear palsy, a rare degenerative brain disorder.

The condition affects body movements, walking, balance and even eye movements, according to the National Institutes of Health.

Damage to the nerve cells in the areas of the brain that control not only movement but also thinking.

It is different from Parkinson’s disease, which Jackson had initially been diagnosed with, but some of the symptoms are similar.

Progressive supranuclear palsy, or PSP, symptoms begin in the mid-to-late 60s, later than Parkinson’s disease typically develops. Cure PSP says it can start as early as the 40s.

About 1 million people have Parkinson’s disease in the U.S., but only 30,000 have PSP. That number may be underestimated due to misdiagnosis of either Parkinson’s or frontotemoral dementia, Cure PSP said.

Symptoms of progressive supranuclear palsy

People with PSP may have issues with balance, difficulty walking, difficulty swallowing, slurred speech, and issues with eye movements.

But the disease does not just affect mobility; it can also affect a person’s mood, behavior and thinking, the NIH said.

As for eyes, PSP can cause them to move slowly. A person may have trouble looking up or down, have issues controlling their eyelids, including involuntary eyelid closure, decreased blinking, or difficulty opening their eyes. They may also move their head to look in different directions, not just their eyes.

PSP will also affect a person’s mood and thinking.

Symptoms may include:

• Depression
• Lack of motivation
• Changes in judgment, insight, and problem-solving
• Difficulty finding words
• Forgetfulness
• Loss of interest in activities the person used to enjoy
• Increased irritability
• Sudden laughing, crying, or angry outbursts
• Personality changes
• Slowed, slurred, or monotone speech
• Difficulty swallowing
• Mask-like facial expressions
• Sleep problems

Differences between PSP, Parkinson’s

While they may appear similar, there are several differences between PSP and Parkinson’s disease.

One of the biggest markers of PSP is early, unprovoked falls, according to the American Parkinson Disease Association. People fall backward and cannot catch themselves. Falling in Parkinson’s patients typically happens when the disease is more advanced.

According to the NIH:

People with PSP not only tend to lean backward, but they also extend their necks, while people with Parkinson’s lean forward.

Speech and swallowing issues are more common and severe in PSP and show up earlier than in Parkinson’s.

Parkinson’s patients have tremors in most cases. Tremors are not usually part of the PSP diagnosis.

Levodopa therapy will help many Parkinson’s patients, but won’t have much of an effect on PSP patients.

PSP patients typically have an accumulation of tau in their affected brain cells. Parkinson’s patients have an accumulation of alpha-synuclein.

Diagnosis and treatment

There are no tests to definitively diagnose PSP, but exams will help rule out other conditions. Imaging can show brain shrinkage near the brain stem and can help doctors see brain activity in other parts of the brain.

The NIH said no treatment stops or slows PSP progression and symptoms don’t respond well to medications.

In some people, levodopa can treat slowness, stiffness and balance problems, but the effects are minimal and short-lasting for most.

Botulinum toxin injections may help with eye closing, while some antidepressants may help with more than just depression, including pain relief and decreasing drooling.

Non-drug treatments may include weighted walking aids to help lessen the risk of falling backward, special glasses to help reduce issues with looking down and exercise to keep joints moving.

For people with problems swallowing and who are at risk of choking, a tube can be placed into the stomach to allow them to get nutrients but not have to chew or swallow.

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