Locked-in syndrome is a rare but serious brain condition in which you lose your ability to move and speak. You’re still conscious and, in most cases, can move your eyes and blink. Though there’s no cure, some treatments can improve your quality of life.

Locked-in syndrome is a rare condition that occurs following damage to your brainstem. Although people with locked-in syndrome are paralyzed and unable to speak, the condition doesn’t interfere with thinking or moving their eyes.

This article provides an overview of locked-in syndrome, including symptoms, causes, diagnosis, and treatment.

Locked-in syndrome is associated with damage to a region of the brainstem called the pons.

Your brainstem is a branch-like structure that connects your brain and spinal cord. The pons, found in the middle of your brainstem, is an important hub for nerves that transmit sensory and motor information from the face and body to the brain and vice versa.

In locked-in syndrome, the pons sustains damage due to:

  • lack of blood flow
  • infection
  • injury
  • a mass
  • a disorder that affects the myelin sheath

Some conditions that researchers have linked to locked-in syndrome include:

Strokes are the most frequent cause of locked-in syndrome, followed by TBIs. Other causes are less common.

Anyone can get locked-in syndrome. With that said, you could be at an increased risk if you already have or are at risk of developing any of the conditions listed above.

For example, people at an increased risk of stroke, such as older adults with high blood pressure, may be slightly more likely to develop locked-in syndrome.

But keep in mind that while hundreds of thousands of people have strokes each year, there are only a handful of new cases of locked-in syndrome. In other words, the risk of someone developing locked-in syndrome after a stroke is still very low.

How rare is locked-in syndrome?

Locked-in syndrome is extremely rare. According to an estimate from the Genetic and Rare Diseases Information Center, fewer than 1,000 people in the United States have it.

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Locked-in syndrome causes physical paralysis but doesn’t affect cognitive function.

In other words, although people with the syndrome cannot speak, breathe, chew, or drink, they’re conscious and aware of what’s going on around them. They can see, hear, and think.

There are three types of locked-in syndrome, according to the level of physical paralysis. These include:

  • Classical: With classical locked-in syndrome, you cannot move your body but can still move your eyes and blink.
  • Incomplete: With incomplete locked-in syndrome, you can make some small movements, in addition to eye movements and blinking.
  • Total immobility: With total immobility locked-in syndrome, you’re completely paralyzed and cannot move your eyes or blink.

Neurologists use several tests to diagnose locked-in syndrome and identify potential causes of brainstem damage.

Electrophysiological studies

Electroencephalography (EEG) is a noninvasive test doctors use to evaluate brain activity and attention. It can show whether someone experiencing physical paralysis is still conscious.

Electromyography (EMG) is a noninvasive test doctors use to diagnose conditions that cause nerve damage, including MS, ALS, and GBS.

Medical imaging

Noninvasive scans, such as computed tomography (CT/CAT) and magnetic resonance imaging (MRI), provide an image of the brain that can help identify the cause of locked-in syndrome.

If a neurologist suspects a stroke, they might also order a scan of your heart, arteries, and blood vessels, known as CT or MR angiography.

Laboratory tests

Laboratory tests doctors use to help diagnose the cause of locked-in syndrome include cerebrospinal fluid (CSF) examination and blood tests. CSF tests can help identify an infection or autoimmune condition. Blood tests provide information about electrolyte and glucose levels.

Locked-in syndrome vs. akinetic mutism and catatonia

During diagnosis, doctors also rule out neurological conditions that cause symptoms similar to locked-in syndrome. For example, your doctor might use tests to rule out akinetic mutism.

Akinetic mutism causes symptoms that may look like locked-in syndrome, but they’re not the same. People with akinetic mutism are conscious but may have extreme difficulties moving and speaking. But unlike people with locked-in syndrome, they’re not physically paralyzed.

Catatonia is another condition that can appear similar to locked-in syndrome. Catatonia is linked to some psychiatric conditions. While people with locked-in syndrome often try to communicate with their eyes, people with catatonia tend not to.

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There’s no cure for locked-in syndrome. But many treatments are available. The treatment will depend on the cause of brainstem damage.

Some conditions, such as strokes and brain injuries, constitute a medical emergency. If that’s the case, a medical team will provide appropriate critical care.

To manage the life threatening effects of locked-in syndrome, a doctor will need to make some urgent medical interventions. These may include inserting a tube for artificial breathing (tracheostomy) and a tube for feeding (gastrostomy).

Once the person’s condition is stable, their medical team will provide treatments to address symptoms, keep them comfortable, and improve their ability to communicate.

Some longer-term treatments for locked-in syndrome include:

  • Physical therapy: Physical therapy includes several techniques to strengthen and stimulate the muscles, including functional neuromuscular stimulation.
  • Respiratory therapy: Respiratory therapy, including breathing and chest exercises, can help people with locked-in syndrome maintain breathing and cardiovascular function.
  • Assisted technologies: Several devices are available to help people with locked-in syndrome communicate. These include infrared eye movement sensors, computer-modulated voice prosthetics, and brain-computer interfaces.

The benefits of these treatments vary depending on which type of locked-in syndrome someone has and how severe their level of immobility is.

Some people with locked-in syndrome regain certain small movements, such as moving their fingers or nodding their head. Most people with locked-in syndrome won’t regain key motor functions, such as speaking, walking, or swallowing.

Despite this, many people with locked-in syndrome report being generally satisfied with their lives.

For example, the authors of a 2015 study assessed the quality of life of 39 people with locked-in syndrome via a questionnaire. They found that 70% of participants reported a stable or improved quality of life over the 6-year study period, and that their level of satisfaction was not dependent on their physical ability.

How can you communicate with someone with locked-in syndrome?

People with locked-in syndrome can hear and understand you, so it’s possible to communicate with them. They can communicate with you via eye movements.

One simple and often-used technique is asking the person to look up to say “yes” and to look down to say “no.” In the long term, assisted technologies can help people with locked-in syndrome communicate.

Do people with locked-in syndrome feel pain?

Some people with locked-in syndrome can feel pain, such as in the case of incomplete locked-in syndrome. For others, pain sensations are limited or nonexistent. Neurologists can run tests to determine whether someone with locked-in syndrome still feels pain.

Does locked-in syndrome come on suddenly or gradually?

Most people with locked-in syndrome gradually regain consciousness after an emergency, such as a stroke or accident. Since they cannot move or speak, they might have difficulty signaling to others that they’re awake and conscious.

Can you prevent locked-in syndrome?

It’s not possible to prevent locked-in syndrome. You can take steps to prevent some of the causes of locked-in syndrome. For instance, you can reduce your risk of stroke by eating a balanced diet, quitting cigarettes if you smoke, and limiting alcohol intake.

Locked-in syndrome is a rare condition. It’s usually due to damage to the brainstem from another condition, such as a stroke, brain injury, or tumor.

People with locked-in syndrome are conscious but cannot speak or move their bodies. They may still be able to move their eyes and blink.

Treatments for locked-in syndrome involve first addressing the underlying condition. In the long term, various therapies can help people with locked-in syndrome communicate and regain partial autonomy.