Locked-in Syndrome (LiS)

Locked-in syndrome (LiS) is a rare neurological disorder that causes paralysis of voluntary muscles, except for those that allow you to move your eyes up and down. People with locked-in syndrome are conscious, alert and have their usual thinking and reasoning abilities. But they can’t show facial expressions, talk or move.

People with LiS can hear and typically communicate through purposeful eye movements, blinking or both. They can also use assistive technologies to communicate.

Damage to a specific part of your brainstem, known as the pons, causes this syndrome.

Anyone can develop LiS. It’s usually the result of underlying disease, such as stroke or a brain tumor. Because LiS may go unrecognized or misdiagnosed, it’s hard for researchers to know the actual number of cases each year. But they agree that it’s rare.

Types of this condition

Locked-in syndrome has three main types, or forms, including:

• The classical form: You have total immobility (lack of voluntary movement). But you can move your eyes up and down, blink and maintain your usual cognitive abilities. You can also hear.
• The incomplete form: This type of LiS is just like the classical form, except you have some sensation and movement functions.
• The total immobility form: You have complete body paralysis and loss of eye movement. But you have your usual cognitive abilities. Healthcare providers can tell that a person with this form still has cognitive function by using a test that measures brain waves.

Symptoms of locked-in syndrome

The effects of locked-in syndrome on your body vary slightly depending on which type you have. Healthcare providers often first think people with this syndrome are in a coma before they test for consciousness.

Most people with locked-in syndrome cannot:

• Make any body movements below their eyes
• Make facial expressions (like smile)
• Speak
• Chew
• Swallow

Most people with LiS can:

• Blink
• Move their eyes up and down (but not side to side)

All people with locked-in syndrome can:

• Hear
• Understand people talking or reading to them
• Think and reason
• Have sleep-wake cycles

Depending on which form of LiS you have, you may or may not feel physical pain. If you have the total immobility form, you won’t feel pain due to total paralysis. If you have the incomplete form, you may feel pain and other sensations in certain areas of your body.

Locked-in syndrome causes

Damage to a specific part of your brainstem called the pons causes locked-in syndrome.

Several specific conditions and situations can damage your pons, causing locked-in syndrome. The most common cause is stroke affecting certain motor tracts in your brainstem, such as the corticospinal, corticopontine or corticobulbar tracts..

Other less common causes of damage to your pons that can lead to LiS include:

• Infection in certain portions of your brain
• Tumors or masses on your pons or brainstem
• Demyelination, which is the loss of the protective layer (myelin) that surrounds nerve cells
• Certain conditions, like amyotrophic lateral sclerosis (ALS) and Guillain-Barré syndrome
• Trauma (injury) to your pons
• Substance use, especially cocaine

Most cases of locked-in syndrome aren’t preventable. But your risk of it may increase if you have stroke risk factors, like high blood pressure.

Complications of this condition

With LiS, you generally retain your mental abilities. But some people with LiS develop issues with:

• Complex sentence comprehension
• Mental math
• Problem solving
• Working memory
• Impulse control
• Executive functioning

Locked-in syndrome can lead to death. This is more likely to happen when the symptoms first appear (the acute phase). Death is also more likely when a major stroke is the underlying cause. This often also suppresses your breathing responses.

How doctors diagnose locked-in syndrome

Locked-in syndrome can be difficult to diagnose or take a while to diagnose correctly. A large part of getting a diagnosis is ruling out other conditions that have similar symptoms. Providers also need to find the cause of the syndrome.

Tests providers use include:

• MRI or CT scan: These can show if you have damage to your pons and/or other areas of your brain.
• Cerebral angiography: This test can reveal if you have a blood clot in the arteries of your brainstem or somewhere else in your brain.
• Electroencephalogram (EEG): This test measures the electrical activity of your brain. It can help providers determine if you have normal brain activity and sleep-wake cycles. These distinguish LiS from other conditions.
• Evoked potentials: These tests measure electrical activity in certain areas of your brain and spinal cord in response to stimulation.
• Electromyography: This test measures how well your muscles and nerves work. It can rule out damage to your muscles and nerves (not your brain).
• Blood tests: A metabolic panel can help determine if pontine myelinolysis is the cause.
• Cerebrospinal fluid (CSF) exam: This test can help determine if an infection or autoimmune condition is causing your symptoms.

How is locked-in syndrome treated?

There’s no cure or specific treatment for locked-in syndrome other than treating the cause and preventing further complications.

Management includes supportive therapy and communication training. Intensive rehabilitation may help you recover some movement function.

Supportive therapy

Supportive therapy for breathing and feeding is very important, especially early on. You’ll likely need an artificial aid for breathing and a tracheostomy (a tube going in your airway through a small hole in your throat).

Eating and drinking using your mouth isn’t safe with LiS. So, you may have a small tube inserted in your stomach called a gastrostomy tube to get food and water.

Other supportive therapies include:

• Preventing complications due to immobilization, like pneumonia, UTIs and deep vein thrombosis
• Preventing pressure injuries (bedsores)
• Physical therapy to prevent limb contractures
• Rehabilitation to help with voluntary movements that remain or recover

Communication training

Speech therapists can help you communicate more clearly with eye movements and blinking. The method of communication is unique to each person.

For example, looking up could mean “yes” and looking down could mean “no” or vice versa. You may also form words and sentences by signaling different letters in the alphabet as someone lists each letter.

Electronic communication devices, like infrared eye movement sensors and computer voice prosthetics, may also help you communicate more freely and use the internet.

New communication technologies, like brain-computer interfaces (BCIs), are constantly emerging. Keep in contact with your healthcare team to learn about what’s available.

Can a person recover from locked-in syndrome?

Each case is different. A substantial recovery of movement is possible and can continue over the years. For example, you may be able to move your head or arm eventually. But it’s highly unlikely that you’ll return to how your body moved before LiS.

According to one study, the likelihood of recovery is better in those who have a nonvascular cause of LiS (like a tumor or infection) compared to vascular causes (like a stroke).

Quick diagnosis and treatment can help increase your odds of recovery. Starting rehabilitation as soon as possible is also key.

What can I expect if I have this condition?

The prognosis (outlook) for people with locked-in syndrome depends on the cause and form of the condition. The level of support and care you receive also matters. Your healthcare team will be your guide throughout your recovery. You’ll likely need years of rehabilitation.

Studies show that people with LiS report having a meaningful life. Especially when they have proper access to services and technology to help them at home and in their community.

Many people with LiS can use a motorized wheelchair and a computer with adaptive technology.

How long can you live with locked-in syndrome?

It’s impossible to predict life expectancy because each case is different. Some people with locked-in syndrome don’t live beyond the early stage of the condition due to complications. But others may live for another 10 to 20 years.