What Is Locked-in Syndrome?
Patients with the locked-in syndrome (pseudocoma) are awake and conscious but selectively de-efferent, meaning they are unable to produce speech, limb, or facial movements. The most common cause is acute ventral pontine lesions. People with brain stem injuries sometimes remain unconscious for days or weeks, requiring artificial respiration before gradually awakening but remaining paralyzed and mute, seemingly resembling patients in a vegetative state or akinetic mutism. Because attention fluctuates and eye movements are inconsistent, tiny, and rapidly exhausted, eye-coded communication and evaluation of cognitive and emotional functioning are severely constrained in acute locked-in syndrome (LIS). More than half of the time, it is the family, not the physician, who notices that something is wrong and the patient is awake.
What Causes Locked-in Syndrome?
Damage to the pons, a particular portion of the brainstem, is the most common cause of the locked-in syndrome. Between the cerebrum, spinal cord, and cerebellum, the pons houses critical neural networks. All motor fibers flowing from gray matter in the brain to the body's muscles through the spinal cord are disrupted in locked-in syndrome, as are the regions in the brainstem that regulate facial control and speech. The most common cause of pons damage is tissue loss owing to a lack of blood flow (infarct) or bleeding (hemorrhage); trauma is a less common cause. An infarct can be caused by a number of things, including a blood clot (thrombosis) or a stroke. Infection in some parts of the brain, malignancies, loss of the protective insulation (myelin) that surrounds nerve cells (myelinolysis), nerve inflammation (polymyositis), and certain illnesses such as amyotrophic lateral sclerosis (ALS) are all possible causes of locked-in syndrome.
What Are the Types of Locked-in Syndrome?
Locked-in syndrome is classified into three categories or forms:
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The total immobility variant of the locked-in syndrome is characterized by complete physical paralysis and lack of eye movement but normal cognitive functioning. By analyzing cortical function with an electroencephalogram (EEG), healthcare providers can detect if a person with this kind still maintains cognitive (thinking and reasoning) functions.
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The traditional form of the locked-in syndrome presents complete immobility (lack of voluntary movement), but the patient can move their eyes vertically up and down, blink, and keep their normal cognitive functions. They may hear as well.
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The incomplete variant of the locked-in syndrome is similar to the classical form, except that certain sections of the body can have sensation and movement functions.
What Are the Signs and Symptoms of Locked-in Syndrome?
Depending on whatever sort of locked-in syndrome the patient has, the impacts on their body differ slightly. Before acknowledgment of consciousness, people with locked-in syndrome are frequently considered to be in a coma. Most patients suffering from the locked-in syndrome are not able to deliberately or consciously:
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Speak.
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Swallow.
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Chew.
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Make any movements beneath their eyes.
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Make appropriate facial expressions.
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Make limb movements due to quadriplegia or limb paralysis.
The majority of persons who have locked-in syndrome can:
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Blink.
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Move their eyes vertically (up and down) rather than side to side (horizontally or laterally).
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Hear.
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Think and reason as they did before they encountered locked-in syndrome.
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Possess sleep-wake cycles.
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Understand what people are saying or reading to them.
How to Diagnose Locked-in Syndrome?
As some people may be comatose for a long time before developing locked-in syndrome, it may be difficult to diagnose locked-in syndrome in some patients at first; some patients with a recent onset stroke may resemble persons with locked-in syndrome. If vertical eye movement and blinking are not evaluated in seemingly unresponsive patients, the diagnosis may be missed. Magnetic resonance imaging (MRI) of the precise brain area that indicates damage can reveal evidence of locked-in syndrome. Positron emission tomography (PET) and single-photon emission computerized tomography (SPECT) brain scans can also be used to assess the patient's abnormalities. Approximately half of the patients with locked-in syndrome are identified by family members who notice that the patient is awake and able to respond (communicate), mainly through eye movements. Electroencephalograms (EEG) and other tests reveal typical sleep-wake rhythms.
How Is Locked-in Syndrome Treated?
Other than addressing the cause and preventing subsequent symptoms, there is no cure or particular therapy for the locked-in syndrome. Communication training and supportive therapy are used to treat the locked-in syndrome.
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Communication Training: With eye movements and blinking, speech therapists can assist patients with locked-in syndrome to communicate more clearly. Each person's communication style is distinct. Looking up, for example, may imply "yes," but looking down could mean "no," or vice versa. People with locked-in syndrome can also build words and sentences by pointing to different letters in the alphabet while someone else lists each letter audibly. Electronic communication technologies, such as infrared eye movement sensors and computer voice prostheses, allow patients with locked-in syndrome to communicate more effortlessly and have internet access in addition to coded eye movements.
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Supportive Treatment: Supportive breathing and feeding therapy are critical, especially early on. Locked-in syndrome patients frequently require artificial respiration and will undergo a tracheotomy where a tube goes into their airway through a small hole punctured in their throat. People with the locked-in syndrome often have a tiny tube put in their stomach called a gastrostomy tube or a G-tube to receive food and water because eating and drinking with their mouth is dangerous.
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Other possible therapies include preventing pneumonia, urinary tract infections (UTI), and thrombosis resulting from immobility. Pressure injury prevention, for example, bedsores and preventing limb contractures which are caused due to limitations in the range of motion of the joint, muscle, or soft tissue through physical therapy. Physical therapy is used to rehabilitate any little voluntary motions that remain or can be recovered.
Conclusion:
People with locked-in syndrome report leading happy and meaningful lives, especially when they have access to appropriate social services and adapted technology that allows them to function normally at home and in their communities. Many patients with locked-in syndrome can benefit from a motorized wheelchair and an adaptable computer. Finding ways to communicate, whether through eye motions or assistive technology, is also critical. While caring for someone who has locked-in syndrome, it is critical to advocate for them so that they receive the finest medical care and have access to technologies that can help them communicate and become more self-sufficient.
