Locked-in syndrome is a rare neurological condition in which patients have no voluntary muscle movement with exception of their eyes. Patients are awake and conscious, but do not have the ability to move (with exception of moving their eyes) including swallowing, speaking, or any active range of motion.
Locked-In syndrome is most commonly caused by damage that occurs in the area of the brain called the pons. In Latin, the word "pons" literally means bridge. It connects the medulla oblongata to the cerebral cortex, as well as relays information between the two hemispheres of the brain. This damage is usually caused by either an ischemic stroke (caused by a blood clot) or a hemorrhagic stroke. There is damage to the grey matter of the brain which relays neuronal messages to the body's muscle. This damage also causes deficits in facial control, speaking, and chewing. Other conditions that can cause Locked-In syndrome to occur include brain tumors, nerve inflammation (polymyositis), loss of insulation (myelin sheaths) around nerve cells, and rare disorders such as amyotrophic lateral sclerosis (ALS).
Signs And Symptoms
“Individuals with locked-in syndrome classically cannot consciously or voluntarily chew, swallow, breathe, speak, or produce any movements other than those involving the eyes or eyelids. In some cases, affected individuals can move their eyes up and down (vertically), but not side-to-side (horizontally). Affected individuals are bedridden and completely reliant on caregivers. Despite physical paralysis, cognitive function is unaffected.”
— National Organization for Rare Disorders
Patients with Locked-In syndrome have function of the movement of their eyes as well hearing and sleep-wake cycles. Early speech language therapy is very important. These patients initially communicate through use of their eyes for yes/no. Eyes moving upward signals a "yes" response, and eyes moving downward signals a "no" response.
Diagnosis of Locked-In syndrome is usually made through a series of tests to include the following:
- MRI: This confirms damage to the pons.
- MR angiography: This can show a blood clot in the arteries that perfuse the brainstem.
- EEG: This will reveal normal brain activity as well as normal sleep-wake cycles in the patient.
- Electromyography: This tests shows the electrical activity found within voluntary muscle fibers. This helps to show the ability of nerves to relay impulses to the muscles.
Initially, treatment is focused on resolving the initial issues whether it be a stroke, infection, etc. After the initial treatment is completed, therapy to help the patient communicate is very important. The patient moving their eyes upward for "yes" and downward for "no" is a common method of communication. The next focus should be increasing any small movements the patient may have in a finger or foot. This can be further used for communication if the patient is able to regain enough control.
In a French study of 65 patients, they found that 72% of patients were happy and only 7% of patients had suicidal thoughts. About half of those individuals who were questioned, 55%, had recovered some speech and 70% had recovered some limb movement.
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