Locked-in syndrome

Locked-in syndrome
Other names	Cerebromedullospinal disconnection,[1] de-efferented state, pseudocoma,[2] ventral pontine syndrome
Locked-in syndrome can be caused by a stroke at the level of the basilar artery denying blood to the pons, among other causes.
Specialty	Neurology, Psychiatry

Locked-in syndrome (LIS), also known as pseudocoma, is a condition in which a patient is aware but cannot move or communicate verbally due to complete paralysis of nearly all voluntary muscles in the body except for vertical eye movements and blinking.^[3] The individual is conscious and sufficiently intact cognitively to be able to communicate with eye movements.^[4] Electroencephalography results are normal in locked-in syndrome. Total locked-in syndrome, or completely locked-in state (CLIS), is a version of locked-in syndrome wherein the eyes are paralyzed as well.^[5] Fred Plum and Jerome B. Posner coined the term for this disorder in 1966.^[6][7]

Signs and symptoms

Locked-in syndrome is usually characterized by

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Unlike

• neurotoxic venoms, as they cannot usually cross the blood–brain barrier^{[citation needed}
  ]
• Brainstem stroke^{[citation needed]}
• Diseases of the circulatory system
• Medication overdose[
  examples needed
  ]
• Damage to nerve cells, particularly destruction of the
  myelin sheath, caused by disease or osmotic demyelination syndrome (formerly designated central pontine myelinolysis) secondary to excessively rapid correction of hyponatremia [>1 mEq/L/h])^[10]
• A stroke or brain hemorrhage, usually of the basilar artery^{[citation needed]}
• Traumatic brain injury^{[citation needed]}
• Result from lesion of the brainstem

Diagnosis

Locked-in syndrome can be difficult to diagnose. In a 2002 survey of 44 people with LIS, it took almost three months to recognize and diagnose the condition after it had begun.^[12] Locked-in syndrome may mimic loss of consciousness in patients, or, in the case that respiratory control is lost, may even resemble death. People are also unable to actuate standard motor responses such as withdrawal from pain; as a result, testing often requires making requests of the patient such as blinking or vertical eye movement.^{[citation needed]}

Brain imaging may provide additional indicators of locked-in syndrome, as brain imaging provides clues as to whether or not brain function has been lost. Additionally, an EEG can allow the observation of sleep-wake patterns indicating that the patient is not unconscious but simply unable to move.^[13]

Similar conditions

• Amyotrophic lateral sclerosis
  (ALS)
• Bilateral brainstem tumors
• Brain death (of the whole brain or the brainstem or other part)
• Coma (deep or irreversible)
• Guillain–Barré syndrome
• Myasthenia gravis
• Poliomyelitis
• Polyneuritis
• Vegetative state (chronic or otherwise)

Treatment

Neither a standard treatment nor a cure is available. Stimulation of muscle reflexes with electrodes (

It is extremely rare for any significant motor function to return, with the majority of locked-in syndrome patients never regaining motor control. However, some people with the condition continue to live for extended periods of time,[15]^[16] while in exceptional cases, like that of Kerry Pink,^[17] Gareth Shepherd,^[18] Jacob Haendel,^[19] Kate Allatt,^[20] and Jessica Wegbrans,^[21] a near-full recovery may be achieved with intensive physical therapy.

Research

New brain–computer interfaces (BCIs) may provide future remedies. One effort in 2002 allowed a fully locked-in patient to answer yes-or-no questions.^[22][23] In 2006, researchers created and successfully tested a neural interface which allowed someone with locked-in syndrome to operate a web browser.^[24] Some scientists have reported that they have developed a technique that allows locked-in patients to communicate via sniffing.^[25] For the first time in 2020, a 34-year-old German patient, paralyzed since 2015 (later also the eyeballs) managed to communicate through an implant capable of reading brain activity.^[26]

See also

• Akinetic mutism
• List of people with locked-in syndrome
• The Diving Bell and the Butterfly: memoirs of journalist Jean-Dominique Bauby about his life with the condition
• Johnny Got His Gun, novel about a soldier who loses his limbs and senses after being wounded fighting in WWI
• One (Metallica song), song interpretation of Johnny Got His Gun

References