by Sophia Reiner
“I'm just left trapped inside this body” (Chisholm, 2015). Imagine waking up from a coma. Upon regaining consciousness, the cloud fogging your brain disappears and you expect your hibernating body to re-enter into the continuous routine of performing voluntary movements. However, while your cognitive abilities may be ordering your limbs to stir or your mouth to form words, your external functions do not respond. Your awakened mind is essentially trapped in the prison of your body, and unable to communicate with anyone on the outside; this condition is called the locked-in syndrome.
Locked-in syndrome is a neurological disorder affecting all voluntary muscles but the eyes. While the person with the disorder is still conscious and has a properly working thought process, their muscles are paralysed. Discovered by neurologists Fred Plum, and Jerome B. Posner in 1966, locked-in syndrome was defined in The Diagnosis of Stupor and Coma as a state where “paralysis of all four extremities and the lower cranial nerves without interfering with consciousness” occurs. Furthermore, it is possible for the patients to be “left with the capacity to use vertical eye movements and blinking to communicate their awareness of internal and external stimuli” (Plum & Posner, 1966).
Locked-in syndrome is rare, but the number of affected individuals cannot be accurately ascertained due to the prevalence of unrecognition or misdiagnosis as a persistent vegetative state (National Organisation for Rare Disorders [NORD]). Essentially, it is uncommon for full motor control to return after contracting the disability as a cure is not available, and the limited number of individuals with locked-in syndrome has made it difficult for effective treatment research.
This uncommon disease is organised into categories based on severity, which is determined by varying causes and the scale of symptoms experienced. Locked-in syndrome cases are classified in stages, for example, patients with incomplete locked-in syndrome have a small remaining quantity of voluntary movement, but are still largely paralysed (Bauer et al, 1979). More severe patients can be diagnosed with the classic form, where the conscious patient has quadriplegia (limb paralysis), anarthria (inability to articulate speech), and is only able to blink and create vertical eye movements. Finally, the most progressed stage of locked-in syndrome is classified as a total form. People affected with total locked-in syndrome have complete consciousness but complete immobility and inability to communicate (NORD).
As a result, these individuals cannot interact with the environment and express their thoughts without advanced technology, making it necessary for continued advancements to be made in this field. Overall, the three classifications stem from similar internal clinical features but are presented with different degrees of external body restrictions.
While thinking and consciousness are maintained, patients with locked-in syndrome can have affected neurological abilities and develop other illnesses as a result. Executive function and perceptual memory have often been detrimentally impacted, however, cases of preserved cognitive abilities have been found, as stated by Eimear Smith and Mark Delargy from the National Rehabilitation Hospital of Dublin. Smith and Delargy also present related neurological complications such as visual difficulties (though, hearing is preserved), vertigo, and emotional lability. According to experimental psychology researcher Jose Leon-Carrion and colleagues, out of 44 patients with locked-in syndrome, memory problems were found in eight, and attention deficits in six; within this group, 39 of the recovered patients have had emotional sensitivity since the onset of the condition. This highlights the significant life-changing consequences of contracting locked-in syndrome and the importance of raising awareness.
Regarding the causes, locked-in syndrome can develop as a result of both internal diseases and external traumas. Locked-in syndrome occurs as a result of damage to the ventral pons, which is located at the bottom of the brainstem and controls neuronal pathways, involuntary actions, hearing, facial sensations, and motor functions (NORD). Locked-in syndrome disrupts these motor fibres in the pathways that run from the brain through the spinal cord to the muscles. To cause the disturbances, an infarct — tissue loss from lack of blood flow — must occur, which can result from a stroke, hemorrhage, or trauma. In addition to traumatic brain injuries, other traumas — tumours, destroyed myelin sheath, and circulatory system diseases — can lead to locked-in syndrome (Smith & Delargy, 2005).
Depending on the cause of the condition, treatment options for locked-in syndrome focus on varying supportive therapies and technological accommodations. As cures are unavailable, supportive therapies for breathing and feeding are prioritised as well as treatment towards the underlying conditions that cause locked-in syndrome (NORD). Furthermore, physical therapy, comfort cases, nutritional support, and prevention of systemic complications like respiratory infections are other general treatments (GARD). But in recent years, brain-computer interfaces (BCIs) have been utilised in assistance alongside these treatments (Brumberg & Guenther, 2010). This technology works to gather patients’ neural activity and translate the thoughts into external devices, such as mouse cursors or robotics. Essentially, as BCIs demonstrate that speech prostheses can replace one’s voice, current technology has been able to adapt to the severe paralysis of people with locked-in syndrome.
Overall, efforts made in locked-in syndrome research demonstrate the necessity of creating methods of communication with the affected individuals. The exhaustion of interacting only through vertical eye movements makes communication difficult, and establishing a system of interpretation can ease this obstacle (Smith & Delargy, 2005). In the modern-day where society is learning to respectfully interact with and include the disabled community, the technological advancements for locked-in syndrome are very significant. For instance, such inclusivity can be demonstrated by giving the patients opportunities for initiating and ending conversations since they cannot effectively ask for attention. In conclusion, by understanding the symptoms of locked-in syndrome and the treatment options, society can learn of the long-term influences of locked-in syndrome, in order to successfully interact with and maintain a successful relationship with affected individuals.
References
Bauer, G., et al. “Varieties of the Locked-in Syndrome.” Journal of Neurology, vol. 221, no. 2, 1979, pp. 77–91., https://doi.org/10.1007/bf00313105.
Brumberg, Jonathan S, and Frank H Guenther. “Development of Speech Prostheses: Current Status and Recent Advances.” Expert Review of Medical Devices, vol. 7, no. 5, 2010, pp. 667–679., https://doi.org/10.1586/erd.10.34.
Chisholm, Nick, and Grant Gillett. “The Patient's Journey: Living with Locked-in Syndrome.” BMJ, vol. 331, no. 7508, 2005, pp. 94–97., https://doi.org/10.1136/bmj.331.7508.94.
León-Carrión, José, et al. “Survey: The Locked-in Syndrome: A Syndrome Looking for a Therapy.” Brain Injury, vol. 16, no. 7, 2002, pp. 571–582., https://doi.org/10.1080/02699050110119781.
“Locked in Syndrome.” NORD (National Organization for Rare Disorders), 12 Mar. 2018, https://rarediseases.org/rare-diseases/locked-in-syndrome/.
“Locked-in Syndrome.” Genetic and Rare Diseases Information Center, U.S. Department of Health and Human Services, https://rarediseases.info.nih.gov/diseases/6919/locked-in-syndrome.
Plum, Fred, and Jerome B. Posner. The Diagnosis of Stupor and Coma. Oxford University Press, 2000.
Smith, Eimear, and Mark Delargy. “Locked-in Syndrome.” BMJ, vol. 330, no. 7488, 2005, pp. 406–409., https://doi.org/10.1136/bmj.330.7488.406.
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