Introduction

Imagine lying in a hospital bed, completely powerless and unable to move. What would that feel like? You might think that you will not feel anything, no thoughts, no sensations, you could be blissfully unaware of what your body is doing, maybe even be unaware of your existence.

Now imagine if all your brain power was preserved- you can feel your surroundings, even be able to hear the people around you. You can have dreams, thoughts and emotions. But you cannot do anything about those. Not just being unable to move your arms and legs, but not even being able to speak, do your favourite activities, not even be able to express your powerlessness. 

Such is the plight of patients suffering from locked-in syndrome. This unique suffering is quite frightening to think about. It is one of the most misunderstood neurological conditions that medical science is struggling with. Understanding this condition can help us provide better care to those who are struggling. Let us delve into this and understand how powerful the human mind really is.

What is locked-in syndrome?

The term locked-in syndrome (LIS) was first introduced by the scientists Plum and Posner in the year 1983. They spoke about patients who are awake and conscious but have only selective powers left.¹ The American Congress of Rehabilitation Medicine (1995) defined LIS as a neurological impairment which is characterised by the inability to open your eyes, quadriparesis, and aphonia (complete inability to speak). Some patients can retain their speaking ability, but it is severely reduced (hypophonia). They are “locked in” to their bodies.

This is different from being in a vegetative state or a coma, as in these conditions, awareness is not retained. Thus, other words used interchangeably with LIS in scientific literature are “de-efferented state" and "pseudocoma".²

What causes locked-in syndrome?

Commonly, locked-in syndrome is caused by an acute stroke which is limited to an area of the brainstem known as the ventral pons.³ Some chronic conditions, which can also eventually cause LIS, are amyotrophic lateral sclerosis (ALS).⁴ Other causes include traumatic brain injury, infections or tumours pressing on the brain stem, lack of oxygen to the brain after cardiac arrest.

How can someone be awake and still?

It feels a little impossible to imagine how a person who looks unresponsive can think and feel like a normal person. But that is exactly what is found in locked-in syndrome. The part which is affected in this condition is the brainstem. The brainstem connects the spinal cord to the rest of the centres in the brain. It contains pathways for voluntary movement and houses the reticular formation, which is the centre for consciousness and alertness (5). When a stroke damages this region, the motor pathways are disrupted. However, the cognitive part of the brain (the cerebral cortex) remains untouched. Even though the causes can be different, the result is usually the same,with paralysis of almost all muscles, except those controlling vertical eye movement or blinking.⁶

Although patients are conscious, features like attention, intellectual ability, perception, and memory can be affected. Thoughts still form, emotions are still felt, memories can still be accessed, and language and reasoning abilities remain functional. 

How do people with LIS communicate?

Communication in LIS is challenging but not impossible. Most individuals retain control over eye movements, including vertical gaze and blinking. This can become their primary way of interacting with people around them. Caregivers and healthcare workers can use whiteboards to write yes or no questions, which can be answered by the patient by blinking. There can also be codes assigned to the preserved eye responses, which can convey specific messages.⁷

One of the biggest breakthroughs that has dramatically opened up new possibilities of communication in such patients is the development of brain-computer interfaces (BCIs). This technology uses the patient’s own thoughts by using an EEG (electroencephalogram) to control a computer/ other device. The cursor on a computer screen can be used to select letters or other symbols.⁸ Functional MRI (fMRI) can also be used now to communicate. This imaging modality has also been used to prove that awareness can still exist even in cases of extreme physical limitations.⁹

What’s life like inside a motionless body?

It is hard to empathise with people in such a difficult state. However, we are blessed to have a first-hand memoir by one such patient at our disposal. This book can give us an insight into how rich the internal world of a patient can be, despite their debilitating medical condition. The editor-in-chief of French Elle, Jean-Dominique Bauby, suffered a stroke in the year 1995, which resulted in locked-in syndrome when he was just 43 years old. Bauby wrote this book with great difficulty, by blinking his left eyelid to point out letters to a device.¹⁰ Despite total physical paralysis, the writer’s mind remained vivid, alert, and imaginative. He describes his mind as akin to a butterfly, symbolising its freedom to roam, dream, and remember. 

How is it diagnosed?

LIS can often be misdiagnosed as a coma or vegetative state, especially if intensive neurological examination and investigations are not undertaken. It can lead to serious consequences, like untimely withdrawal of life-sustaining care.^7,8 To accurately diagnose LIS, doctors use a combination of radiological modalities. MRI to identify damage to the ventral pons, which is indicative of LIS.¹¹, EEG and evoked potentials to assess and confirm preserved cortical function.⁹

Is there any recovery?

Recovery in locked-in syndrome relies on numerous factors, like the cause, location, and extent of the lesion in the brain, as well as the patient's age and timing of initiating treatment.² Some patients can regain some movements, like twitches in the fingers or facial expressions.⁶ Even though complete motor recovery is rare, a relatively good quality of life can also be achieved with the help of strong rehabilitative support. However, complete motor recovery is rare. Rehabilitation often involves a multidisciplinary team, including neurologists, physiotherapists, psychologists, and speech therapists, all working together to maximise patient function and comfort.¹²

Emotional and ethical considerations

LIS raises considerable ethical and emotional dilemmas, especially if the patient cannot communicate enough.³ A very concerning aspect is the informed consent. Can a patient accurately convey their wishes with such limited ways of communication? It is a very important debate.¹³ Another perspective is that of end-of-life care decisions. Is there any point in continuing life-sustaining treatment when a person is unable to speak or move but is still fully aware?³ These issues become even more complex if there is total locked-in syndrome, where eye movements are also absent. But families and healthcare providers must act with compassion and respect, as the patient’s mind is alive. 

Conclusion 

Patients with locked-in syndrome are living proof of how resilient the human mind is. Even when bogged down with one of the worst medical ailments, the identity, personality, thoughts and emotions remain intact. With compassion, technology and kindness, we can support these individuals, not just as patients, but as complete people with fully meaningful lives.