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Locked in – A prisoner in your own body

Locked-in syndrome is a paralysis of the entire body, all the way up to the facial muscles, most often caused by an infarction in the brainstem. Sufferers’ movement is limited to the area around the eyes, although they are fully conscious and able to hear and see normally. Through intensive rehabilitation, it is possible to improve their quality of life dramatically.  

“Locked in” is a very fitting description. Despite remaining completely conscious, sufferers are fully paralysed, meaning they are unable to communicate using speech, facial expressions or gestures. They can no longer use their facial or tongue muscles. Even their swallowing and gag reflexes stop working. Damage caused in the area of the so-called pons, which is what causes the syndrome, means that only vertical eye movement and blinking remain possible. They provide the only means of communication between the patient and their environment.

Causes of locked-in syndrome

The brainstem, which this disorder affects, is the oldest part of the brain in evolutionary terms. It is the lowest section of the brain and consists of ascending and descending nerve fibres and clusters of neurons/somata. Morphologically it consists of the midbrain, the pons and the medulla oblongata. The brainstem connects and processes incoming sensory impressions and outgoing motor signals. In addition, it is responsible for elementary and reflex control mechanisms. The brainstem is also where the nuclei of cranial nerves II-XII are found. From here, the head, neck, chest and abdominal organs are supplied with nerves and the heart, circulatory and respiratory functions regulated. The brainstem is also where support and righting reflexes are coordinated – these are necessary for maintaining an upright posture, for example.  

Cerebral infarction is the more common form of stroke. Only patients who suffer a stroke in the brainstem can develop locked-in syndrome as a result. The disorder affects the part of the brainstem which is important for motor functions. Alertness and sensitivity continue to function in people with locked-in syndrome. In addition to cerebral infarction and intracranial haemorrhaging, there are also less common causes of locked-in syndrome, such as traumatic brain injury, encephalitis caused by tick bites, amyotrophic lateral sclerosis, multiple sclerosis and tumours. Other neurological causes can also trigger locked-in syndrome. These include bilateral, cross-sectional damage to the corticobulbar and corticospinal tracts in the bridge region. The disorder can also be caused by a failure of the corticospinal and corticobulbar pathways and by the division of the reticular formation and the cranial nerve nuclei.

Locked-in syndrome vs. vegetative state – easily confused 

One important issue in clinical practice, however, is that the symptoms associated with locked-in syndrome mean that it is easily confused with a person being in a comatose state. This is shown by the following hard-hitting video about a patient who was thought to be in a persistent vegetative state – and treated as such – for 23 years. http://tv.doccheck.com/de/movie/734/locked-in-mangelnde-diagnose (in German)

A persistent vegetative state results from serious injury to the cerebrum, which is most often caused by head trauma or a lack of oxygen to the brain. These patients may appear to be awake, but their consciousness is no longer intact. It is not possible for them to make contact with or perceive the outside world. In such cases, after a certain period of observation the patient is described as being in a persistent vegetative state. But with locked-in syndrome, the cerebrum, i.e. the patient’s consciousness, is not affected. Even so, the cerebrum loses all ability to control the body, which is why this condition is externally very similar to that of patients in a persistent vegetative state. Patients with locked-in syndrome are often not recognised as such, and are forced to hold out in a motionless body despite being perfectly alert.  

Rehabilitation – Communicating by imagination

Treatment of locked-in syndrome is very versatile and includes physiotherapy, occupational therapy and speech therapy. The sooner treatment begins, the better the rehabilitation results that can be achieved. In some cases this means that amazing improvements are possible, because the brain apparently has better repair mechanisms than was previously thought. In parallel to physical therapy, occupational therapy attempts to compensate for neurophysiological deficits. The aim of speech therapy is to improve the patient’s ability to communicate. At the beginning, patients are usually only able to communicate by moving their eyes to create agreed signals. Speech therapy exercises are indeed challenging, but in the long term they can enable the sufferer to make contact with the outside world once more. In order to communicate, sufferers may also be able to use brain-computer interfaces. A highly complicated process teaches the patient to control a computer using certain thoughts. The person can use electrical brain activity to give the computer signals, and in turn the computer converts these thoughts into control commands. Research into further methods is ongoing.    

Letter board according to Büttinghaus, as used in early communication. The line digits are read first, followed by the line letters after a signal.  

Locked-in syndrome is generally very rare and usually attracts only little attention. However, the question does arise as to whether there really are so few patients with this disorder, or perhaps we simply do not always realise when patients are suffering from it, with too many diagnoses of a persistent vegetative state instead of locked-in syndrome. It is therefore important to examine each patient with the relevant symptoms more closely in order to rule out the possibility of locked-in syndrome and to treat the patient accordingly. 

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