Locked-in Syndrome (LiS)
Locked-in Syndrome (LiS) results from a lesion to the brainstem, most frequently an ischemic pontine lesion. It results in severe impairments due to the complete disruption of the motor pathways controlling eyes, face, trunk and limb movements, including breathing, swallowing and phonation. However consciousness and cortical functions are preserved.
The American Congress of Rehabilitation Medicine (1995) defines LiS as a syndrome characterized by preserved awareness, relatively intact cognitive functions, and by the ability to communicate while being paralysed and voiceless.
Bauer described three categories of LIS (Bauer et al., 1979).
- Complete or total LIS: Quadriplegia and anarthria. No eye movement.
- Classic LIS: Preserved vertical eye movement and blinking.
- Incomplete LIS: Recovery of some voluntary movements in addition to eye movements
Early recognition of LIS state is important for rehabilitation. It is essential that LiS patients play an active role in decision-making processes regarding their rehabilitation. A reliable code to indicate yes and no usually constitutes the basis of communication. Initially many use eye movements and blinking to communicate. Because language skills are usually intact, many employ a system of spelling via an alphabetical code whereby the person with LIS indicates the desired letter by moving their eyes or blinking. (De Serres and Martel, 2008; Beukelman et al., 2007).
Early on, individuals with LIS need to be equipped with a means to indicate their needs or a desire to communicate. Should the patient regain control of a reliable movement, that could enable the activation of a switch enabling access to communication devices (eg computer with synthetic voice).
Initially, patients are essentially fed through a feeding tube. Following the initial assessment of their swallowing ability, most patients gradually start with eating smooth purees and thickened liquids. Tracheostomy, mechanical ventilation, cardiac failure, chronic obstructive pulmonary disease, uncontrolled emotional lability, improper positioning during feeding, undernutrition or dehydration are factors that may lead the healthcare team to remain cautious regarding feeding through the mouth.
To promote functional use of the patient’s emergent voluntary movements, it can be helpful to progressively move the patient into a more vertical position. Exercises to maintain range of motion, as well as breathing, eyes, head, trunk and limb control exercises are performed throughout the rehabilitation process. Stretching exercises, use of antispasmodic drugs or botulinum toxin injections help to decrease spasticity.
Prognosis (outlook for recovery)
According to the International Encyclopedia of Rehabilitation and researchers, recovery of horizontal eye movements prior to the first four weeks is associated with a good neurological prognosis (Bauer et al., 1979). Recovery of the oral-motor area (speech and swallowing) begins later and spreads over a longer period as does recovery of movement in distal parts of limbs of individuals (Janjua et al., 2005; De Serres and Martel, 2008).
The great majority of patients are weaned from their tracheostomy during the first months with one third able to utter isolated comprehensible words after the first year (Casanova et al., 2003). During inpatient rehabilitation, more than 50% of individuals start feeding orally and their gastrostomy is removed during the first year (Bruno et al., 2008; Beaudoin and De Serres, 2008; Casanova et al., 2003).
Level of independence is directly related to motor recovery. The majority of LiS patients can move around independently, most often in powered wheelchair. However very few reach a level of motor recovery enabling them to feed and perform activities of daily living on their own (Beaudoin and De Serres, 2008). Even after several years, spasticity often remains a significant problem for many. Of note, individuals with LIS usually do not suffer from a pain syndrome during the chronic phase.
Further Information and Support
Click here for the Australian Register for Disorders of Consciousness (ARDoC)
Click here for access to the blog of LiS individual, Tracey Gibb http://ridingwithlis.wordpress.com/
Coma Science Group
Families4Families – Acquired Brain Injury support network
Phone: 0433 388 250
National Institute of Neurological Disorders and Stroke
ReNew Neurobehavioural Services
Brain Injury Resource Center
Neural Signals Inc.
The mission of Neural Signals Inc. is to provide brain/computer communication systems for individuals with LiS.
Neural Signals have designed the LISKeyMicro - a tiny device that helps the totally paralyzed use a computer to communicate. www.LISKeyMicro.com
Reviewed by: Shannan Keen, MBMSc, Brain and Mind Research Institute, University of Sydney