Understanding Locked-In Syndrome: Causes and Care

Locked-In Syndrome

Rare neurological condition with severe motor impairment.

Incidence Rate

Affects 1 in 339,000 individuals.

Causes of LIS

estimated 80% caused by vascular events, particularly ischemic strokes, followed by TBI, also can be caused by tumours, infections and demylinating disorders

Core Features

• Quadriplegia - total paralysis of all limbs and torso

• dysphagia

• anarthria - complete loss of ability to articulate speech

• due to disruption of corticospinal and corticobulbar tracts as signals from brain can’t reach motor neurons in spinal cord and brainstem

Preserved features and functions

• cerebral cortex, reticular activating system, dorsal column pathway and spinothalamic tract

• Consciousness, awareness, hearing, touch, pain, and temperature remain.

Types of LIS

• Classic LIS

• Total Immobility LIS

• Incomplete LIS

Classic LIS

• caused by lesion in ventral pons, where nuclei and fibres of CN VI are

• horizontal eye movement is lost as it innervates lateral rectus muscles, which controls lateral movement

• can communicate by vertical eye movements or blinking

Total Immobility LIS

• Lesion in rostral or ventromedial midbrain

• CN III nuclei in medial midbrain and are damaged

• leads to ptosis and loss of vertical eye movement and blinking

• cannot communicate with eyes

• can only be diagnosed through EEG

Incomplete LIS

Presentation varies based on lesion location and extent.

• often misdiagnosed as vegetative state due to similarities, use MRI (most sensitive to detect lesions in brainstem) and CT scans to differentiate

AAC

Augmentative and Alternative Communication

• can be used to allow communicate and includes blinking to answer question, eye gaze tracking and communication boards

Brain Computer Interfaces (BCI)

Rely on neuronal activity

• use EEG output to measure brain activity and connect to external devices for communication

• useful where there is limited or no eye muscle fxn (e.g. total immobility LIS)

Stroke Awareness

Recognizing symptoms ensures timely medical intervention, and to ensure better quality of life with LiS

Interdisciplinary Team

Includes SLTs, physiotherapists, occupational therapists, psychologists and social workers and family.

Key Rehabilitation Goals

• optimise eye-gaze control

• AAC proficiency

• complication prevention

• functional particpation

• build autonomy

Quality of Life Metrics

Includes communication effectiveness, patient-reported outcome measures, patient wellbeing and family and social engagement.