Locked-in Syndrome

Excerpt

Locked-in syndrome (LIS) is a complex medical condition presenting with quadriplegia, bulbar palsy, and whole-body sensory loss due to damage in the brain stem, most commonly the anterior pons. Cognition, vertical eye movement, blinking, and hearing are classically preserved in patients suffering from the condition. The diagnosis of the locked-in syndrome is often challenging due to its similarity with conditions such as akinetic mutism and coma. It may take weeks to diagnose, and family members at the bedside are usually the first to notice the decreased motor functions of the patient.

Locked-in syndrome has three main types. The classical form is defined by total immobility, with the preservation of the ability to perform vertical eye movements, blink, and maintain a normal level of consciousness. The incomplete form is defined as the classical form with small additional motor functions. The total immobility form is defined as a complete body paralysis, and loss of eye movement with the preservation of cortical function examined via EEG. In the classical and incomplete forms, consciousness is often evaluated by blink-response or eye movement-response to questions. An EEG may be used in patients in the complete form to assess brain activity, sleep-wake cycles, and attention.

In the acute setting, CT or MRI of the brain helps characterize the causative agent to establish a treatment earlier. Physical examinations analyzing motor function, sensation, and reflexes are often reassessed to rule out other potential conditions and estimate the rate of recovery in patients. Due to the rare nature of this condition, recovery and management have been a topic of debate. Still, an increasing amount of literature has demonstrated efficacy in traditional supportive management and rehabilitation.