Locked-in Syndrome

Anatomy

Bilateral ventral pons

Vascular

Basilar artery

Signs & Symptoms

Side Manifestation Comments
Both Weakness – upper and lower extremity Quadriplegia: bilateral cortical spinal tracts
Both Weakness – face – entire side Bilateral corticobulbar tracts
Neither Lateral gaze weakness Bilateral fascicles of CN VI
Neither Dysarthria Bilateral corticobulbar tracts

Notes

Bilateral ventral pons lesions (iscemic or hemorrhagic) may result in this deefferented state, with preserved consciousness and sensation, but paralysis of all movements except vertical gaze and eyelid opening.

  1. Quadriplegia due to bilateral corticospinal tract involvement
  2. Aphonia due to corticobulbar tract involvement to lower cranial nerve nuclei
  3. Occasionally, impairment of horizontal eye movements due to bilateral involvement of the fasciclesof cranial nerve
  4. Reticular formation is spared, so the patient is typically fully awake. The supranuclear ocular motor pathways lie dorsally, so that vertical eye movements and blinking are intact.