• Stimulus evoked oral automatisms (chewing and sucking) were observed in three cases of the locked-in syndrome. Oral and perioral regions were the most sensitive for elicitation of these motor patterns, but other regions were also susceptible. The most probable explanation is loss of pyramidal control over the bulbar system of mastication.
Gerhard Bauer, Monika Prugger, Eric Rumpl. Stimulus Evoked Oral Automatisms in the Locked-in Syndrome. Arch Neurol. 1982;39(7):435–436. doi:10.1001/archneur.1982.00510190053017