Gaping, or involuntary opening of the mouth, may occur as a focal dystonia of the motor trigeminal nerve, also known as Brueghel syndrome after that artist’s painting De Gaper ("Yawning man", ca. 1558) which is said to illustrate a typical case. Afflicted individuals may also
demonstrate paroxysmal hyperpnea and upbeating nystagmus, suggesting a brainstem (possibly pontine) localization of pathology. The condition should be distinguished from other cranial dystonias with blepharospasm (Meige syndrome).
Gilbert GJ. Brueghel syndrome: its distinction from Meige syndrome.
Neurology 1996; 46: 1767-1769