Yawning may be associated with an underlying disease.
Disorders that may be associated with excessive yawning:
(1) amyotrophic lateral sclerosis (ALS)
(2) stroke, including brain stem ischemia
(3) thermoregulatory dysfunction
(4) epilepsy
(5) withdrawal syndrome
(6) migraine
(7) brain tumors
Features of pathologic yawning:
(1) absence of excessive yawning prior to onset of disorder (although excessive yawning may be the first manifestation)
(2) no other explanation found
(3) yawning frequency parallels disease activity (decreases with control, increases with progression)