Yawning as a presenting symptom of Chiari malformation Type I: report of 2 cases.

Yawning is thought to be a behavior regulated by the brainstem. Although excessive yawning has been reported in brainstem strokes, demyelination, and tumors, the cases presented here are the first reports of excessive yawning in patients with Chiari malformation Type I (CM-I). The authors believe that brainstem compression at the craniocervical junction and ensuing edema were implicated in this curious symptomatology. They describe excessive yawning as a presenting feature of CM-I in 2 adolescent females. The presentation was acute in the first case and more chronic in the second. Both patients underwent foramen magnum decompression, which resulted in complete cessation of the excessive yawning.