Hi David, I thought you might find this study interesting:
Sleep Med. 2010 Mar;11(3):329-30. Epub 2010 Feb 16.
Yawning, sleep, and symptom relief in patients with multiple sclerosis.
Gallup AC, Gallup GG Jr, Feo C.
Department of Biological Sciences, Binghamton University, Binghamton, NY 13902, USA. firstname.lastname@example.org
Patients with multiple sclerosis (MS) suffer from thermoregulatory dysfunction, and repetitive yawning and sleep problems are symptoms of MS. Because yawning and sleep are involved in thermoregulation, we investigated the association between yawning, sleep, and symptom relief in patients with MS.
Sixty patients filled out a questionnaire about how often they yawned, whether yawning provided relief of MS symptoms, and how sleep affected these symptoms.
Results showed that over one in three patients reported that their MS symptoms improved following a yawn, and of those experiencing relief, nearly half reported that it lasted for several minutes or longer. Not getting a good night's sleep often made MS symptoms worse, while napping during the day provided symptom relief.
This is the first study showing that yawning provides symptom relief in patients with multiple sclerosis.
Copyright 2010 Elsevier B.V. All rights reserved.http://www.ncbi.nlm.nih.gov/pubmed/20163983