He hasn't complained about the tingling since that one time. So, we guess his hand just fell asleep.

I got the radiology report today and one the impressions listed is new to him - "Nonspecific signal increase within the central tegmental tracts, possibly a normal anatomic variant."

The findings section elaborated a bit more saying "brain parenchyma is notable only for abnormally conspicuous signal increase within the central tegmental tracts...signal of the brain parenchyma is otherwise normal reflecting myelination to a mature endpoint since the March 2008 study. The hippocampi have slighly reduced volume bilaterally on a subjective basis but appear to have normal internal architecture and normal signal."

Any idea if this could relate to the yawning? Or otherwise warrant any follow-up?