First off, I'm not offering this up as another conspiracy theory - there have been diaries about some hidden medical condition, and I hadn't seen much evidence to support the hypothesis.
But, recently I have noticed the very distinctive lower jaw movement that Bush exhibits at the end of nearly every sentence. Watch him speak, once you notice it, it is hard to miss.
I know many have noticed this as well, based on a number of comments. But I disagree with most of these comments, which describe his "jaw clenching" or "grinding." I don't think he is grinding, which would be a tightening of his jaw muscles. If you notice, when his jaw moves, it does so from one side to the other with his mouth slightly open.
What he seems to be exhibiting is a more of either a "stereotyped/repetitive" motion or something called focal dystonia.
As for simple imvoluntary motions, there seem to be many causes, but one stands out in this case due to what must be a high level of stress: OCD.
It is very hard to understand OCD, but effectively some thought causes anxiety and subsequently a stereotyped (same thing each time) behavior relieves the anxiety. OCD is very complex, so this obviously goes beyond speculation. Here is a description from JHU.
Pharmacology could also be responsible. Amphetamines and stimulant drugs can produce tics -- however, it seems most likely to occur in those with a psycholological predisposition. I'm not suggesting Bush addicted to meth, but maybe under treatment for ADD or even a stimulating anti-depressant like Wellbutrin.
Dystonia, unlike a tic type movement, would most likely have an organic neurological origin. Most notably is early onset of Parkinsons. From Postgradmed.com:
Dystonia is a neurologic disorder characterized by involuntary movements that result in twisting, abnormal postures, and repetitive movements of a body part. The key factor that differentiates dystonia from other movement disorders is that there is a sustained abnormal posture that occurs at some time during the movement.
What stikes me about this description is the increasing leaning posture of Bush -- the way he leans to the side with force on the podium -- does not look natural. Additionally:
One clue to dystonia lies in the fact that dystonic movements often increase during activity, nervousness, and emotional stress, diminish during relaxation, and disappear completely during sleep.
Possible etiologies of adult onset dystonia inlcude:
- Demyelinating disease (eg, multiple sclerosis)
- Drug- or toxin-induced (eg, neuroleptic agents)
- Huntington's disease
- Parkinson's disease
Anyone with a medical degree or experience find these observations valid?