[Yorkiemom1]

Originally Posted by Teresa Ford

As a trainer and lover of Yorkies, I always tell people before any retraining, or behavior modification we must know that a dog is healthy physically.
You said his behavior changed recently, you also said he didn't lift his head for treats, and barked like he was afraid or angry. Not lifting the head, snapping at invisible flies and startle reactions to sound, spinning in circles and fearful behavior may be symptoms of a brain issue. It could also be an eye, ear, or tooth problem. It may be all behavior. I can't tell, I can only make an educated guess. A good vet/ doctor who is trained to examine, and choose the right tests can come to a diagnosis and recommend a treatment plan. I just felt the need, to offer some suggestions that might help.

I agree....and it may take a trip to a specialist or vet school to get a good neurologist....