It's rare and that probably explains why so few dog owners have heard of it.
Canine hyperkinesis is a condition which renders a dog almost untrainable.
Over at DogTips.co they've published an insightful profile of the condition and also a really interesting piece detailing a case study of using drugs as a meant to try treat hyperkinesis in a dog.
Well worth a couple of minutes of your time.
What is Hyperkinesis in Dogs?

