Dear Vmt, I am a veterinarian at Kihei Veterinary Clinic. I do believe, based on the symptoms you stated, that you Boxer has a neurological disorder. Brain tumors are not highly unusual in dogs and other neurologic disorders can also occur. Another consideration would be hypoglycemia.This can cause transient loss of consciousness and signs that look like neurologic signs (seizures, muscle tremors) in some dogs. Checking the blood sugar levels several times will usually allow this problem to be diagnosed or ruled out. Liver disease sometimes causes this sort of behavior, as well. So it might be a good idea to check a serum chemistry panel the first time that blood sugar is evaluated since a panel would have both tests. High blood pressure can sometimes cause similar signs, too.These are the things that I can think of that might cause the signs that you are seeing. I think that it is worth looking into some of these problems, since there are treatments available for several of them. I do recommend checking in to a veterinary clinic A.S.A.P. If you have any other questions or concerns please do follow up with me. I wish you the best of luck! Jenni Li Helsen DVM - Kihei Veterinary Clinic (808) 879-5777 1476 S Kihei Rd Kihei, HI [email protected] www.kiheiveterinaryclinic.com