I am sorry to hear about this behavioral change.
I am not sure the significance of this problem. It is difficult to assess that there is something medically wrong if you are not observing any other symptoms. However, for a 11 year old dog, I still have to be concerned about underlying diseases that may contribute to behavioral changes. This includes hypothyroidism
, cognitive dysfunction, and other endocrine related diseases.
I would recommend starting with a veterinary examination and having a basic blood test performed for an overall health assessment. Ensure that the blood test includes a thyroid check.
Since their are no other symptoms of illness, the blood is a good broad test that tells us a lot about the body.
Now, if at any time, you are noticing circling, head tilts, awkward eye
movements, or aggression, please notify your veterinarian immediately.
It would also be helpful if you can record the behavior
on a camcorder or cell phone video mode to show to your vet.
Please let me know if I can be of any further assistance.
Here is some information about cognitive dysfunction and hypothyroidism, although a may not be applicable to this situation.