Typically cats do not have strokes but you can read about vascular accidents in the brain here
http://www.vetinfo.com/symptoms-cat-stroke.html
If your cat has a head tilt, her eyes look odd, if she walks like she is dizzy or is vomiting then this might be an inner ear issue called vestibular disease. You can read about this here
http://www.cathealth.com/vestibular.htm
This might also be a sign of a thyroid issue which you can read about here
http://www.vetmed.wsu.edu/clientED/hyperthyroidism.aspx
or may even be a sign of pain.
I'd plan on your vet checking your senior pet out for health issues to see what can be done to make her more comfortable.
Hope this helps you!
Cat Health, Behavior, Care Expert
30+ years cat owner, rescue, breeding, study of behavior & health care
She is a senior girl so the vet check up is your best option.
Hopefully they will find something treatable. So many health issues can show up at this age from thyroid to diabetes and more.
Some blood work and a physical may give you the best insight on what the problem is.
Its good you are alert to behavior changes as that is a plus when dealing with a senior pet.
Thanks for the above accept!