Hello,
I am sorry your kitty is having trouble. I do not think that your kitty is experiencing problems with dementia, but rather has a urinary tract infection and or an illness that has predisposed him to a UTI. Cats are considered to be geriatric at 8 years old and can be prone to illness as they age. The 3 most common ailments known to afflict elderly cats are diabetes, kidney disease and hyperthyroidism. The symptoms include vomiting, diarrhea, increased water consumption, increased urination, dehydration, weakness, weight loss, muscle wasting, poor hair coat, changes in appetite, changes in behavior and increased vocalizations. Your kitty does not need to be showing all of the symptoms to have an illness, and since cats instinctively hide illness, it is not uncommon for a kitty to be healthy one day and pretty sick the next. I am concerned that your kitty may be diabetic, or that he may be experiencing some kidney insufficiency. The reason he is urinating out of the box is because he is uncomfortable, and he is associating that discomfort with the litter box. He is urinating out of the box in the hopes that it won't hurt as much. A UTI can be very serious, especially in a geriatric male kitty because the risk of urinary blockage is high. Urinary blockage is a life threatening complication, and is very painful. If at any point your kitty is unable to pass any urine, he needs to see a vet ASAP. Please see the following website for more information on urinary tract infections.
http://www.veterinarypartner.com/Content.plx?P=A&S=O&C=O&A=2457
Please see the following website for more information on urinary blockage.
http://www.veterinarypartner.com/Content.plx?P=A&S=O&C=O&A=1111
It would be best to have your kitty seen by his vet today, for an exam, urinalysis and some blood tests. He cannot wait too long to be seen as complications can arise quickly. Please let me know if I can be of further assistance. If this has been helpful, please hit the green accept button. Best of luck with your handsome man, I hope he feels better soon :)
Emergency Critical Care Nurse
16+ years of veterinary experience