Some years back my Emma Jean had "episodes" where she cried and walked the perimeter of rooms with her side touching the wall. If she attempted to eat, her mouth would miss the treat by a couple of inches. I could tell she wasn't quite there and was confused. She'd come out of it after 3 or 4 hours.

The regular vet and internist both said she didn't have a "post-seizure look". She was diabetic, but her blood sugar wasn't extremely high or low.

After all her other problems got the best of her, I asked about a necropsy, but the vet said it probably wouldn't provide any answers.

Back in 2008, I had to euthanize my 22 year old cat, Storm for much the same situation. He would walk along the walls for hours on end until he dropped from exhaustion. He'd cry the entire time. Vet couldn't find anything wrong with him and oddly enough, one pupil had 'blown' no longer round but instead one day it was rectangular and the episodes of wall walking began. It broke my heart because he and my youngest son had literally grown up together. My vet finally said Storm had alzhiemers and that was when we made the decision. Poor mister had no quality of life left. He didn't run into anything, just walked along and if something was in his way, he couldn't find his way out of nor around it and would lay and cry.

In follow up on this article, many thanks for your kind and thoughtful essay. Our cat was indeed FIV positive, but for years we wondered if it was a vaccine positive because her ear was tipped also.
She was estimated (after the fact by the neurologist on call) to be 6 years old.
I wanted to let you know she did have a 'pre-existing condition' ..FIV...that may have been a piece of the brain disease.
We have since adopted another FIV+ kitty, but we still miss our beautiful Sophia.

GOD Bless you, your family, and pets with good health and happiness. 3 years ago, Ashes was bitten by a opossum. He was taken to an Animal emergency where he got his shots for rabies, and stayed a few days to recover. He came home with a hole in the side of his right cheek which was later sutured shut. He got well soon, after he came back home, when I noticed a large lump underneath his chest. Thinking the lump was due to the effect of the bite and wasn't brought up by the Vet staff, I let it go. He had no discomfort from the lump. Around 2 and a half years later, Ashes started vomiting his food. He started sneezing. He would not stop sneezing and had a runny nose. He caught fever soon after and was sick. He started vomiting without eating and pacing to no ends crying all the time. I tried to keep him comfortable and hydrated, for he stopped eating. He only begged to go outside of the house, which I would not let. He would walk into the closet and try to get into tight places. Ashes started to get weaker and stopped getting into high places. He would not drink water or eat and was losing weight. He would not play. He wouldn't groom his coat. He would pace around and stumble over things and walk into his plate of food. He would jump in and out of his cat box for no good reason. I noticed one ear had lost hearing, and he was no longer able to judge distances. I took the time to think about his sickness. I told myself if Ashes was terminal. I would have to let him go. On 01-01-2013 I took Ashes to Eagle Rock Veterinary Hospital, where I waited to see if Ashes could just be a little sick or was terminal. The news came back badly. Ashes had gone blind and couldn't hear from the left part of his ear due to Brain Disease he had developed some how. The night before, I said my good bye to him all night. Naming his Mother and family cats. While I was already getting ready for us to part, I noticed the lump was no longer their. It must have been something Ashes contracted after the bite 3 years before and moved from one part of the body into his right part of the brain which was no longer curable. I was with him while he was on the Vet table. My heart beating fast and Ashes purring, he stopped purring and was pronounced deceased. While our last moments where very difficult for me, as my heart pounded out my chest with tears in my watery eyes', the only thing I thought about was holding him for the first time as a baby kitten. Naming him "Ashes 2 Ashes Dust 2 Dust" for good luck, and all the happiest and bad times we shared together which will last a lifetime. My last words to Ashes was "See you in 100 years Papa!"