The oldest member of my pack was suffering from advanced dementia. I hope you don't see this in your dogs, but you should learn to recognize when your reliable pooch is suffering from this. I have not experienced a close acquaintance with Alzheimer's before, but after watching this disease progress in my dog I now understand why this is so horrifying in people. Symptom #1 was weight lost which becomes atrophy. I think that once the brain damage gets to a point it interferes with appetite and possibly nutrition regulation. My dog was pretty lean, and never gained appreciable weight even after neutering. Starting with a healthy weight I could begin to see his ribs. As this progressed it became muscular atrophy. This becomes most apparent in the face when the large jaw muscles around the temples waste away changing the appearance of the dog. It's interesting when you consider a person with dementia that is having trouble caring for themselves. Shirt half tucked in, hair not combed, disconnected gaze. My dog looked exactly like that - like President Biden without a wardrobe and style detail. The dog won't eat enough to keep on the weight, there is just a reduced interest in food. Symptom #2 is lethargy. As the disease progresses the dog becomes lethargic. I think part of this is fatigue from losing weight, and part of it is brain disease. Your dog won't come when you call, even for feeding which is usually the high point of the day. Reflecting on this I think that many times the functional parts of his brain just were not working. At this point you'll see ups and downs. My dog appeared rather sick with a cough and after a week pulled through that. Some days he was becoming chipper again and appeared to be recovering. Then there would be an episode of extreme lethargy. I think these episodes were where the brain just disconnected for a while. This part was disturbing because I was hopeful he was pulling through, and then he'd lethargic again and not respond to anything. I think that is week long cough may have been loss of autonomic swallow reflex. Months to a year ago he started having to cough after taking a drink - I think that this may have been the early sign. He'd take a drink and then strongly cough a couple times to clear water that went down the wrong pipe. Symptom #3 is declining motor skills. He had trouble walking and trouble with balancing standing up. I think the balance was bad enough that the dog preferred to stand and teeter rather than sitting or laying because of the balance required to sit or lay down. When he would be up and walking it was without purpose. He didn't seem to have a plan to walk anywhere - just kind of aimless shuffling. The small step out the door became difficult for him to navigate. There were not any indications of pain - more like he just needed to go slow and pay great attention to get through the door. He started falling down with increasing frequency. Symptom #4 is "getting stuck." When the dementia is advanced the dog will walk into a corner and just glitch out. He couldn't navigate his way away from the corner - so he would just stand there. The first time he did this I lost him (small dog) on the patio. He slid behind a garbage can and the wall and didn't know how to get out. I think when you get to this point the disease is very advanced. For me the hardest part was hoping for a rebound. You'd see good days, good moments, but they get farther apart and shorter duration. In the end I had him euthanized and by that time I don't think he even recognized me. It was a sad day yesterday - he was a good boi. Farewell brown dog! I will say this - I miss him and it is a relief, but the dog I miss hasn't been around for a month or more. You have to know when it is time to say goodbye. I don't have to worry about fishing him from the bottom of the pool any more, I don't have to watch him fall down or not recognize what were the most important things to him. He was middle aged when I adopted him, and he had a good run. I still have two more - and you know, I may adopt another.