How to tell dog dementia from ordinary old age

The six behaviour domains

Veterinary assessment of cognitive change is organised around six domains, known by the initials DISHAA: disorientation, interactions, sleep-wake cycles, house-soiling and loss of learned habits, activity, and anxiety. They are categories of observation, not a scored test.

Grouping the signs this way is useful for one specific reason: it stops a single dramatic symptom from carrying the whole story. An owner arrives worried about night pacing, which sits in the sleep-wake domain, and only under questioning mentions that the dog now stands at the hinge side of doors, greets less, and has had three accidents indoors in a month. Those belong to three more domains, and together they describe something quite different from a dog who simply sleeps badly. The domains also make the opposite case visible. A dog with changes in one domain and nothing anywhere else is more likely to have a specific problem than a general cognitive decline, and that is a useful thing for a veterinarian to know before the examination starts.

What to write down for two weeks

Answer these five questions once a day, with the date and the time. They are the cognitive questions from our daily observation framework, each mapped to the domain it belongs to and the change that should send you to a vet without waiting for the fortnight to finish.

This is our own wording, built on the published domain structure rather than copied from any questionnaire, and it produces no score. Its entire value is that it turns “he has been odd lately” into dated observations a veterinarian can work with.

Why the diagnosis has to be made by exclusion

Canine cognitive dysfunction is a diagnosis of exclusion: it is reached after other causes have been investigated and ruled out. AAHA notes that similar behavioural signs may come from pain, organ dysfunction, or intracranial disease — three categories that are found by examination and testing, not by observation.

The practical stakes are high. A dog pacing at night because arthritic hips will not let them settle needs pain management, and a website that hands the owner a dementia label instead has cost that dog months of comfort. The same is true in reverse for a dog whose confusion has a metabolic cause that bloodwork would find. This is why every path on this page ends at an appointment rather than at a result, and why the fortnight of notes matters more than any score: the notes help the exclusions happen faster, which is the only part of the process an owner can speed up.

If stiffness or reluctance on stairs is part of the picture, read the arthritis and mobility page before you settle on a cognitive explanation. And if the question underneath all of this is about quality of life, score the published scale and take the result to your vet rather than deciding alone.

What this page will not do

Each fact below arrives with a restriction written by the people who compiled it, and those restrictions are printed here rather than paraphrased. They are the reason this page stops where it does.

• Do not use prevalence to diagnose an individual dog.
• Do not copy a proprietary questionnaire or claim a diagnostic score.
• Never label dementia from a web checklist.
• No diagnostic output.

Method and sources

Senior-dog dataset version 2026.09, compiled 2026-09-07. The prevalence figure, the six domains, the alternative causes and the diagnosis-of-exclusion rule all come from the AAHA page below. Nothing on this page is a diagnosis, and no number here was estimated.

• AAHA Cognitive Dysfunction & Behavioral Anxiety — primary, checked 2026-09-07. Quoted directly on this site.
• Cornell Canine Cognitive Dysfunction — primary, checked 2026-09-07. Quoted directly on this site.

Where the rest of our data comes from and how we write and correct these pages.

Common questions

Can dogs get dementia?

Yes. Age-related cognitive impairment is described in AAHA's 2023 senior care guidelines, which cite literature reporting it in roughly 14 to 22.5 percent of dogs over eight years old. The veterinary name is canine cognitive dysfunction. It is a real, recognised condition rather than an owner's impression, and it is diagnosed by a veterinarian after other causes have been ruled out.

What are the first signs of dementia in dogs?

The signs are grouped into six behaviour domains: disorientation, changed interactions with people and other pets, disrupted sleep-wake cycles, house-soiling or loss of learned habits, changed activity levels, and anxiety. Owners most often notice the night ones first, because pacing at 3am is hard to ignore, while a slightly shorter greeting at the door is easy to miss.

Is my dog's night pacing definitely dementia?

No, and this is the most important caveat on the page. AAHA notes that similar behavioural signs may come from pain, organ dysfunction, or intracranial disease. A dog that cannot get comfortable because of arthritis and a dog that is disoriented at night can look identical from the sofa. Only an examination separates them, and the treatable causes are worth ruling out first.

How do vets diagnose canine cognitive dysfunction?

By exclusion. AAHA describes canine cognitive dysfunction as a diagnosis of exclusion, meaning the other explanations for the behaviour are investigated and ruled out before the label is applied. That is why no online checklist, including anything on this site, can give you the diagnosis: the work is in what gets excluded, not in what gets ticked.

What should I write down before the appointment?

Dates, times and specifics. When the behaviour started, whether it is worse at particular hours, how often it happens in a week, and what else changed at the same time, including any new medication or a change in the household. A vet can do a great deal with two weeks of dated notes and very little with the phrase "he's been odd lately".

Does dementia mean it is time to put my dog down?

No. Advanced age alone is not an adequate criterion for end-of-life decision making, and neither is a behavioural label on its own. What matters is the dog's comfort, function and the balance of good days against bad ones, considered with a veterinarian who knows the case. Our quality-of-life page walks through a published scale for exactly that conversation.