Here is a number that surprises most owners: among dogs aged 11–12, roughly 28% show at least one sign of cognitive decline, rising to about 68% of dogs aged 15–16 [1]. Yet fewer than 2% are ever formally diagnosed [2]. Canine cognitive dysfunction — often called dog dementia — is one of the most common conditions of old age, and one of the most missed, because its early signs are quiet and easy to write off as "just getting old."
That gap matters, because although CCD can't be cured, it can be slowed — and the earlier you act, the more good years you protect. This guide explains what to watch for, how vets frame it, and which interventions actually have evidence behind them.
What canine cognitive dysfunction is
CCD is a progressive, age-related decline in the brain, with changes strikingly similar to Alzheimer's disease in people — including the build-up of beta-amyloid plaques and oxidative damage to brain cells [3]. It is a real, physical disease of the ageing brain, not a behaviour problem and not simply "slowing down." Cats get an equivalent condition (feline cognitive dysfunction), and much of this guide applies to them too.
Because it's gradual, the shift is easy to miss month to month. Owners often only recognise it looking back — "actually, she's been pacing at night for a while now."
The signs: the DISHAA checklist
Vets use a simple framework — DISHAA — to catch the pattern. Recognising two or more of these categories in a senior dog is a reason to book a check-up [4]:
- D — Disorientation. Getting "stuck" behind furniture or on the wrong side of a door, staring at walls, seeming lost in familiar rooms, not recognising familiar people.
- I — Interaction changes. Less interest in greeting you, being petted or playing; sometimes new clinginess or irritability.
- S — Sleep–wake changes. The classic one: sleeping more by day and becoming restless, pacing or vocalising at night — sometimes called "sundowning."
- H — House-soiling. Toileting indoors again after years of being reliable, or forgetting to signal to go out.
- A — Activity changes. Aimless pacing or wandering, repetitive behaviours, or the opposite — reduced exploration and apathy.
- A — Anxiety. New or increased anxiety, restlessness, or fear of situations they used to take in their stride.
None of these is proof of dementia on its own — which is exactly why the next step matters.
First, rule out the things that mimic it
Many treatable conditions look like cognitive decline. Pain from arthritis can cause night restlessness and irritability. Failing sight or hearing can look like disorientation. Kidney or liver disease, diabetes, Cushing's disease and urinary infections can all cause house-soiling or drinking-and-waking at night. High blood pressure and thyroid disease affect behaviour too.
This is why CCD is a diagnosis of exclusion: your vet will examine your dog and often run bloodwork and a urine test to rule out medical causes before attributing the changes to the brain [4]. Catching a treatable problem here is the best possible outcome — and even when it is CCD, treating co-existing pain or disease usually improves things noticeably. (This is the same logic behind why early screening saves pets: in seniors, the story is rarely one single problem.)
What actually helps — the evidence
CCD is managed, not cured, and the best results come from combining several approaches early [3][4].
Diet and nutrition. This is one of the few areas with clinical-trial support. Diets enriched with antioxidants and medium-chain triglycerides (MCTs) — an alternative brain fuel — have been shown to improve signs of cognitive decline in older dogs in controlled studies [5]. Omega-3 fatty acids (DHA/EPA) and specific supplements (e.g. those containing SAMe or a blend of antioxidants) are also used; ask your vet which have evidence rather than marketing behind them.
Mental and physical enrichment. "Use it or lose it" holds for the ageing dog brain. Regular gentle exercise, food-puzzle toys, short training games and novel but manageable experiences are associated with slower decline [3][4]. Keep sessions short and successful.
Medication. Selegiline (l-deprenyl) is licensed in many countries for CCD and helps a proportion of dogs [4]. For the anxiety and night-time restlessness that make CCD so hard to live with, vets may add anti-anxiety medication or melatonin. These are prescription decisions for your vet.
Environment and routine. Predictability is calming for a confused dog. Keep furniture, feeding times and walk routes consistent; add night-lights; use non-slip runners; block off hazards like stairs and pools; and keep water easy to find. Reintroduce toileting cues patiently rather than punishing accidents — the dog isn't being disobedient.
What to expect over time
CCD is progressive, so the goal is to slow it and keep quality of life high, not to reverse it. Many dogs live comfortably for a long time with the right combination of diet, enrichment, medication and a dementia-friendly home — especially when it's caught early. Keeping a simple diary of signs (how many bad nights this week, any new behaviours) helps you and your vet see whether a change is working, and supports honest, compassionate decisions later on.
The bottom line
Confusion, night-time restlessness and "accidents" in an old dog are not something to accept in silence as inevitable ageing — they're a signal. Because CCD shares so many signs with treatable conditions, the single most useful thing you can do is get a senior dog with two or more DISHAA changes properly checked. From there, an early, combined plan — the right diet, enrichment, a dementia-friendly routine and, where appropriate, medication — is what protects the good years still ahead.
Frequently asked questions
What are the first signs of dementia in dogs? Often the earliest change is the sleep–wake cycle — a dog that sleeps more in the day and becomes restless, paces or vocalises at night ("sundowning") — along with subtle disorientation, such as getting stuck in corners or seeming briefly lost in a familiar room [4]. Reduced interest in greeting or playing, and toileting accidents after years of being clean, are also early flags. Two or more DISHAA changes warrant a vet visit.
How is dog dementia diagnosed? There's no single test; it's a diagnosis of exclusion. Your vet assesses the behavioural pattern (often using the DISHAA tool) and rules out conditions that mimic it — pain, kidney or liver disease, diabetes, Cushing's, thyroid disease, high blood pressure, and sight or hearing loss — usually with an exam, bloodwork and urinalysis [4].
Can canine cognitive dysfunction be treated or slowed? It can't be cured, but it can be slowed, especially when caught early. The best-supported steps are a diet enriched with antioxidants and medium-chain triglycerides, ongoing mental and physical enrichment, a consistent dementia-friendly routine, and — where appropriate — medication such as selegiline plus anti-anxiety support [3][4][5].
My old dog is confused and restless at night — what can I do tonight? Make the environment predictable and safe: night-lights, non-slip runners, blocked stairs and pools, easy-to-find water, and a calm, consistent bedtime routine. Then book a vet check promptly, because treatable pain or disease is a common driver of night restlessness in seniors and is very worth ruling out.
Is dog dementia painful? CCD itself isn't thought to be painful, but the anxiety and disorientation are distressing, and many affected dogs also have painful conditions like arthritis that worsen the picture. Treating pain and anxiety often improves both comfort and the cognitive signs.
Track the changes with Stay
Stay helps you log your senior dog's behaviour and screening over time, flags when age-appropriate check-ups are due, and turns "he seems a bit off" into a clear picture you can share with your vet — so subtle decline is caught early, when management does the most. AI assists; experts decide. Join the Stay waitlist.
Important note
This article is decision-support information, not veterinary advice. It does not diagnose your individual pet. If your senior dog is showing behaviour or toileting changes, see your veterinarian — several treatable conditions look like dementia.
References
- Neilson JC, Hart BL, Cliff KD, Ruehl WW. Prevalence of behavioral changes associated with age-related cognitive impairment in dogs. J Am Vet Med Assoc. 2001;218(11):1787–1791.
- Salvin HE, McGreevy PD, Sachdev PS, Valenzuela MJ. Under diagnosis of canine cognitive dysfunction: a cross-sectional survey of older companion dogs. Vet J. 2010;184(3):277–281.
- Landsberg GM, Nichol J, Araujo JA. Cognitive dysfunction syndrome: a disease of canine and feline brain aging. Vet Clin North Am Small Anim Pract. 2012;42(4):749–768.
- American Animal Hospital Association. Senior Care Guidelines / DISHAA cognitive assessment tool. https://www.aaha.org/aaha-guidelines/
- Pan Y, et al. Dietary supplementation with medium-chain TAGs and cognitive function in aged dogs. Br J Nutr. 2010;103(12):1746–1754.