Your Senior Dog Patient Might Have Dementia. Here Is How to Actually Diagnose It.

A landmark new working group just published the first standardized diagnostic guidelines for canine cognitive dysfunction syndrome. Here is what they say, what they mean for your practice, and why it matters more than you might think. Adapted from the CCDS Working Group guidelines, Journal of the American Veterinary Medical Association, 2026. 

If you have been in practice for any length of time, you have had this conversation. An owner comes in with a 12-year-old dog. The dog is pacing at night, getting stuck in corners, staring at walls, occasionally not recognizing people it has lived with for a decade. The owner asks if this is normal. You suspect cognitive dysfunction. You do not have a clean diagnostic framework to point to. You manage it as best you can, rule out what you can rule out, and move on.

That is about to change.

A newly published international working group has produced the first consensus-based diagnostic guidelines for canine cognitive dysfunction syndrome (CCDS) — a condition that has been increasing in clinical frequency as dogs live longer but has, until now, lacked standardized criteria for diagnosis, staging, or monitoring. The guidelines, published in the Journal of the American Veterinary Medical Association, are designed for both researchers and the primary care veterinarians actually seeing these patients. That second part matters.

What Is CCDS, Actually

The working group defines CCDS as a chronic, progressive, age-associated neurodegenerative syndrome characterized by changes in cognitive function that are severe enough to affect daily life. The key phrase there is 'severe enough to affect daily life.' This is not the same as normal aging. This is pathological cognitive decline, and the distinction matters both for treatment decisions and for managing owner expectations.

The syndrome is captured by the acronym DISHAA, which covers the six behavioral domains affected: disorientation, impaired social interactions, sleep disturbances, house soiling along with learning and memory deficits, activity changes that can go either direction, and increased anxiety and fear. Dogs do not need to be showing changes in all six domains for a diagnosis — early disease often presents with changes in just one or two, and the research suggests nighttime restlessness, decreased daytime activity, and changes in social interaction tend to appear first.

The working group also makes an important conceptual move: they recommend treating CCDS as an umbrella term for canine dementia, acknowledging that amyloid and tau-associated pathology are recognized but that other neurodegenerative processes have not yet been fully explored. In other words, the picture is probably more complicated than we currently know, and the guidelines are built to accommodate that uncertainty rather than paper over it. 

Why This Matters

CCDS has genuine parallels with Alzheimer's disease in humans, including amyloid plaque deposition in the cortex and hippocampus. Dogs may be among the best naturally occurring models for early-stage Alzheimer's research that exists. What you are diagnosing in your senior patient has real translational significance.

Three Severity Stages

The guidelines propose three stages that are deliberately framed around what owners observe rather than what pathology reveals, which makes them practically useful in the exam room.

Mild CCDS means behavioral changes are subtle, infrequent, or low severity. The dog is generally functioning normally. Owners frequently attribute what they are seeing to old age and may not mention it unless specifically asked. If you are not screening for it, you are probably missing it at this stage.

Moderate CCDS means behavioral changes are more frequent and severe, starting to interfere with normal daily activities and requiring management adjustments. The sleep disruption category is particularly impactful here because disturbed sleep carries significant caregiver burden and is often what finally motivates an owner to seek help.

Severe CCDS means overt, debilitating changes. The dog needs support even for basic functions and requires comprehensive management. Quality of life decisions often enter the conversation at this stage.

The New Diagnostic Framework: Two Levels of Certainty

This is the part that changes how you work up these patients.

Level 1 diagnosis is based on three things: a consistent history of slowly progressive DISHAA signs confirmed by an abnormal CCDS questionnaire score, physical and neurologic examination that identifies and manages comorbidities, and persistence of signs after those comorbidities have been addressed. The neurologic examination should not show focal or lateralized signs. CCDS causes diffuse forebrain dysfunction, not focal deficits. If you are seeing head tilt, unilateral circling, cranial nerve deficits, or new-onset seizures, you need to be imaging before you land on a CCDS diagnosis. The minimum database should include a CBC, chemistry panel, urinalysis, and blood pressure.

Level 2 diagnosis adds brain MRI showing cortical atrophy, specifically an interthalamic adhesion height below 5mm, plus cerebrospinal fluid analysis within normal limits. MRI at this stage serves two purposes: ruling out alternate diagnoses and confirming the cerebral atrophy that is the most significant imaging finding in CCDS. The guidelines note that ITA to cranial height ratio is more meaningful than raw measurement because it controls for body size and breed variation. They also recommend including susceptibility-weighted sequences when imaging senior dogs because vascular microbleeds are increasingly recognized in this population and their relationship to CCDS is still being worked out.

Definitive postmortem diagnosis requires histopathological confirmation of cortical atrophy, amyloid deposition, myelin loss, neuroinflammation, and amyloid angiopathy. For most clinicians this is academic rather than practical, but understanding the pathology underpinning the clinical picture is useful context.

SCREENING RECOMMENDATION:  The working group recommends annual behavioral screening starting at age 7 using a short senior health form. From age 10 onward, a full CCDS questionnaire every 6 months is recommended for all dogs regardless of presenting signs. The DISHAA questionnaire is the recommended tool for primary care because of its widespread adoption and its coverage of all six behavioral domains.

The Questionnaire Question

Caregiver questionnaires are valuable for detecting and monitoring CCDS, but the guidelines are clear on something that often gets blurred in practice: they are not stand-alone diagnostic tools. A score does not make a diagnosis. What matters more than any single score is tracking changes in that score over time for an individual patient, ideally completed by the same caregiver at each visit.

The working group recommends the DISHAA questionnaire for clinical use. Other validated tools include the Canine Dementia Scale (CADES) and the Canine Cognitive Dysfunction Rating scale (CCDR). The research comparing them is interesting: CADES is more sensitive to mild changes, while CCDR is less susceptible to placebo effect and more stable over time. Both have been used in clinical trials. But DISHAA is what primary care veterinarians are actually using, and it is the only questionnaire that addresses all six DISHAA domains including anxiety, sleep, and activity.

One practical note: every question needs to be interpreted against that dog's individual baseline. House soiling is only a meaningful clinical sign of CCDS if the dog was previously fully housetrained.

What About Biomarkers

The honest answer is: not yet, but the field is moving.

Neurofilament light chain can be measured in plasma using ultrasensitive techniques and has been shown to increase with age and disease status in dogs. It is a nonspecific marker of neuronal injury rather than a CCDS-specific diagnostic test, but monitoring plasma NfL concentrations over time could offer a practical way to track neurodegeneration longitudinally. More data are needed on how body weight, kidney disease, and other neurological conditions affect NfL before it is clinically usable.

Amyloid beta 40 and 42 concentrations and ratios potentially offer greater diagnostic specificity, though concentrations are elevated in dogs with epilepsy and reference ranges have not been established. Reliable tests for canine phosphorylated tau are still lacking.

Blood biomarkers for CCDS are the next major frontier in this field. The working group identifies them as a priority, and when they arrive they will significantly improve both diagnostic accuracy and therapeutic monitoring. For now, clinical diagnosis based on history, examination, questionnaire scoring, and imaging where indicated is where the practice is.

Blood biomarkers for CCDS are the next major frontier. When they arrive, they will change how we diagnose and monitor this disease. Right now, clinical diagnosis is where the practice is.

The Bottom Line for Your Practice

CCDS is underdiagnosed because it is easy to miss at the stage when it matters most, and until now there has been no clean framework to work from. The new guidelines give you that framework.

Start behavioral screening at age 7. Use the DISHAA questionnaire from age 10 onward as part of routine senior wellness. When a senior patient presents with progressive behavioral changes across the DISHAA domains, rule out comorbidities first, then establish a Level 1 diagnosis through history, examination, and questionnaire. Consider imaging when the neurologic examination is abnormal or when you need to rule out other intracranial disease before committing to a CCDS diagnosis.

And have the honest conversation with owners early. The caregivers who are describing nighttime pacing, daytime disorientation, and a dog that sometimes does not seem to recognize them are often relieved to know that what they are seeing has a name, a framework, and a management approach. The absence of a cure does not mean the absence of a diagnosis.

This is dementia in dogs. We can do better than chalking it up to old age.

ABOUT THE RESEARCH

This article is adapted from the CCDS Working Group consensus guidelines published in the Journal of the American Veterinary Medical Association (JAVMA), Volume 264, Issue 4, 2026. The working group was supported by a grant from the American Kennel Club Canine Health Foundation. The full paper, including the DISHAA questionnaire and diagnostic flowchart, is available at avmajournals.avma.org.