What is canine cognitive dysfunction syndrome?

Canine cognitive dysfunction syndrome (CCDS) is a progressive neurobehavioral disorder that impacts senior pets and is often described as something like Alzheimer disease in humans, affecting both the patient’s daily functioning as well as the caregiver’s emotional well-being. Longevity is increasing due to improvements in nutrition, preventive medicine, and health care, meaning detailed awareness of this syndrome is increasing in importance.

During his lecture at the 2025 Hill’s Global Symposium, Christopher Pachel, DVM, DACVB, CABC, “Golden years, brighter minds: Innovations in Treating Canine Cognitive Dysfunction Syndrome,” explained more about the disease, including the risk factors and behavioral signs that these patients can start to show.

"As veterinary caregivers, we have a unique opportunity in that we're seeing these animals. We're seeing these clients on a recurring basis, and we have the opportunity to evaluate these dogs and look for some of the signs of aging and some of the signs that we recognize associated with canine cognitive dysfunction are not actually evident on a physical exam," Pachel explained to attendees.

"We might give this dog a clean bill of health, and it's only when we ask a few more questions and really sort of understand the full picture of that case that that's when we start to see other changes, things like hearing loss or vision loss or mobility issues, and when we start looking at some of the other patterns...that's when we really start to understand the case in its entirety. Truly, to understand the depth of these cases, we need to look beyond just what we can see within our physical exams," he continued.

Risk factors and behavioral signs

In canine patients aged 11 to 12 years, 28% of them exhibit one or more behavioral signs that are consistent with CCDS, and by age 15, prevalence increases to 68%.2 Factors that have been identified in association with this syndrome include age, body size, and activity level, with dogs showing signs of low physical activity being more likely to be diagnosed with CCDS; smaller breeds tend to have a later onset of CCDS compared with the larger ones. In research about CCDS, researchers noted that dogs aged 17 years with advanced CCDS often exhibit behavioral signs such as anxiety, restlessness, and altered human-dog interactions. Researchers also previously noted that it is possible for clients to initially treat these signs as normal aging, which could delay diagnosis and treatment.2

For the severity of the condition, there is a strong correlation found between the presence of periodontal disease and CCDS severity, as well as changes in olfaction and visual impairment.

According to Pachel, canine patients with CCDS may present with nighttime vocalization, increased activity at night, and fragmented sleep, which can also have a negative impact on the client, causing emotional strain and fatigue. One study conducted on the syndrome emphasized the caregiver burden as high for the cases of CCDS that involve disorientation, incontinence, and sleep disturbance. It also found that this can cause a delay in diagnosis because of the caregiver’s stress, which sometimes could result in premature euthanasia decisions.

A validated questionnaire is the cornerstone of CCDS screening in general practice. Researchers compared 3 cognitive screening instruments: the Canine Dementia Scale (CADES), Canine Cognitive Dysfunction Rating Scale, and the Canine Cognitive Assessment Scale, on 597 senior dogs. CADES was more sensitive for identifying dogs with mild to moderate cognitive impairment. Overall, all 3 questionnaires showed good correlation with each other.3

The DISHAAL mnemonic is widely used in clinical settings, but Pachel noted that it lacks formal validation. Despite that, its structured symptom framework has made it a practical tool for caregiver education and screening.

Each tool has its limits, such as recall bias, variability in the caregiver’s interpretation, and low specificity of CCDS. As a result, complementary diagnostics are being investigated.

Conclusion

When talking to veterinary professionals, owners will frequently ask whether behavior changes in their pet are something serious or normal aging, and some will even delay getting their pet's care due to fear of a terminal prognosis or uncertainty. Because of this, it is essential for veterinary teams to establish a strong foundation with clients by normalizing caregiver concerns, offering anticipatory guidance, and creating a safe space for them to discuss difficult decisions.

"[Guardians' perceptions of caring for a dog with canine cognitive dysfunction] looked at the caregiver burden that exists for individuals...and what they identified was that some of the clinical signs, like orientation, incontinence, disturbances, and sleep patterns had some of the greatest impact on those families. Not only did that have an impact on the day-to-day life and relationship and bond with those families, it also had an impact on some of the decision-making processes, as well as the timing for euthanasia, when that consideration of end-of-life care needed to be made," Pachel stated.2

CCDS significantly affects aging dogs and their loved ones. So, as dogs in your practice continue to age, the importance of CCDS continues to grow and challenge the veterinary profession. By continually evolving through diagnostic tools, therapeutic innovations, and caregiver support strategies, teams can help clients and patients through this difficult time in more ways than one.

References

1. Pachel C. Golden years, brighter minds: Innovations in treating canine cognitive dysfunction syndrome. Presented at: Hill’s Global Symposium; October 27-28, 2025; Phoenix, AZ.
2. Taylor TL, Smith BP, Hazel SJ. Guardians' perceptions of caring for a dog with canine cognitive dysfunction. Vet Rec. 2024;194(2):e3266. doi:10.1002/vetr.3266
3. Haake C, Lapham L, Kaye L, et al. Comparing standard screening questionnaires of canine behavior for assessment of cognitive dysfunction. Front Vet Sci. 2024;11:1374511. doi:10.3389/fvets.2024.1374511