Does your senior dog sometimes seem lost in their own home? Do they get stuck in front of furniture, stare at a wall, pace at night, sleep all day, vocalize without apparent reason, or suddenly start having accidents indoors after being house-trained for years?

Many owners attribute these changes to old age. However, it's not always just a simple consequence of aging.

Canine Cognitive Dysfunction Syndrome (CCDS) is a neurodegenerative disease affecting older dogs. It shares some mechanisms with human Alzheimer's disease, although it is not strictly identical. Today, this condition is well-documented, relatively common, and still largely underdiagnosed.

The earlier the diagnosis, the more effective the support options.

What Science Establishes

Canine Cognitive Dysfunction Syndrome (CCDS) corresponds to a progressive deterioration of brain functions related to aging.

Affected dogs may show changes in orientation, social interactions, sleep, house-training, activity, or emotional behavior. These various aspects are regularly described in major veterinary journals dedicated to brain aging.

One of the most striking observations concerns the underdiagnosis of this condition.

In the study by Salvin and collaborators published in 2010, approximately 14% of older dogs showed signs consistent with cognitive impairment, while fewer than 2% had received a veterinary diagnosis.

More recent work supports this: cognitive impairments increase with age and often go unnoticed in their early stages.

However, figures vary depending on the screening tools used. The study by Haake and collaborators published in 2024 notably shows that some questionnaires seem more sensitive than others for detecting mild or moderate forms.

Biological Mechanisms

CCDS is often compared to Alzheimer's disease because several brain lesions are similar.

In some older dogs, β-amyloid deposits, progressive cognitive decline, and age-related cerebral vascular changes are observed.

These similarities explain why dogs are sometimes used as models for studying human brain aging.

However, caution is needed with the shortcut "doggy Alzheimer's."

The brain of an aged dog does not exactly replicate the human disease. Some major lesions observed in humans, particularly accumulations of tau protein, are not found in the same way in dogs.

The parallel helps to better understand the disease, but CCDS should not be considered a copy of human Alzheimer's.

With the progression of lesions, the dog may gradually experience difficulties with memory, learning, orientation, or adapting to their environment. These changes often appear slowly, which explains why they are sometimes attributed to normal aging.

What This Means in Practice: The DISHAA Acronym

Clinical signs are often grouped under the acronym DISHAA.

D — Disorientation

The dog seems lost in familiar places, gets stuck behind furniture, hesitates in the house, or stares at surfaces for no apparent reason.

I — Interactions Modified

They respond less to loved ones, seek less contact or, conversely, become abnormally dependent.

S — Sleep Disturbed

The sleep-wake cycle changes: nocturnal restlessness, vocalizations at night, or drowsiness during the day.

H — House-training Loss

Urinary or fecal accidents appear, despite the dog having been house-trained, after other medical causes have been ruled out.

A — Activity Modified

Spontaneous activity decreases, or aimless restlessness appears.

A — Anxiety

The dog may become more anxious, worried, seek proximity more, or vocalize without an identifiable cause.

What is often misunderstood

"It's normal, he's just getting old."

Aging alone does not explain significant disorientation, loss of house-training, or a sustained reversal of the sleep-wake cycle.

These signs should lead to a consultation rather than being trivialized.

"He's being difficult at night."

Nocturnal restlessness is one of the classic signs of CCDS.

It is generally linked to a disruption of biological rhythms, disorientation, or difficulty managing the environment.

"There's no point in treating an old dog."

Even if there is no curative treatment, several approaches can improve the quality of life for the dog and their family.

The goal is not to make the disease disappear, but to slow its progression and preserve daily functioning.

"There are no tests."

There is no single test to diagnose CCDS.

However, several standardized questionnaires are available, including CCDR, CADES, and CCAS, and their use is gradually developing in geriatric veterinary medicine.

For which dog and at what stage?

CCDS primarily affects older dogs.

Age remains the main risk factor. Large breeds, whose biological aging is generally faster, may sometimes show earlier signs.

We can distinguish three main stages.

Early stage

Some subtle changes appear: slightly disturbed sleep, minor disorientation, or a moderate decrease in interactions.

Moderate stage

Several areas of DISHAA are affected, and the impact on daily life becomes visible.

Advanced stage

Disorientation becomes significant, sleep disturbances worsen, house-training deteriorates, and anxiety can become pronounced.

The main challenge remains early detection, as it is at this stage that support options are most beneficial.

When to consult and what therapeutic options are actually documented?

A consultation is recommended as soon as the first signs of DISHAA appear in an older dog.

The diagnosis of CCDS remains a diagnosis of exclusion. Chronic pain, certain hormonal diseases, metabolic disorders, sensory impairments, or certain neurological diseases must be ruled out before concluding a cognitive impairment.

Selegiline

Selegiline is currently the only drug approved in the United States for the treatment of CCDS.

The study by Campbell and collaborators, conducted in 641 dogs, reported clinical improvement in a majority of treated animals.

It should be noted, however, that this was an open-label study without a control group, which limits the level of evidence.

Diet and non-pharmacological approaches

Certain enriched diets, specific supplements, and environmental modifications show encouraging results.

Taylor and collaborators' review published in 2023 particularly highlights the benefit of approaches combining environmental enrichment and adapted nutrition, while noting that studies remain very heterogeneous.

Exercise and cognitive enrichment

Regular physical activity and cognitive activities are often recommended.

Recent large cohorts observe an association between more active dogs and a lower frequency of cognitive signs. However, these studies cannot yet confirm that an exercise program directly slows the progression of the disease.

The primary goal remains to maintain the dog's abilities, preserve their sense of familiarity, and improve their quality of life.

Sources

1. Haake J et al. Comparing standard screening questionnaires of canine behavior for assessment of cognitive dysfunction. 2024.
2. Salvin HE et al. Under diagnosis of canine cognitive dysfunction: a cross-sectional survey of older companion dogs. 2010.
3. Landsberg G et al. Cognitive dysfunction syndrome: a disease of canine and feline brain aging. 2012.
4. Campbell S et al. A noncomparative open-label study evaluating the effect of selegiline hydrochloride in a clinical setting. 2001.
5. Vikartovska Z et al. Novel diagnostic tools for identifying cognitive impairment in dogs: behavior, biomarkers, and pathology. 2020.
6. Dewey CW et al. Canine cognitive dysfunction: pathophysiology, diagnosis, and treatment. 2019.
7. Taylor TL et al. Non-pharmacological interventions for the treatment of canine cognitive dysfunction: a scoping review. 2023.
8. González-Martínez A, Miró J. Canine Cognitive Dysfunction and Alzheimer's Disease—Two Facets of the Same Disease? 2019.