S-adenosylmethionine (SAMe) and cognitive dysfunction in dogs (Sponsored by Virbac Animal Health)
Disease Background: Cognitive dysfunction syndrome
Let's begin by defining age-related cognitive dysfunction in dogs. In North America, we use the term cognitive dysfunction syndrome to describe a spectrum of clinical signs that relate to perception of stimuli and to memory and learning. The clinical signs, which can start months or years before owners become aware of them, are primarily caused by age-related changes in the brain.It is important that practitioners identify the clinical signs. Several studies have looked at the frequency of cognitive dysfunction in dogs. In one, researchers found that at least 68% of dogs 15 to 16 years old had one or more clinical sign of cognitive dysfunction.1 Twenty-eight percent of dogs aged 11 or 12 years also had at least one sign.
The diagnosis of cognitive dysfunction is a diagnosis of exclusion. Practitioners must remember two things. First, in aging pets, medical problems can contribute to many of the same clinical signs of cognitive dysfunction so you have to rule out medical causes. Second, even if you find medical causes, the dog can still have concurrent cognitive dysfunction.
Landsberg: Now let's talk about the clinical signs associated with cognitive dysfunction. In North America, we often use the acronym DISHA, which stands for disorientation, interaction changes with family members and other pets, sleep-wake cycle alterations, housetraining loss, and activity level changes (both increase in repetitive activities or decreased overall activity). What are the most common signs associated with early cognitive dysfunction?
Dr. Amanda Florsheim: Dogs are usually presented to me because of housesoiling or a disturbance in their sleep-wake cycle. These signs disrupt owners' lives, so they are what general practitioners see.
Florsheim: At my clinic, we are implementing a standard questionnaire for dogs older than eight years. This form asks questions about these subtle signs, such as: Have you seen a decrease in play? Does your dog seem to sleep more during the day? We ask about subtle signs early, rather than waiting for the more dramatic signs to appear later.
Dr. Valerie Dramard: As the disease progresses, disorientation becomes another sign of cognitive dysfunction. The dog gets lost in the garden or in its neighborhood. Or when you open the door to let it outside, the dog is on the wrong side, standing next to the hinges. That is quite bizarre to owners.
Landsberg: If a dog is brought in for housesoiling or night waking, how would you determine it has cognitive dysfunction, as opposed to some other problem?
Several years ago, I was on a panel of the American Animal Hospital Association that set up senior care guidelines. Those guidelines recommend annual examinations at middle age and twice-a-year examinations as pets reach their senior years. This is the time to take a good behavioral history. It is critical to talk with the owners at every year's checkup—these are the pet's caregivers.