Cognitive dysfunction syndrome, or CDS, describes an altered mental state of geriatric dogs and cats that resembles dementia in humans. According to Diane Frank, DVM, faculty of veterinary medicine at the University of Montreal, CDS in pets has four main characteristics: loss of recognition, loss of house training, disorientation, and changes in the sleep-wake cycle. There is no specific test for CDS, and many other disease processes can cause similar symptoms. The diagnosis of CDS is made by considering the age of the pet, confirming the presence of symptoms consistent with the syndrome, and by eliminating other medical conditions as causes for the cognitive changes.
Studies have found signs of cognitive impairment in 28% of dogs ages 11-12 and 68% of dogs 15-16, and in 28% of cats ages 11-14 and 50% of cats 15 and older. (See an overview of this research on the Ohio State University College of Veterinary Medicine website.)
Dog Dementia Symptoms
Frank notes that symptoms of dog dementia can result from encephalitis, tumors of the brain, and hypothyroidism, or they may be unexplained. To rule out these other causes of cognitive dysfunction, your veterinarian will perform various blood tests, and may require additional testing including spinal fluid analysis, radiographs and ultrasound. If a brain tumor is suspected, an MRI may also be ordered.
According to the the Ohio State University College of Veterinary Medicine, signs of dementia in dogs include:
- Disorientation – Has your pet suddenly “forgotten” how to climb the stairs? Does he get “lost” on walks or walk into corners that he could navigate well before?
- Interaction changes – Is your lap cat suddenly aloof, or has your independent dog become clingy?
- Sleep/wake cycle changes – Has your pet started pacing at night when he used to be a good sleeper? Does he sleep more during the day than he did before?
- House soiling – Is your cat missing the litter box or has your dog stopped letting you know when he needs to go out? Does it seem like he’s lost control of his bladder?
- Activity-level changes – Does your pet become upset when you leave or seem generally more anxious? Has his appetite decreased? Has he stopped loving his favorite toy, game or treat? Has he stopped grooming himself?
Cognitive Dysfunction Syndrome Symptoms in Cats
Older cats also suffer from cognitive dysfunction syndrome. According to Danielle Gunn-Moore, BVM&S and a specialist in feline medicine from the University of Edinburgh, cats with CDS show many of the same symptoms as dogs, but they are also likely to show increased night time vocalizations, decreased grooming activity, and declining interest in food. She also warns owners and veterinarians to consider the possibility of osteoarthritis in elderly cats who show symptoms of CDS. As Dr. Gunn-Moore explains, “The importance of arthritis should not be overlooked. Radiographic evidence of degenerative joint disease is present in 70 to 90 percent of cats over 10 years of age. Associated pain and/or dysfunction can result in reduced activity and mobility, aggression, altered interactions with the family and/or loss of litter box training.” These symptoms of arthritis in cats mimic the symptoms of CDS, but will improve with pain management in the case of osteoarthritis.
Cognitive Dysfunction Syndrome Diagnosis
Diagnosing cognitive dysfunction syndrome can be tricky. “There is no specific test for CDS,” says Karen Johnson, DVM, of Banfield Pet Hospital in Portland, OR. “The diagnosis is made based on age, symptoms and ruling out medical issues that can cause cognitive changes.”
Since CDS is a “diagnosis of exclusion,” your vet will test for a variety of other conditions to see if they can be ruled out. According to Dr. Johnson, tests would typically include basic blood work, a thyroid test, urinalysis, a neurologic exam and possibly x-rays or ultrasound.
“Some types of liver disease can cause changes that could mimic CDS, as could other types of brain disease, including cancer,” Dr. Johnson says. “Any illness has the potential to cause changes in mental status when normal physiologic parameters — blood pressure, electrolytes, etc. —
The tests can be expensive, but they’re worth it — they may identify a treatable condition. “The earlier a correct diagnosis is made and treated appropriately, the better the chance of being able to manage it,” says Dr. Johnson. “Also, it’s usually less expensive for the client and traumatic for everyone if a correct diagnosis can be made early.” If your vet ultimately diagnoses your pet with CDS, don’t despair: “The pet owner should understand that while treatment — medical
and environmental — doesn’t change the progression of disease, it can make a difference in quality of life for both the pet and family,” Dr. Johnson says.
Questions to Ask Your Vet if Your Pet Is Diagnosed with CDS
- Should I change my pet’s diet or give her any supplements?
- What medication might help, and what are its risks and benefits?
- What dose of the medication should I give my pet, and how often?
- How much does the medication cost?
- Do you recommend any games or exercise to increase my pet’s mental stimulation?
- How else should I adjust my lifestyle or routine to make things easier for my pet?
Cognitive Dysfunction Syndrome Treatment
Treatment for CDS in both dogs and cats includes a combination of environmental management and medical therapy. Selegine is a medication labeled for use in dogs to treat CDS. There is no medication labeled for use in cats to treat CDS, but the American Association of Feline Practitioners supports use of selegine as an off-label drug for treatment of CDS in cats. Environmental management of dogs with CDS should be aimed at simplifying access to food and water, and providing them with frequent access to sanctioned bathroom areas in order to reduce house soiling accidents. Cats might benefit more from having their living areas restricted to a smaller area – once they display symptoms of CDS they are less likely to tolerate changes in their environment and can feel more secure in smaller spaces.