Thanks to advances in medicine, both humans and their animal companions are living longer. But, there’s a possible tradeoff. Longer lives may be touched by steep declines in brain function.
Like humans, brain mass in four-legged pets shrinks with age. Cells contributing to healthy brain function (white matter) die off while unhealthy (glial) cells propagate. The chemicals that regulate brain and body function and the pathways that carry them degenerate and fail. Antioxidant activity decreases, no longer offsetting the production of toxic free radicals. Sadly, the sum of these changes spells cognitive decline.
Cognitive Dysfunction Syndrome (CDS) is a neurobehavioral disorder affecting older dogs and cats. CDS is marked by an age-related decline in cognitive skills that affect functioning and behavior changes that are not linked to other medical conditions (e.g. a urinary tract infection).
The first signs of CDS are usually observed by family and are eerily similar to those Aunt Minnie or Grandpa Joe displayed at that holiday party. Dogs or cats may become easily confused or disoriented, circle or wander aimlessly, pace, and stare. They may be less inclined to play, fail to recognize family members or beg for food in the presence of a full bowl. Day sleeping is increased along with nocturnal waking at unusual hours. Trained behaviors such as toileting fall away leading to indoor soiling.
Pet parents and even some veterinarians often mistake symptoms of CDS for normal aging. It is vital, therefore, for pets to get a formal workup beginning with a targeted questionnaire for pet parents regarding their pet’s behavior.
A thorough medical evaluation should include physical, neurological and orthopedic exams as well as blood panels, urinalysis and imaging (as needed) to rule out disease as the source. The Canine Dementia Scales is a statistically validated, highly sensitive rating scale for canine CDS. The scale contains 17 unique items, distributed across four relevant domains: (1) spatial orientation, (2) social interactions, (3) sleep–wake cycles, and (4) house soiling.
Madaria A, Farbakova J, Katina S, et al. (2015) found that mild cognitive impairment often manifested as abnormal social interaction, moderate cognitive impairment correlated with the above plus disrupted sleep-wake cycles; animals with severe cognitive impairment displayed deficits across all four domains.
The incidence of CDS appears to increase with age. Neilson JC, Hart BL, Cliff KD, Ruehl WW (2001) found CDS in 28 percent of dogs aged 11-12, leaping to 68 percent in dogs aged 15-16 years. Thirty-six percent of cats aged 11-21 developed CDS; half of cats 15 and older showed behavioral changes.
How to counter the effects of CDS:
Manage and enrich the environment: Increase daytime exercise to reduce nighttime wakefulness. Keep routines consistent and home pathways clear to ease stress. Consider additional litter boxes for cats and, where possible, a sanitary patio relief area for dogs. Modify traditional body commands for dogs in pain (e.g. “look” instead of “sit” or “down.”).
Enhance Nutrition: Diets rich in antioxidants, mitochondrial cofactors, phosphatidylserine, and omega-3 fatty acids have proven to reduce the harmful effects of toxic free radicals. Check out Dr. Karen Becker’s article on diet, supplements and activities for CDS. A diet overhaul combined with gentle, cognitive retraining may improve a pet’s function and mood.
Pharmacology: Selegiline hydrochloride (Anipryl; zoetis.com) is approved for the control of clinical signs associated with canine CDS. This drug selectively inhibits an enzyme that destroys neurotransmitters vital to health. When appropriate, anti-anxiety medications can improve well being; beware of potential drug interactions.
New research shines another ray of hope for animals with CDS. A 2022 study of more than 15,000 dogs by The Dog Aging Project showed that exercise can prevent dementia or slow its progress by reducing inflammation and increasing brain plasticity. Perhaps cats can also benefit from indoor exercise.
Our animal companions deserve nothing less than a happy and dignified twilight of life. A holistic approach where family and professionals are equally engaged gives them the best chance.