Cognitive dysfunction in aging cats is a common problem
Ryan Summerlin May 18, 2014
It is estimated that there are more than 82 millions cats in the United States. In the last 20 years there has been a 40 percent increase in cats older than 7 years of age and a 15 percent increase in those older than 10 years. More than 10 percent of cats are greater than 10 years of age. Clearly cats are living longer. As with humans, aging cats are increasingly impacted by age related problems like cognitive dysfunction, osteoarthritis, chronic kidney disease, systemic hypertension, reduced vision and hearing loss. At least 28 percent of cats 11-14 years of age develop at least 1 age-related behavior issue that reflects decline in mental functioning. By 15 years and older, 50 percent of cats exhibit behaviors like aimless wandering and vocalizations. These declines in mental functioning have been collectively referred to as cognitive dysfunction syndrome (CDS).
Signs of CDS include changes in behavior, inappropriate elimination, altered interaction with family, inappropriate vocalizations, and changes in sleep/wake cycles and activity. It is important to determine that these behavioral changes are not caused by other medical conditions. For example a cat with osteoarthritis may have inappropriate eliminations outside the litter box because they have difficulty stepping into a box with high sides. In addition, a cat with osteoarthritis may avoid interaction with family members because of discomfort. Dental problems can result in reduced appetite. Vision changes can be caused by systemic hypertension impacting on the retina. Uncontrolled diabetes can cause increased urine and often urination outside the litter box.
Since there are numerous medical problems that can appear like CDS, it is critical to have a complete evaluation by your veterinarian before deciding that your cat has age-related CDS. This evaluation will include a full history, complete physical examination including blood pressure measurements and mobility assessment, blood testing (including a complete blood count, chemistry profile and thyroid), and urine evaluation. These results can lead to a recommendation of further testing which may include X-rays, ultrasound, ECG, biopsies, or feline leukemia testing.
The causes of CDS in cats are not yet fully understood, but it is likely that a combination of factors leads to brain dysfunction. These factors include decreases in blood flow to the brain resulting from changes in the brain blood vessels, reduced output of blood from the heart, and altered blood viscosity. This diminished blood flow to the brain can cause lowered oxygenation of the brain and reduced delivery of nutritive substances and removal of cell metabolism products. Excess levels of free radical compounds can lead to cell damage. In addition, age-related loss of nerves and nerve connections in the brain can occur.
Cats with CDS can appear to be disoriented or confused; they can get trapped in corners or forget where their litter box is located.
Cats with CDS can appear to be disoriented or confused; they can get trapped in corners or forget where their litter box is located. Behavioral responses change; they can be more irritable, have increased anxiety, or have reduced responses to stimuli. There may be changes in sleep/awake cycles with a tendency to sleep during the day and be awake at night. They may vocalize inappropriately, especially loud crying at night. Many cats will aimlessly wander or pace. Eating patterns can change with either an increased or, more commonly, a decreased appetite. There may be a reduction in grooming. Memory loss may occur.
Although there are no published studies documenting effective therapy in cats, studies have been published in other species and form the basis for current recommendations. Treatment and supportive care include diet changes, environmental management, and possible drug treatments. Dietary changes are focused on supplying foods (vegetables and fruits) with increased levels of antioxidants to reduce damage caused by the free radicals. Increased levels of vitamins C and E, essential fatty acids, beta-carotene, and L-carnitine may be beneficial. Environmental enrichment can lead to an increase in cognitive function especially in conjunction with dietary changes. However, once cats have significant CDS signs, changing the environment may actually lead to increased stress and negative effects because these cats may be unable to adapt to these changes. A number of drugs have been used in cats including selegiline, buspirone and fluoxetine with varying success; however, studies in cats are lacking.
If you suspect your cat has CDS, contact your veterinarian for an evaluation to make sure there are no other age-related diseases that mimic CDS signs or are contributing to declining cognitive function. Since many older cats have multiple problems, a complete evaluation is essential for diagnosis and planning. Early supportive care for CDS appears to slow progress of dysfunction and helps to maintain quality of life.
Ron Carsten, DVM, PhD, CVA was one of the first veterinarians in Colorado to use the integrative approach, has lectured widely to veterinarians, and has been a pioneer in the therapeutic use of food concentrates to manage clinical problems. In addition to his Doctor of Veterinary Medicine, he holds a PhD in Cell and Molecular Biology and is a Certified Veterinary Acupuncturist. He practices integrative veterinary medicine in Glenwood Springs.