Cognitive Dysfunction Syndrome in Dogs

This condition, once called the senile or old dog syndrome, is a newly recognized disease, somewhat similar to Alzheimer's disease in people. In dogs with cognitive dysfunction syndrome (CDS), the brain undergoes a series of changes that result in a decline in the mental faculties associated with thinking, recognition, memory, and learned behaviour. Fifty percent of dogs over age 10 will exhibit one or more symptoms of cognitive dysfunction syndrome. Cognitive dysfunction is a progressive disease with increasing signs of senile behaviour.

Disorientation is one of the principal symptoms of cognitive dysfunction syndrome. The dog appears lost in the house or yard, gets stuck in corners or under or behind furniture, has difficulty finding the door (stands at the hinge side or goes to the wrong door), doesn't recognize familiar people, and fails to respond to verbal cues or his name. Hearing and vision loss must be ruled out.

Activity and sleep patterns are disturbed. The dog sleeps more in a 24-hour period, but sleeps less during the night. There is a decrease in purposeful activity and an increase in aimless wandering and pacing. Dogs with cognitive dysfunction may also exhibit compulsive behaviours with circling, tremors, stiffness, and weakness.

Housetraining is another area that suffers. The dog may urinate and/or defecate indoors, sometimes even in the view of his owners, and may signal less often to go outside. Incontinence, however, is a physical problem and has nothing to do with CDS.

Often, interactions with family members become much less intense. The dog seeks less attention, often walks away when being petted, shows less enthusiasm when greeted, and may no longer greet his family. Other dogs seem to need human contact 24 hours a day.

Some of these symptoms may be due to age-related physical changes and not to cognitive dysfunction. A medical condition such as cancer, infection, organ failure, or drug side effects could be the sole cause of the behavioural changes or could be aggravating the problem. Thus, medical problems must be tested for and eliminated before senile symptoms are attributed to CDS.

There is no specific test for CDS. The number of symptoms the dog exhibits and the severity of the senile behaviour are important considerations in making the diagnosis.

As CDS cannot be cured, preventive measures should be taken and symptoms alleviated. Older dogs should still be given the opportunity to lead an active and varied life. From the age of 7 or 8 years it is advisable to switch to a specially formulated senior dog food which is rich in antioxidants.

The drug Anipryl® (selegiline), used by humans to treat Parkinson's disease, has been found to improve symptoms and the quality of life for many dogs with cognitive dysfunction syndrome. The drug can be prescribed by your veterinarian after a diagnosis of CDS has been determined.