Canine cognitive disorder, also known as cognitive dysfunction, is a decline in the brain’s ability to function. Research suggest that signs of CDS occur in 23 percent of dogs 12 to 14 years old and in 41 percent of dogs older than 14 years.
Affected dogs develop amyloid plaques, a sticky buildup that accumulates on neurons in the front part of the brain, or frontal lobe. Among other things, the frontal lobe controls memory, learning, focus and sensory information. The plaques eventually spread to other areas of the brain, causing disorientation and lack of spatial awareness. Vision and hearing may also be affected.
While in many ways CDS is similar to Alzheimer’s disease in humans, it has some differences. One is that dogs do not appear to develop the neurofibrillary tangles that are seen in the brains of humans with Alzheimer’s disease.
Diagnosing Cognitive Dysfunction Syndrome
Cognitive Dysfunction Syndrome is a diagnosis of elimination. A veterinarian may diagnose cognitive decline if a physical exam and lab tests do not show the animal’s behaviors to have a medical cause, such as cancer, diabetes mellitus, hypertension, hypothyroidism, pain from osteoarthritis, or vision or hearing loss. Some behavioral problems can also mimic CDS. These include separation anxiety, aggression caused by pain, and poor housetraining.
To aid in diagnosis, and once other possibilities have been ruled-out, a more sensitive screening tool known as the DISHAA questionnaire should be used to assess cognitive function. Classic signs of CDS can be spelled out with the acronym DISHAA. The letters stand for Disorientation; alterations in Interactions with owners, other animals or the environment; disturbances in the Sleep cycle; increases in House soiling; changes in Activity; and an increase in Anxiety. Common signs reported by owners of senior pets are cognitive dysfunction such as “getting lost” in a corner, walking aimlessly or staring at walls; development of separation anxiety; other anxieties, fears and phobias; abnormal vocalization, such as howling late at night; destructive behavior; and house-soiling.
Behavioral support, environmental enrichment, medication, and nutritional and dietary therapy can all play a role in managing cognitive dysfunction and its clinical signs, but the condition is progressive and has no cure.
If you think your dog may have Canine Cognitive Dysfunction Syndrome contact your veterinarian.
 Salvin HE, McGreevy PD, Sachdev PS, & Valenzuela MJ. Under diagnosis of canine cognitive dysfunction: a cross-sectional survey of older companion dogs. Vet J. 2010; 184: 277–81.