Cognitive Dysfunction in Dogs and Cats

Laurie Anne Walden

Photo by Jessie Nelson on Unsplash

Cognitive dysfunction is fairly common in older dogs and cats. Similar to dementia and Alzheimer disease in people, cognitive dysfunction in dogs and cats is an age-related condition that affects the brain. The signs can be mistaken for normal aging changes and can overlap the signs of other common disorders. The earlier cognitive dysfunction is recognized, the earlier treatment can be started.
 
The causes of cognitive dysfunction aren’t fully known. Studies in dogs have shown some of the same neurological features, like β-amyloid accumulation and oxidative damage, that are found in people with Alzheimer disease. The only known (for now) risk factor in dogs and cats is age; animals with a diagnosis of cognitive dysfunction tend to be at least 8 years old. No particular breed or sex is known to have increased risk.
 
Signs
The signs of cognitive dysfunction are mostly behavioral. Over time, the behavior changes can affect the human-animal bond and become debilitating.

• Disorientation
• Anxiety
• Changes in social interactions: avoiding contact or seeking more contact than usual
• Changes in sleep-wake cycles: restlessness at night or sleeping more than usual during the day
• Loss of house training (dogs); urinating or defecating outside the litter box (cats)
• Loss of behavioral training
• Changes in activity level
• Changes in appetite

 
Other Possible Causes of the Signs
Lots of medical conditions that affect older animals cause the same signs as cognitive dysfunction and can also contribute to cognitive decline. Chronic pain from arthritis, dental disease, or other sources is very common in senior dogs and cats. Pain can lead to changes in interaction and activity levels, house soiling (because of mobility problems), and decreased food intake. Loss of vision, loss of hearing, metabolic diseases like kidney disease and thyroid disease, and neurologic diseases like brain tumors can also cause signs similar to those of cognitive dysfunction.
 
Diagnosis
No specific test for cognitive dysfunction is available, so the diagnosis is made by excluding other possible causes of the signs. The pet owner’s description of the behavioral changes is part of the diagnostic process, so behavior questionnaires and cognitive dysfunction rating scales are sometimes used. Many animals with cognitive dysfunction also have at least one of the other medical conditions that cause similar signs, which complicates diagnosis. Tests include thorough physical examination, blood tests, urinalysis, and possibly imaging studies of the chest, abdomen, and head (such as magnetic resonance imaging to look for brain lesions).
 
Treatment
Cognitive dysfunction can’t be cured, but early treatment can ease the symptoms and possibly slow the progression of the disease. Other disorders that contribute to the signs need to be addressed. Special diets and veterinary supplements (for example, antioxidants and omega-3 fatty acids) help some animals. Environmental enrichment can also improve the signs. Medications depend on the individual animal’s needs; selegiline is labeled for use in dogs (not cats) with cognitive dysfunction. Many animals with cognitive dysfunction also benefit from antianxiety medication.
 
Image source: https://unsplash.com/photos/a-small-white-dog-laying-on-top-of-a-couch-KCAlASmEbKY

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