Canine cognitive dysfunction syndrome (CDS) is a neurodegenerative condition in older dogs analogous to Alzheimer's disease, causing disorientation, sleep disruption, and behavioral changes that affect quality of life.
CDS causes progressive loss of the experiences that make a dog's life meaningful — recognition of familiar people, enjoyment of routine, restful sleep, and comfortable navigation of their environment. Disorientation causes anxiety and confusion; altered sleep patterns cause fatigue and restlessness at night. The condition is progressive and irreversible, though management can slow decline and improve quality of life. From a welfare perspective, regular quality-of-life assessment is essential as the disease advances — behavioral changes can be subtle, and owners often underestimate the extent of their dog's decline. Early diagnosis allows earlier intervention, and the parallel with human dementia makes this an ethically important area of comparative research.