If your older dog fails to recognize you anymore and is spending his nights wandering the hallways, he likely has some form of canine dementia. Scientists estimate that there are more than 30 million geriatric dogs (over the age of 7) in the United States, and more than 15 million in Europe. The number of those elderly pooches suffering from cognitive dysfunction syndrome (CDS) is high: 28% of dogs 11 to 12 years old, and 68% of those that are 15 to 16 years old. The ailment seems to be progressive, and scientists know the earlier it’s detected, the better the chances for treatment. To improve the tests veterinarians use for rating the severity of the disease, scientists studied 215 dogs (including the three in the photo above) between 8 and 16.5 years of age that displayed some signs of CDS, they report in the current Applied Animal Behaviour Science. The researchers talked to the dogs’ owners about symptoms, including aimless walking and mindless staring, and observed the pooches’ responses to commands, and how they related to their owners, strangers, and other dogs. Their analysis showed the disease progresses rapidly, beginning with minor problems involving social behaviors and/or sleep. In 24% of the dogs, the ailment had changed from mild to moderate impairment within a short 6 months—five times faster than in humans, perhaps because of dogs’ shorter life spans, the scientists say. In later stages, the pooches lost their housetraining skills and were often confused about where they were. The new rating scale should help veterinarians diagnose even mild forms of CDS and may lead to drugs and other therapies that target specific stages of the disease in dogs, the scientists say.