Dogs, just like humans, can have problems with learning, memory and attention, particularly as they get older. Several tests of cognitive ability in dogs have been used in research with a particular focus on the effects of ageing. What is less well understood is how diseases affect these cognitive abilities. In an article in CAB Reviews, Lena Provoost, Margret Casal and Carlo Siracusa discuss how changes in behaviour, such as loss of appetite, house soiling or changes in sleeping are often the first indicators to the pet’s owners that there is a problem. The team from the School of Veterinary Medicine at the University of Pennsylvania say that while those changes could be caused by mental decline, they could be secondary effects of other medical causes, such as pain from infection swellings or kidney disease.