SEATTLE — Researchers at the University of Washington and Colorado State University examined brain tissue from 24 dogs with canine cognitive dysfunction and found abnormal protein clumps in regions also affected by Alzheimer’s disease in people. The study, described by UW Medicine on Oct. 12, is an effort to map the brain changes associated with cognitive decline in dogs. Researchers also collected blood from about half of the dogs, with their owners’ permission. “No one had mapped this neuropathology in dogs before,” said co-author Dr. Caitlin Latimer, an associate professor of laboratory medicine and pathology at the UW School of Medicine. Comparing behavior in aging dogs and people had suggested similarities, she said, but examining and measuring changes in the brain offered a more direct picture of the disease. Latimer said she was struck by the extent of plaque in some of the dogs. The findings raise the possibility that dogs could help researchers study early Alzheimer’s, though the study does not establish that the conditions are identical or that the findings will lead to a treatment. Dogs may offer a distinct research model because they develop cognitive dysfunction naturally and share many aspects of human environments, including air and water. Mice, by contrast, do not naturally develop the same neurodegenerative disease, UW Medicine said. Canine cognitive dysfunction can involve changes in an older dog’s behavior and mental abilities. The researchers’ brain-tissue findings add evidence of a biological overlap with human dementia, while further research will be needed to clarify how useful that overlap is for understanding Alzheimer’s in people.