Brain aging in dogs: parallels with human brain aging and Alzheimer's disease.

Differentiating normal from pathologic aging is a challenge to veterinarians treating geriatric patients and to clinicians diagnosing Alzheimer's disease. Part of the difficulty stems from the lack of a biological marker. Dogs and humans develop similar cognitive dysfunction with age, and a subset of individuals develop severe impairments. Similar neuropathology also develops in the brains of elderly humans, individuals with Alzheimer's disease, and dogs. Both species develop senile plaque neuropathology, with more extensive plaque accumulation associated with severe cognitive impairments. This article discusses similarities in the clinical features and development of neuropathology with age in both dogs and humans and provides a discussion of treatment options.