Older dogs face the prospect of senile dementia (senility) just as do humans. The glucose utilization rate of the cerebral cortex drops by almost half between youth and old age. Interestingly, dogs and rats are the only non-primates known in old age to develop neuritic plaques in their brains that resemble those of humans with Alzheimer's disease.viii

Brain cell apoptosis (genetically programmed cell death) could account for dementia in aged dogs and suggested that aged dogs may be useful as a simplified animal model for Alzheimer's disease in man.ix While aging dogs do suffer from strokes, the incidence rate is far less than in humans. Sleep disorders in old age are not uncommon, nor are behavioral changes such as development of separation anxiety, increased vocalization, and shyness.

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