Why is it difficult to diagnose Alzheimer's disease early?

Alzheimer's disease usually is not diagnosed in the early stages, even in people who visit their primary care doctors with memory complaints. One reason is that people and their families generally underreport the symptoms. They may confuse them with normal signs of aging. The symptoms may emerge so gradually that the person affected doesn't recognize them. Or the person may be aware of some symptoms but go to great lengths to conceal them.

Despite decades of research, there is still no definitive test to diagnose Alzheimer’s disease. Talking with the person and a family member or friend who can corroborate the person’s memory loss is the first step to determine if physical and cognitive changes are part of the normal aging process or if they are indicative of mild cognitive impairment and Alzheimer's disease.

Eliminating other possible causes of memory loss is also important in diagnosing this disease. Depression is a common disease that occurs with age and someone with severe depression can appear to have Alzheimer’s. Parkinson’s disease also shares common symptoms. The list goes on, and even sleep medications and analgesics taken for the aches and pains of aging can make us forgetful.