Becoming forgetful as you get older may mean your brain is deteriorating, even if you do not have a disease like Alzheimer's.

Experts found patients who had not been diagnosed with cognitive impairment or Alzheimer's, but still had memory problems, have less tissue in the area of their brain that handles memory.

By looking at MRI results, researchers found patients who passed memory tests, but are still forgetful, had a three percent reduction in gray matter in part of their brains.

Doctors say if patients complain of memory problems but pass memory tests, they still may have a deteriorating brain. That means treatment should begin immediately.