Methods for measuring atrophy in a brain region occupied by the hippocampus and entorhinal cortex. In one example, MRI scans and a computational formula are used to measure the medial-temporal lobe region of the brain over a time interval. This region contains the hippocampus and the entorhinal cortex, structures allied with learning and memory. Each year this region of the brain shrank in people who developed memory problems up to six years after their first MRI scan. The method is also applicable for measuring the progression rate of atrophy in the region in an instance where the onset of Alzheimers disease has already been established.