Several models have been developed that describe the progressive worsening of symptoms and the loss of function of Alzheimer's disease. One of the most commonly used is the Global Deterioration Scale (GDS) developed by B Reisberg and colleagues. It is used to answer some of the most frequently asked questions from caregivers and patients with Alzheimer's disease; " How long have we got?" and "What stage of the disease is he/she in?".
The GDS gives, in seven stages, a guide to understanding...

