The prevalence (number of cases of a disease based on the population at the time) of Intellectual Disability (ID), formerly known as Mental Retardation, is estimated between 1 and 2.5% and the incidence (number of new cases per year) is estimated to be around 1.8%.

Recent data indicates a reduction in the prevalence of ID only in western populations, while the opposite trend is evident among people with low to middle range incomes.

From November 8, 2010 to February 28, 2011, a training course for volunteers of Intellectual Disability (ID) will take place for the V.A.I.P.E.D.D. project, Voluntary Service and Augmentative Interaction with Parents and Experts on Developmental Delay, sponsored by the Center for Research and Development of AMG of the Misericordia of Florence in collaboration with CESCVOT (Center for Volunteer Service in Tuscany).