Dementia affects 17–25 million people worldwide, with an estimated four million in the US and an estimated 800,000 people in the UK [Ritchie, 1995; Keefover, 1996]. It affects predominantly elderly people, and as population growth increases in this age range, the numbers affected by dementia are expected to rise significantly. The prevalence of dementia in people over the age of 65 is 5% and in people over 80, it is 20%. It has been estimated that 26% of women and 21% of men over the age of 85 have some form of dementia, of whom approximately 50% have Alzheimer’s disease (AD) [Melzer, 1997].