A new, simple, and easy-to-understand explanation can be found in this video: http://myalzheimersstory.com/2017/05/30/is-it-alzheimer-dementia-neither-or-both-a-2-minute-animated-video-short-course/
...combines the expertise of three research groups at the University of Sheffield: Rehabilitation and Assistive Technology Group (RAT Group), the Centre for Assistive Technology and Connected Healthcare (CATCH) and the Telehealth and Care Technologies theme of CLAHRC YH (http://clahrc-yh.nihr.ac.uk/)