The clip shown on NPR's website is part of a documentary called Alive Inside, which follows social worker Dan Cohen as he creates personalized iPod playlists for people in elder care facilities, hoping to reconnect them with the music they love. Cohen tells NPR's Melissa Block that the video of Henry is a great example of the link between music and memory.
"He is able to actually answer questions and speak about his youth, and this is sort of the magic of music that's familiar for those with dementia," Cohen says. "Even though Alzheimer's and various forms of dementia will ravage many parts of the brain, long-term memory of music from when one was young remains very often. So if you tap that, you really get that kind of awakening response. It's pretty exciting to see."
http://www.npr.org/2012/04/18/150891711/for-elders-with-dementia-music-sparks-great-awakenings