The Pump It Up singer, 62, appears in a public service announcement on behalf of Music & Memory, a charity which provides elderly people suffering from Alzheimer's disease and other types of dementia with music players loaded with personalised playlists aimed at triggering lost memories.

"You may take a music device like this for granted," he says in a YouTube video promoting the non-profit organisation. "But for millions of people with Alzheimer's and dementia, a personal music player loaded with their favourite songs can reconnect them to an entire world.

Praising the charity he adds, "Music & Memory is helping people with Alzheimer's and dementia unlock memories and rediscover the soundtrack to their lives."

Dementia is a personal cause for the singer, real name Declan Patrick MACManus, as he saw both his grandmother, Molly, and father, the trumpet player Ross MACManus, suffer from different forms of dementia.

Elvis' 1989 hit Veronica, a song he co-wrote with The Beatles' Paul MCCartney was about his grandmother's battle with Alzheimer's.

When his father started exhibiting symptoms of Parkinson's disease related dementia six years ago, Elvis insisted his dad was near an iPad playing his favourite music at all times.

"At times when little else penetrated his torments and distress, it was music rather than spoken word that reached him," Elvis tells Rolling Stone magazine.

"On a few occasions, he emerged through an apparent fog to state the identity of a singer or gather a tune in a voice that was still surprisingly melodious and true at a time when his speech was reduced to a hoarse whisper."

Ross passed away in 2011, but his son's insistence on playing him music meant his final moments were accompanied by the music he loved.

"In the end, his passing was accompanied by a recording of his favorite song by his favorite trumpet player, Clifford Brown, an incredible piece of chance and mercy that would stretch credulity if written in a fiction," Elvis explains.

Other musicians to back the Music & Memory initiative include Carole King and Kenny Chesney.