I always thought if you took a song out of its element source and change it, it would be dementia. Taking a rock song and turn it polka, blue grass, does this.
Taking a country song into a metal song does this.
Taking an 80s song and change it to another genre doesn't seem to classify as dementia, I thought it was funny depending on who listened to it. The Buggles "Video Killed the Radio Star" is novelry and dementia but the PofUS cover isn't even though they rearrange the music.
Can't win them all