The 74-year-old singer has started penning his life story and documenting his incredible rise with his bandmates, including guitarist Pete Townshend, to becoming one of the biggest rock groups in the world.
However, Roger was been having difficulty getting the book written because his injuries have affected his ability to retain information.
Speaking to the Mail On Sunday newspaper, he said: ''The scariest thing about the memoir is that I have had four serious concussions in my life. There are huge gaps and I wonder why. But there is no wonder why.''
Roger admits the worst head injury he suffered was when he was knocked unconscious by a microphone stand being swung by disgraced glam rocker Gary Glitter during rehearsals for a performance of The Who's rock opera 'Quadrophenia' in London's Hyde Park in 1996.
The 'My Generation' hitmaker said: ''I broke my eye socket. I was out for 20 minutes. I did the show with a patch holding my eye in. That is a little bit concerning.''
Gary's involvement in the show came a year before the 'Hello, Hello, I'm Back Again' singer was arrested for possessing child pornography and subsequently jailed.