Prior to their triumphant return to metal with the great album Book of Souls, Iron Maiden’s lead singer Bruce Dickinson found out that he had throat cancer. Battling through that, he recorded the album Book of Souls and then got treated for the effects that he received from contracting HPV orally. On that double CD, he recorded a song for Robin Williams, who had just lost his battle to the effects he was feeling from being diagnosed with Parkinson’s disease. This song, “Tears of a Clown,” is an amazing tune, and it’s one of the shorter songs on an album full of extended guitar and vocal assault epics.
One of the key differences is ESSENTIAL TREMOR (Lyme) vs. RESTING TREMOR (Parkinson's).