Evanescence's Terry Balsamo has opened up about his 2005 stroke and what he suspects caused the incident - headbanging.

The guitarist suffered a stroke that paralyzed the left side of his body in November 2005 and since that time has had to retrain himself on his guitar and undergo extensive physical therapy to regain use of his body.

Balsamo told Ultimate Guitar magazine, "I've always had a weird thing in my neck doing that, but I never would have thought it would have given me a stroke. [The doctors] actually saw the clot in my artery in my neck."

He added, "I still have paralysis in my left arm and hand. I'm like at enough where I can get by on tour. Basically this tour is like therapy right now for me. I'm hoping it will get better."

Evanescence are currently touring in support of their latest album, which reached number one on the Billboard charts last week.