Instagram/Tom Dumont & Gwen Stefani Music No Doubt guitarist Tom Dumont reveals early onset Parkinson's diagnosis ahead of the band's Las Vegas Sphere residency. Hear his heartfelt message. April 13, 2026 AceShowbiz - Tom Dumont, the longtime guitarist for No Doubt, has publicly revealed that he has been diagnosed with early onset Parkinson's disease. This announcement comes less than a month ahead of the band's highly anticipated Las Vegas Sphere residency.