Cortical changes in dental technicians exposed to vibrating tools.

To study the cortical reorganization after long time exposure to hand-held vibrating tools, we investigated 10 dental technicians with sensory neuropathy after long time exposure to vibrating tools and 10 controls for cortical changes using functional magnetic resonance imaging at 3 T. The activated volumes corresponding to individual fingers in the hand area of S1 were significantly larger in the neuropathy group than in controls. Activation in the primary motor cortex did not differ significantly from controls. These changes are likely the result of cortical reorganization following long-term non-physiological sensory input and they can partly explain the symptoms seen in vibration-induced neuropathy.