Sen. Susan Collins (R-Maine) has revealed she has long lived with a benign essential tremor after she launched her re-election campaign for a sixth term in the US Senate . Collins, 73, disclosed the condition — which causes visible shaking in her hands, head and voice — publicly for the first time on Wednesday while she insisted that it has not impacted her ability to serve in office. “I have had it for the entire time that I have served in the United States Senate,” Collins told NEWS CENTER Maine . “It has absolutely no impact on my ability to do my job or on how I feel each day.” Maine Sen. Susan Collins has revealed she has lived for decades with a benign essential tremor. Getty Images Collins, first elected in 1996, said she has never missed a Senate floor vote during her nearly 30 years in office — a streak approaching 10,000 consecutive votes — and pointed to that record as evidence she remains healthy enough to continue serving.…