In August, Johnson announced he would not participate in traditional political debates because of lingering speech problems. Dykstra has sought to keep that decision in the minds of voters.
"The Dykstra campaign wants to keep it very much front and center because it raises questions about the senator's verbal ability," says Elizabeth T. Smith, associate professor of political science at the University of South Dakota. "If you look on Joel Dykstra's website, they have T-shirts now that say 'Dykstra — No Debate About It.' "
Robert Grossmann, 71, a pastor in Johnson's hometown of Vermillion, says he expects Johnson to get a large sympathy vote.
"I have sympathy for the man myself; I hope things get better," Grossmann says. "I just really think he should have resigned or not run."
Lorri May, 46, of Madison heard Johnson speak at the state Democratic convention, where she was a delegate. "I don't think it has affected his ability to serve," she says.
Dykstra says he has tried to focus on issues, not Johnson's health. Still, Dykstra says, voters constantly ask him about it.
Michael Yochelson, medical director for brain injury programs at National Rehabilitation Hospital in Washington, says the senator has "made great strides."
"I hoped all along I would stay in politics and do my state some good," Johnson says. "But I didn't know if I could. But as time went on, I grew ever more confident that I could run for office again."
Martin reports for the Argus Leader in Sioux Falls, S.D.