 Live from NPR News in Washington, I'm Dave Mattingly. The White House is responding to questions about a neurologist with expertise in Parkinson's disease, having visited the White House eight times in eight months. Visitor logs show Dr. Kevin Kennard, who works at Walter Reed National Military Medical Center, met once with the president's personal physician, Dr. Kevin O'Connor. In a letter, O'Connor says the president has not seen a neurologist outside of his annual physical.