With the race to determine Pennsylvania’s next U.S. senator tightening, Lieutenant Governor John Fetterman’s doctor stepped in Wednesday to reassure the public about the Democrat’s health and mental fitness ahead of a much anticipated debate.

In a letter released Wednesday, Clifford Chen wrote that Mr. Fetterman is “recovering well from his stroke and his health has continued to improve.”

“He spoke intelligently without cognitive deficits,” the doctor said. “His speech was normal and he continues to exhibit symptoms of an auditory processing disorder which can come across as a hearing difficulty.”

According to the doctor, Mr. Fetterman’s condition is characterized by occasionally missing words, which he said “can come across as hearing difficulty.” He also assured that the candidate has “no work restrictions and can work full duty in public office.”

Mr. Fetterman’s health has been in the spotlight following questions from an NBC News reporter and due to his need for closed captioning during an interview.

The reporter asked whether Mr. Fetterman understood her questions, which led many to wonder whether he was physically fit for office. Mr. Fetterman called her comments a “disservice” to the reporter’s craft, and said that it “was appalling to the entire disability community, and I think to journalism.”

An AARP poll released Wednesday showed Mr. Fetterman leading Mehmet Oz by two points in the race, 48 percent to 46 percent — a four-point swing from the group’s previous poll.

In the days before the release of the doctor’s note, Mr. Fetterman and his campaign had been maneuvering to redirect attention back onto Dr. Oz. The clearest example of this was the launch of a site called “fettermeme.com,” which hosts an archive of footage of Dr. Oz, and encourages visitors to generate their own memes about the Republican candidate.

The archive includes categories focusing on Dr. Oz’s perceived weaknesses as a candidate, such as “Magic Pill,” “Jersey,” and “Out of Touch.”

“Magic Pill“ references Dr. Oz’s reputation for selling dubious remedies on television, while “Jersey“ mocks the candidate for living in New Jersey until late 2020. Calling Dr. Oz “Out of Touch” with the average Pennsylvanian is a common refrain from Mr. Fetterman’s campaign.

Mr. Fetterman’s wife, Gisele Fetterman, has also been highly active and visible on the campaign trail of late, in sharp contrast to her husband, who has been largely sequestered for a candidate.

That’s all about to change on October 25, when Mr. Fetterman is scheduled to debate Dr. Oz. He will also be using captioning to assist with his auditory processing issues during the debate.

According to a political scientist at John Jay College, Brian Arbour, “this is relatively unprecedented territory for a highly contested, high-profile election.” He does note, though, that both campaigns appear to think the newly unveiled doctor’s note will matter.

“How it actually affects voters — we don’t have much history on this stuff but there’s still a lot of speculation,” Mr. Arbour told the Sun.

There are a number of other factors at play in the race, apart from questions surrounding Mr. Fetterman’s recovery, that explain the tightening poll numbers.

“One is that it always seemed that Oz was underperforming what he should be, and therefore the set of undecided voters were probably more in favor of Oz,” Mr. Arbour said.

At this point in the campaign, some voters who were previously unenthusiastic about Dr. Oz as a candidate are now prepared to vote for him, regardless of the reasons they might have felt unenthusiastic in the first place.

Another factor is that the political environment in the country has improved for Republicans in the past month, with stubborn inflation, rising crime, and immigration as issues.

“Some of this is expected,” Mr. Arbour said. “We have a swing state that’s had a bunch of close elections recently that’s going to have another close election this year.”