Sen. John Fetterman (D-PA) has described his post-stroke auditory processing disorder symptoms, when they are their worst, as trying to listen to and interpret the teacher from the “Peanuts” cartoon, the New York Times reported Friday.

The freshman Senator from Pennsylvania suffered a stroke just days before the Democrat primary last year, though he still handily won the nomination. In the months that followed, Fetterman stayed out of the public eye while a general election race with Republican nominee Dr. Mehmet Oz approached, and public scrutiny ensued.

Fetterman dodged debates for months, prompting local and national newspaper editorial boards to pressure him to take the stage with Oz. When he finally began making public appearances, his trouble with communicating and speaking became alarmingly apparent, and at their lone debate, Fetterman relied on closed captioning to adequately understand the moderators and his opponent.

Despite it all, he handily beat out Oz for the seat, giving the democrats a 51-seat majority in the U.S. Senate.

But, as the Times reported Friday, Fetterman may have pushed it too hard on the campaign trail and “set himself back permanently,” and his transition into the U.S. Senate has proven to be a “difficult period.”

The publication’s Annie Karni wrote:

But aides and confidantes describe his introduction to the Senate as a difficult period, filled with unfamiliar duties that are taxing for someone still in recovery: meetings with constituents, attending caucus and committee meetings, appearing in public at White House events and at the State of the Union address, as well as making appearances in Pennsylvania.

The most evident disability is a neurological condition that impairs his hearing. Mr. Fetterman suffers from auditory processing issues, forcing him to rely primarily on a tablet to transcribe what is being said to him. The hearing issues are inconsistent; they often get worse when he is in a stressful or unfamiliar situation. When it’s bad, Mr. Fetterman has described it as trying to make out the muffled voice of the teacher in the “Peanuts” cartoon, whose words could never be deciphered.

 The stroke — after which he had a pacemaker and defibrillator implanted — also took a less apparent but very real psychological toll on Mr. Fetterman. It has been less than a year since the stroke transformed him from someone with a large stature that suggested machismo — a central part of his political identity — into a physically altered version of himself, and he is frustrated at times that he is not yet back to the man he once was. He has had to come to terms with the fact that he may have set himself back permanently by not taking the recommended amount of rest during the campaign. And he continues to push himself in ways that people close to him worry are detrimental.

In October, Dr. Clifford Chen, MD, who apparently contributed to Fetterman’s campaign, wrote a letter for the candidate saying he “has no work restrictions and can work full duty in public office,” as Breitbart News reported. He noted that Fetterman was still enduring symptoms of auditory processing disorder.

His speech was normal and he continues to exhibit symptoms of auditory processing disorder which can come across as hearing difficulty,” wrote Chen. “Occasional words he will ‘miss’ which seems like he doesn’t hear the word but it is actually not processed properly.” 

On Wednesday – just over a month into his term – Fetterman was taken to the hospital after feeling “lightheaded,” as Breitbart News reported.

“Towards the end of the Senate Democratic Retreat today, Senator John Fetterman began feeling lightheaded. He left and called his staff, who picked him up and drove him to the George Washington University Hospital,” a statement from his read.

On Thursday, Fetterman’s Communications director Joe Calvello announced that testing, including an MRI, “rule out a new stroke” but noted he was “being monitored with an EEG for signs of seizure.” He emphasized that there had been “no signs” of a seizure as of Thursday night.

Fetterman made headlines earlier in the week after bringing a convicted murderer as his guest to the State of the Union.