In the lone debate in a Pennsylvania contest that may help determine whether Democrats retain control of the Senate, Democratic candidate for the U.S. Senate John Fetterman and Republican contender Mehmet Oz traded blows on themes ranging from crime to inflation.

Since the summer, Donald Trump supporter Oz, a 62-year-old celebrity doctor, has surpassed Fetterman, the state’s 53-year-old lieutenant governor, in the polls as voters’ perceptions of President Joe Biden’s Democrats have been more negative.

The debate represents a major political test for Fetterman, who suffered a stroke in May that left lingering problems with his speech and hearing that sometimes cause verbal miscues. The debate hall included two closed-caption monitors posted above the moderators that relayed dialogue to Fetterman.

Fetterman, who spoke haltingly and repeated phrases at times, addressed his health issues in his opening statement, calling it the elephant in the room.

“I had a stroke. [Oz] never let me forget that. And I might miss some words during this debate, mush two words together, but it knocked me down but I’m going to keep coming back up,” Fetterman said.

He later refused to commit to releasing his private medical records. “Transparency is about showing up. I am here for the debate,” he said.

U.S. inflation has hit 40-year highs, inflicting pain on consumers and forcing Democrats such as Fetterman to play defense on an issue that polling shows is voters’ top concern. Oz and Republicans have sought to tie Democrats’ big-spending bills combating issues including COVID-19 and climate change to rising consumer prices.