• Senate Minority Leader Mitch McConnell is "medically clear" to continue working, the physician for the U.S. Congress said after the Kentucky Republican froze during a press conference.
• "Occasional lightheadedness is not uncommon in concussion recovery and can also be expected as a result of dehydration," Dr. Brian Monahan said in a letter.
• McConnell, 81, had suffered a concussion in March after a fall.
• President Joe Biden said McConnell sounded like "his old self" when he called him on the phone.

Senate Minority Leader Mitch McConnell is "medically clear" to continue working, the attending physician for the U.S. Congress said one day after the Kentucky Republican froze during a press conference for the second time this summer.

"Occasional lightheadedness is not uncommon in concussion recovery and can also be expected as a result of dehydration," Dr. Brian Monahan said in a letter shared Thursday from McConnell's office.

The doctor was referencing a concussion that McConnell, 81, had suffered in March after a fall at a political fundraiser.

Monahan said he has "consulted with Leader McConnell and conferred with his neurology team," and gave him the all-clear after "evaluating yesterday's incident."

That incident came at the start of a Wednesday afternoon press conference in Covington, Kentucky, when McConnell abruptly stopped speaking and stared straight ahead for about 30 seconds.

He appeared to fail to respond when an aide approached him to ask if he had heard a reporter's question. McConnell had been asked for his thoughts about running for reelection.

The episode echoed a similar health scare in July, when McConnell suddenly froze and was briefly unable to speak at a news conference in Washington, D.C.

But Monahan said in Thursday's letter that he has "informed Leader McConnell that he is medically clear to continue with his schedule as planned."

The physician's assessment was backed up later Thursday by President Joe Biden, who said McConnell sounded like "his old self" when he called him on the phone.

"It's not at all unusual to have the response that sometimes happens to Mitch, when you've had a severe concussion," Biden said during a surprise visit to FEMA headquarters.

"It is part of the recovery. And so I'm confident he's going to be back to his old self," Biden said.

The Democratic president had wished McConnell well after his fall in March, and the senator said the president had called him up following his verbal freeze in July. "I told him I got sandbagged," McConnell said he told the president at that time.

An aide to McConnell had previously described the lapse in Covington as the result of the senator feeling "momentarily lightheaded."

McConnell participated in a discussion with Rep. Jim Banks, R-Ind., later Wednesday evening, his office confirmed to CNBC.

McConnell's health is a growing cause for concern among some of his Senate colleagues, according to Politico, which reported that some GOP members are weighing whether to force a special conference meeting about the Republican leader's recent incidents.