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Enough with the worrying, former Vice President Joe Biden's brain surgeon says.

As some voters murmur that the gaffe-prone Democratic presidential candidate's age is cause for extra concern this campaign cycle, Dr. Neal Kassell — the man who performed surgery on Biden three decades ago following two brain aneurysms — came out swinging for his former patient.

Kassell dismissed fears about the 76-year-old Biden's mental faculties, noting that he's "as sharp as he was 31 years ago" and assuring people that the hemorrhage and subsequent operations did not result in any brain damage. "I am going to vote for the candidate who I am absolutely certain has a brain that is functioning," Kassell told Politico. "And that narrows it down to exactly one."

Biden's physician, Dr. Kevin O'Connor, backed up Kassell. "Vice President Biden is in excellent physical condition," he said. "He is more than capable of handling the rigors of the campaign and the office for which he is running."

In fact, several experts told Politico that voters are placing too great an emphasis on the age of several candidates, particularly the five septuagenarians who are running, including Democratic candidates Biden and Sen. Elizabeth Warren (D-Mass.), 70, and Sen. Bernie Sanders (I-Vt.), 77, as well as 73-year-old President Trump and his lone Republican challenger, former Massachusetts Gov. Bill Weld, who is 74.

"They have prospects for survival that extend well beyond the four-year term of the office," said Dr. Jay Olshansky, who led an American Federation of Aging Research study last month that sought to determine how likely it is that a candidate would die while in office. "The bottom line is their chronological age does not matter at all." Read more at Politico.