The first presidential debate of 2024 left many Americans and even some traditional Democratic allies wondering about President Biden’s mental fitness for office based on what appeared to be his unclear train of thought at times and his raspy voice on Thursday night.

The White House responded to these concerns, claiming that the president, who is 81, was fighting a cold, but some doctors said they perceive the health issues go beyond the sniffles — with one noting that “it is an issue of fitness, not of age.”

Dr. Brett Osborn, a Florida neurosurgeon who specializes in cognitive function, told Fox News Digital on Friday about his concerns. 

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“President Biden’s performance in [Thursday] night’s debate reignited longstanding discussions about his cognitive abilities and his overall leadership capacity,” Osborn told Fox News Digital. 

“Throughout the evening, Biden struggled to maintain a coherent narrative, often losing his train of thought mid-sentence, and providing vague, rambling and undecipherable answers to highly critical questions,” said Osborn, expressing his professional opinion.

“His frequent pauses, stumbling over words and reliance on notes underscored concerns about his mental acuity,” Osborn added. 

“Biden struggled to maintain a coherent narrative, often losing his train of thought mid-sentence.”

These seeming signs of cognitive decline highlight a “growing inability” to manage the complexities required by the job of the presidency, according to the neurosurgeon.

“His difficulty in articulating clear, concise responses and his apparent disorientation during the debate were seen by many – including his own constituents – as very troubling indicators of his overall health and an obvious decline in his cognitive function,” Osborn said.

Former President Donald Trump and President Joe Biden are shown during the first presidential debate of the 2024 election at CNN’s studios in Atlanta, Georgia, on Thursday, June 27, 2024. (Jabin Botsford/The Washington Post)

“President Biden lacks the mental sharpness required for the highest office in the land … especially amid [today’s] current national and international crises.”

The neurosurgeon, who has not treated Biden personally, also mentioned the 46th president has undergone multiple surgeries for brain aneurysms.

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There is a famous saying in neurosurgery, Osborn noted: “When the air hits your brain, you’re never the same.” 

The surgeon surmised, “The odds have been stacked against him for years, long before his presidency.”

Joe Biden reacts as supporters greet him at his debate watch party at Hyatt Regency Atlanta on June 27, 2024, in Atlanta, Georgia. (Derek White/Getty Images for DNC)

Dr. Marc Siegel, physician, clinical professor of medicine at NYU Langone Medical Center and a Fox News medical contributor, also spoke with Fox News Digital about concerns from his end.

“The debate is, in a way, a psychiatric or cognitive stress test,” he told Fox News Digital. 

Although Biden was able to respond to questions and seemed to be spatially aware, according to Siegel, the president did display “frequent disorientation” and had “problems with spontaneity or redirecting,” the doctor said. 

He has not personally examined Biden.

Dr. Marc Siegel, at right, joined “Fox & Friends” on Friday, June 28, to discuss the presidential debate on Thursday evening.  (Kevin D. Liles for The Washington Post via Getty Images; Fox News)

Siegel described Biden’s speech as “meandering,” noting that he ended sentences in different places than intended, and “often mixed up ‘trillions’ and ‘billions’ and ‘millions.’”

Siegel confirmed that a physical illness, even with a cold, can bring out cognitive issues “even more.”

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“Even so, it’s hard to believe this is all from a cold,” Siegel told Fox News Digital. “Either way, we need someone who is sharp despite a cold.” 

The NYU Langone physician noted that cognitive issues “wax and wane,” so they won’t always present the same way.

President Joe Biden looks over at former President Donald Trump during the first presidential debate of the 2024 election season on June 27, 2024.  (Andrew Caballero-Reynolds/AFP via Getty Images)

While the age of both candidates has been raised as a concern, Siegel countered that what’s important is a president’s physical and mental fitness.

“It is an issue of fitness, not of age,” he said. “It is an issue of mental acuity, which is especially important if there is a crisis.” 

While Biden is 81 (he turns 82 in November), Trump is 78 years old. 

During an appearance on “Fox & Friends” on Friday morning, Siegel also spoke about the possibility of cold medications impacting Biden’s performance.

“It is an issue of fitness, not of age. It is an issue of mental acuity.”

“None of the medications that he would be taking for a cold, except something that might make him drowsy, would be relevant here,” he said. 

“And I don’t think they would give him something that would make him drowsy before a debate,” he said.

He added, “We’ve been watching this a long time. This is something progressive.”

Fox News Digital reached out to the Biden campaign and to the White House press office for comment.

Earlier this year, concerns emerged about Biden’s age and memory after the release of a special counsel’s report.  (AP Photo/Damian Dovarganes)

Earlier this year, concerns emerged about Biden’s age and memory after the release of a special counsel’s report. The report described the Democrat’s memory as “hazy,” “fuzzy,” “faulty,” “poor” and having “significant limitations,” the Associated Press noted at the time.

The report indicated that Biden could not recall certain milestones in his own life, such as the date his own son Beau died of brain cancer, as Fox News Digital reported at the time. (Beau Biden passed away on May 30, 2015.)

“My memory is fine,” Biden responded afterward from the White House. 

“A person with growing problems of memory and judgment is frequently the last to acknowledge it.”

The New York Times editorial board and others have called on Biden to step out of the race after his debate performance. 

Vice President Kamala Harris acknowledged that Biden had a “slow start” to the debate, but she defended his performance overall and his record during his time in the White House.

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Said Dr. Siegel in a New York Post opinion piece that ran in the publication on Saturday morning, “This isn’t a question of age. Cognition varies widely with age, and it isn’t fair to say that executive function is automatically impaired at a certain point in life. But it’s a sad medical fact that a person with growing problems of memory and judgment is frequently the last to acknowledge it.”

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