In recent weeks, the mental acuity of US President Joe Biden has come under intense scrutiny due to his verbal gaffes, shaky voice, and other troubling signs. Now, health experts are urging both Biden and his rival, former President Donald Trump, to undergo additional cognitive tests to shed light on their mental abilities. However, these experts caution against drawing conclusions without a thorough examination.

Cognitive tests, according to experts, could potentially refute speculation that the 81-year-old president's mental state is in worrying decline or confirm it. The tests could also provide insights into the mental capabilities of Trump, who has had his own share of verbal lapses. Nevertheless, these experts emphasize that reliable diagnoses cannot be made from a distance.

Following Biden's widely criticized performance in a debate with Trump two weeks ago, the Democratic candidate's campaign has faced increasing opposition, with a growing number of officials within his own party questioning his ability to lead the country for another four years. Biden's mistake at a summit in Washington, where he inadvertently introduced Ukrainian President Volodymyr Zelensky as Russian President Vladimir Putin before quickly correcting himself, further fueled concerns.

One neurologist, Harvard Medical School's Dennis Selkoe, highlights the need to determine whether Biden's condition is simply a normal age-related process or indicative of a neurologic disease. Selkoe clarifies that making an error with a name does not automatically signify dementia or Alzheimer's. However, he notes that Biden exhibits certain traits resembling those of an early Parkinson's patient, such as a slow and stiff gait, as well as a low and sometimes barely audible voice, possibly indicating a condition known as hypophonia.

In February, Biden underwent a comprehensive physical examination, including an "extremely detailed neurologic exam" that reportedly ruled out Parkinson's disease. However, the exact tests conducted and their results were not disclosed. This raises the question of whether a neurological illness could have developed in the past five months, as comprehensive exams in February should have detected early signs of any nascent condition.

In March, the scientific journal Lancet called for standardized procedures to assess the health of sitting and potential presidents, aiming to protect American voters from speculations and disinformation. Without such reliable testing, the public is left to rely on reports voluntarily released by politicians' personal physicians.

Experts, such as aging specialist Jay Olshansky from the University of Illinois at Chicago, advocate for complete transparency. Olshansky urges both major presidential candidates to undergo a cognitive test, a challenge frequently directed at Biden by former President Trump. Several tests, including the MMSE and the MoCA, are available for screening or as part of a comprehensive battery of exams.

While Biden has asserted that he effectively passes a cognitive test every day by carrying out his presidential duties, Selkoe points out that the ability to perform familiar tasks is different from tasks that require recalling a list of words heard five minutes earlier, as some tests demand.

During a news conference, Biden stated that he would be open to taking a new neurological exam if recommended by his doctors. However, he noted that currently, no one is suggesting it. Meanwhile, aging specialist Allison Sekuler from the Baycrest Academy cautions that aging impacts the brain, leading to the build-up of "garbage" and atrophy of parts crucial to memory. Sekuler suggests that both Biden and Trump undergo testing due to their demonstrated difficulties in staying on track during recent debates.

Addressing the issue of ageism, Olshansky criticized the use of a walker as a symbol of the Biden-Trump race on a recent magazine cover. He encouraged recognizing the strength of "crystallized intelligence" in older individuals, which refers to the ability to use past experiences to improve reasoning skills. Olshansky's 2020 study indicated a 95 percent chance of Biden surviving a first term based on average life expectancy and personal risk factors. However, a new calculation for an older Biden gave him a lower probability of survival at just 75 percent.