I can provide some general context on the issue.
The decision to undergo cognitive function testing is a personal one for any individual, including public figures like politicians. The reasons why one person consents to such testing while another does not can vary and may be influenced by several factors, including privacy concerns, medical advice, political strategy, and individual beliefs.
In the case of Donald Trump, he publicly stated that he took a cognitive function test during his presidency to demonstrate his mental acuity and refute claims about his mental fitness. His decision might have been influenced by various factors, including public pressure, political considerations, or his own desire to address concerns about his cognitive abilities.
Regarding Joe Biden, if there are concerns about his cognitive abilities, those raising the issue may have differing opinions on whether cognitive function testing is necessary or appropriate. However, there were no public statements from Joe Biden or his administration suggesting that he had undergone a cognitive function test.
It's essential to recognize that any discussions about a public figure's mental health or cognitive abilities should be approached with care and respect. The topic can be sensitive and complex, and speculation about someone's mental state without concrete evidence can be misleading and potentially harmful.
As always, if there are concerns about a leader's health or fitness for office, it is appropriate for relevant medical professionals and experts to assess and address these matters in a responsible and ethical manner. Additionally, voters and citizens have the opportunity to raise questions and express their opinions through democratic processes.