Hamas claims that Israel is thwarting the agreement as Shin Bet head Ronen Bar heads to Cairo for continued talks.
According to the letter, Biden saw the neurologist as part of his yearly physical in which he was also seen by other medical specialists.
According to polls, Trump even leads in some states where Democrats traditionally win, such as Nevada.
The White House has overwhelmingly limited Biden's live interviews and press conferences.
Netanyahu is due to address the US Congress on July 24 during a visit to Washington. He will speak to a joint session of the House of Representatives and the Senate.
Trump, 78, takes the stage as a felon who still faces a trio of criminal cases. Biden, 81, is under intense pressure to avoid verbal stumbles and deliver a convincing performance.
Discover the ten-year-old incident that led Netanyahu to accuse the White House of deceptive tactics regarding US arms deliveries to Israel.