An investigative committee of the U.S. Federal Circuit Court of Appeals rejected a request by Judge Pauline Newman, 95, to transfer the probe to another circuit.
The Washington-based Federal Circuit said it will not comment on the order or other related documents it released on Tuesday.
"Though it is difficult to say this, I believe Judge Newman is simply losing it mentally," one staffer told judicial investigators.
The Federal Circuit disclosed the probe last month, citing concerns about Newman's ability to handle cases and her refusal to cooperate with the investigation.
Newman was appointed by President Ronald Reagan in 1984 to the patent law-focused Federal Circuit, which often hears major cases involving technology and pharmaceutical companies.