Q: Do you know of any case authority which allows denial of a California cumulative trauma claim based on lack of medical evidence?

A: Yes. Amelia Mendoza v. Huntington Hospital ADJ6820138 and ADJ6020197 suggests in dicta the following:

One basis for a timely denial is that the applicant has not presented any medical evidence to support industrial causation. In this regard, it is the employee’s burden to prove industrial causation, not the defendant’s burden to disprove causation. (Lab. Code, §§ 3202.5, 5705.) Similarly, another basis for a timely denial is that the applicant’s medical evidence on industrial causation is not legally substantial, e.g., the medical opinion is not predicated on reasonable medical probability; the medical opinion is based on facts no longer germane, on inadequate medical histories or examinations, on incorrect legal theories, or on surmise, speculation, conjecture, or guess; or the medical opinion does not set forth the facts and reasoning behind its conclusions. (See Escobedo v. Marshalls (2005) 70 CCC 604, (en banc).)”

While this case is not necessarily binding authority, it is certainly persuasive legal authority supporting denial of a cumulative trauma claim based on lack of medical evidence.