The members of the board or any one of them or an administrative law judge may, upon the application of either party or upon their own motion, appoint one or more disinterested and duly qualified physicians or surgeons to make any necessary medical examination of the employee and to report or testify with respect thereto. The physicians or surgeons shall be allowed travel expenses and a reasonable fee, to be paid by either or both parties or by the state, as directed by the board, any member thereof, or an administrative law judge.