The testimony of any witness or party may be taken by deposition or interrogatory according to the rules of practice of the Federal district court for the judicial district in which the case is pending (or of the U.S. District Court for the District of Columbia if the case is pending in the District or outside the United States), except that at least 30 days prior notice of any deposition shall be given to all parties unless such notice is waived. No post-hearing deposition or interrogatory shall be permitted unless authorized by the administrative law judge upon the motion of a party to the claim. The testimony of any physician which is taken by deposition shall be subject to the limitations on the scope of the testimony contained in §725.457(d).