In respect of any claim for compensation by an officer or employee of the Workers' Compensation Board or the State Insurance Fund, whether or not such claim is required to be determined by a neutral outside arbitration process pursuant to section 303.3 of this Part, the Workers' Compensation Law judge or arbitrator making the initial finding of fact concerning any medical issue present in the case shall develop the record with opinion evidence from an impartial specialist who is an expert in the appropriate medical specialty. Such impartial specialist shall be subject to cross-examination at the request of any party in interest.