Whenever the attendance of the injured employee's treating or consultant chiropractor, nurse practitioner, licensed clinical social worker, or psychologist by deposition or at a hearing is required, such chiropractor, nurse practitioner, licensed clinical social worker, or psychologist shall be entitled to a fee of $350. In instances involving special circumstances, the board may fix a fee in an amount greater than the said sum, such increased fee to be commensurate with the circumstances in the particular case. Where the attendance is pursuant to a subpoena issued by the board, the Workers' Compensation Law judge or any officer of the board so designated by the chair, the attendance fee may be limited to no more than $70.