40 ILCS 5/9-158
Proof of duty or ordinary disability shall be furnished to the board by at least one licensed and practicing physician appointed by or acceptable to the board, except that this requirement may be waived by the board for proof of duty disability if the employee has been compensated by the county for such disability or specific loss under the Workers' Compensation Act or Workers' Occupational Diseases Act. The physician requirement may also be waived by the board for ordinary disability maternity claims of up to 8 weeks. With respect to duty disability, satisfactory proof must be provided to the board that the final adjudication of the claim required under subsection (d) of Section 9-159 established that the disability or death resulted from an injury incurred in the performance of an act or acts of duty. The board may require other evidence of disability. Each disabled employee who receives duty or ordinary disability benefit shall be examined at least once a year or a longer period of time as determined by the board, by one or more licensed and practicing physicians appointed by the board. When the disability ceases, the board shall discontinue payment of the benefit.
40 ILCS 5/9-158