At any hearing, the department shall consider its official records and may receive sworn testimony. At the hearing, or subsequent to the hearing with the consent of the applicant or licensee, any or all of the following may be submitted as evidence concerning any fact relating to the ability of the applicant or licensee to safely operate a motor vehicle:
(a) Reports of attending or examining physicians and surgeons.
(b) Reports of special investigators appointed by the department to investigate and report upon any facts relating to the ability of the person to operate a vehicle safely.
(c) Properly authenticated reports of hospital records, excerpts from expert testimony received by the department or a hearing board upon similar issues of scientific fact in other cases, and the prior decision of the director upon those issues.