In any claim for compensation, when the employee has been killed or is physically or mentally unable to testify, there is a rebuttable presumption that the employee received a personal injury arising out of and in the course of employment, that sufficient notice of the injury has been given and that the injury or death was not occasioned by the willful intention of the employee to injure or kill the employee or another.   [PL 1991, c. 885, Pt. A, §8 (NEW); PL 1991, c. 885, Pt. A, §§9-11 (AFF).]