57. The right to an income replacement indemnity is extinguished from the earliest of the following events:(1) when the worker is again able to carry on his employment, subject to section 48;
(2) the death of the worker; or
(3) the sixty-eighth birthday of the worker or, if he suffers an employment injury when 64 years of age or over, four years after the date he became unable to carry on his employment.