Is a physician's certificate necessary to apply for a section 118.3 tax credit?

In Cusson v. M.N.R., [1993] 1 C.T.C. 2471 the headnote reads: "The appellant claimed a tax credit pursuant to section 118.3. She had had a mastectomy which she claimed caused her much discomfort. The physician's certificate which the appellant filed certified the existence of a prolonged but minor impairment. At issue was whether the appellant had suffered a severe and prolonged physical impairment within the meaning of subsections 118.3(1) and 118.4(1). Held: A certificate by a medical doctor stating that the individual is suffering from a severe impairment was essential. The medical doctor only certified the existence of a minor impairment. That was insufficient. Appeal dismissed." Lamarre Proulx, T.C.J. said at page 2472: "A certificate by a medical doctor stating that the individual is suffering from a severe impairment is essential to the application of these provisions, i.e. subsections 118.3(1) and 118.4(1)"