Workmen's compensation has been defined as a system of social legislation providing compensation for loss resulting from the disablement or the death of workmen through industrial accident, casualty or disease. ... Recovery for an injury sustained in a workmen's compensation case is dependent upon the existence of all of the following six factors: (1) Jurisdiction of the subject matter; (2) Amenability of employer; (3) Proof of contract of employment; (4) Showing of a work related occurrence; (5) Sustaining of an injury as defined under the Workmen's Compensation Act; and (6) Proof of a causal relationship between the disabling condition and the injury received whether by direct causation, acceleration or by aggravation. It is this last area and especially the question of causation through means of acceleration or aggravation which warrants further discussion and examination.
Allyn D. Kendis & James D. Kendis, Aggravation under Workmen's Compensation, 17 Clev.-Marshall L. Rev. 93 (1968)