The approach to assessing impairment for headaches differs among the fourth, fifth, and sixth editions of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides). In summary, the fourth edition provides only a qualitative, nonnumeric rating. In the fifth edition, an examiner can give up to 3% whole person permanent impairment. Using the sixth edition of the AMA Guides, an examiner may determine up to 5% whole person permanent impairment for migraine headaches for Chapter 13 and up to 3% whole person impairment for other headaches according to Chapter 3. With respect to the AMA Guides, Fourth Edition, unless other objective features can be rated according to specific organ dysfunction, headache impairment is a qualitative, nonnumeric rating, and “The vast majority of patients with headache[s] will not have permanent impairments.” In some defined cases, the fifth edition facilitates calculation of a pain related impairment score (that specifically is not an impairment rating) that is used to describe the severity of the pain, for which up to 3% whole person impairment may be provided. The sixth edition of the AMA Guides provides a quantitative whole person impairment rating up to 5% whole person impairment for migrainous headaches and 3% whole person impairment for nonmigrainous headaches.