Substantial Medical Evidence
In Blackledge v Bank of America (2010) 75 CCC 613, the court addressed what constitutes substantial medical evidence of whole person impairment under the AMA Guides and Almarez/Guzman II
Under the AMA Guides, a physician performs an evaluation to determine the WPI for the injured employee’s medical condition(s) expressed as a percentage. (AMA Guides, Section 2.1, at p. 18). The impairment evaluation includes a discussion of the employee’s history and symptoms, the results of the physician’s examination, the results of various tests and diagnostic procedures, the diagnosis, the anticipated clinical course, the need for further treatment, and the residual functional capacity and ability to perform activities of daily living. After considering all of these factors, the physician compares the medical findings for each condition with the impairment criteria listed within the Guides and then calculates the appropriate impairment ratings for the conditions. The physicians report should include a summary list of the impairments and impairment ratings by percentage, together with a calculation of the final WPI, and a statement of the rationale underlying the WPI opinion.
The opinion of a single physician may establish an injured employee’s WPI, provided that the opinion constitutes substantial evidence. Place v. WCAB (1970), 35 CCC 525, 529-530. Among other things, to constitute substantial evidence regarding WPI a physicians opinion must comport with the AMA Guides, including as applied and interpreted in published appellate opinions and en banc decisions of the Appeals Board. Hegglin v WCAB (1971) 36 CCC 93. Medical report and opinions are not substantial evidence … if they are based on incorrect legal theories. Zemke v WCAB (1968) 33 CCC 358, 360. An expert’s opinion which …assumes an incorrect legal theory cannot constitute substantial evidence.
Also, a physician’s opinion regarding WPI must set forth the physician’s reasoning, not merely his or her conclusions. Granado v. WCAB (1970) 33 CCC 647, 653
A physician’s mere conclusion not sufficient. Zemke p, 363. People v Bassett (1968) 70 Cal Rptr 193. The chief value of an expert’s testimony rests upon the material from which his or her opinion is fashioned and the reasoning by which he or she progresses from the material to the conclusion, and it does not lie in the mere expression of the conclusion; thus, the opinion of an expert is no better than the reasons upon which it is based.