Analysis: AMA 6th Edition Would Reduce Benefits

Thursday, January 24, 2008 | 0

The AMA Guides to the Evaluation for Permanent Impairment, 6th Edition is now available from the American Medical Association. WorkCompCentral received its copy for review last Friday and has obtained feedback about this new edition from our WorkCompSchool faculty. Rene Thomas Folse, J.D., Ph.D., instructor for the WorkCompSchool course, “Demystifying the AMA Guides” has provided his opinion on the 6th Edition in the following editorial.

By Rene Thomas Folse, JD, PhD

The AMA Guides was first published in 1971, and new editions were published throughout the years with the 5th Edition arriving in 2000. Each new edition was controversial in some way such that not all states automatically or routinely legislated the use of the newer editions. Today, some states still use parts of the 3rd and 4th Editions, and some states refuse to use the AMA Guides at all. In California, Labor Code § 4660 mandates the use of the 5th Edition of the AMA Guides. Thus, California cannot use the newly published 6th Edition without a specific legislative amendment to Labor Code Section 4660.

The initial adoption of the AMA Guides in California in January 2005 was indeed controversial since ratings for injured workers were reduced dramatically. According to one study that compared the ratings of 250 California cases under the old and new methods which was published in the July/August 2005 AMA Guides Newsletter:

“Of the total 250 cases, including those with no documented evidence of ratable impairment, the mean final permanent disability rating under the new schedule was 6.4%, with a range of 0% to 67%. The mean PD rating under the old schedule was 22.0%, with a range of 0% to 100%. This reflects a decrease of 71%.”

My initial quick review of this newest edition of the AMA Guides was to determine if there are major changes that might stimulate political controversy from either the workers or the employers surrounding any proposed legislative adoption of this new edition.

It would seem from the analysis below, that the 6th Edition of the AMA Guides would further reduce impairment awards to injured workers if adopted in California.

There are major changes in the new spine chapter, which is now Chapter 17. My first review of the new spine chapter reveals that a rating for injured workers with spine injures has gone from bad to worse under the 6th Edition. The 5th Edition uses two methods to evaluate spines, the DRE or Diagnostic Related Estimate method and ROM or Range of Motion method. Of these two methods, in many cases the ROM method would produce the higher impairment. This assumption was confirmed in an article that appeared in the July/August 2006 AMA Guides Newsletter that stated, “Typically, the ROM Method will result in a higher rating than the DRE Method, with the notable exception of cervical spine fusions.”

Under the 6th Edition, the more liberal ROM method has been eliminated, and only the DRE method remains, and that method has been modified. There remains five classes of impairment under the DRE method, with the potential highest value being lowered from 35%-38% to 25%-30% for cervical injures, from 25%-28% to 17%-22% for thoracic injuries, and increased from 25%-28% to 25%-33% for lumbar injuries. Corticospinal injury that occurs in the worse spine injury remains rated under the neurological chapter, and my review of the neurological chapters below shows that those tables have been lowered as well. Overall, the rating potential for spine injury is lower under this new edition.

The 5th Edition pain chapter provided up to a 3% “add-on” for pain. The new pain chapter indicates that there is no longer a pain add-on if the injury or illness can be rated objectively using chapters 4 through 17. The maximum value for rating under the new pain chapter remains 3% but is to be provided only where there are no objective findings ratable elsewhere. There was much criticism of the treatment of pain under the AMA Guides 5th Edition with many believing that 3% was inadequate. It would appear that the criticism would continue with the 6th Edition. Philipp M. Lippee M.D. who was the chapter chair for the pain chapter in the 3rd, 4th, and 5th Editions of the Guides, and who was highly critical of the AMA for selecting the 3% value in the 5th Edition by way of what he termed editorial “fiat” is noticeably missing as a contributor to the new 6th Edition pain chapter. Injured workers for the most part will have lower ratings since they can no longer make use of the new pain chapter if they are rated elsewhere.

Under the 5th Edition, internal medical injures in chapters 3, 4 and 5 had a maximum impairment rating of 100% for each of the tables in those chapters. Internal medicine provided the most liberal chapters in the 5th Edition. The 6th Edition has lowered the maximum value in each of the equivalent tables in these chapters to 65%, seemingly across the board. The 5th Edition hypertension chapter has been deleted as a separate chapter, and the table included in section 4.7 of the Cardiovascular chapter, and the maximum value lowered from 100% in the 5th to 65% in the 6th Edition. It seems clear that the 6th Edition has drastically lowered the impairment ratings for internal injuries without exception or explanation.

The maximum value for impairment caused by a hernia remains at 30% under chapter 6 of both the 5th and 6th Editions. The 6th Edition adds additional categories with a finer gradation of impairment for the various factors considered.

In some cases injured workers claimed impairment for sexual dysfunction arising out of their injures under chapter 7 of the 5th Edition.. The 6th Edition lowered the maximum value for men from 20% to 15%, and for women from 35% to 20% for these claims.

Impairment of the skin is treated under chapter 8 of both editions. Skin impairment in industrial cases can arise out of such injuries, such as scarring following trauma, or as a result of dermatitis following chemical exposures. The tables for such impairments in the 5th Edition had maximum impairment values of 85%-95% . The equivalent tables under the 6th Edition have been reduced to 45%-58% for maximum values. Chapter 8 of the 6th Editions is clearly worse for an injured worker with skin impairment.

The values for binaural hearing loss under chapter 11 of both editions appear to be unchanged with the maximum impairment specified at 35%. Both editions allow up to a 5% add on for tinnitus. Similarly, the maximum values for vision impairment ratings in chapter 12 of both editions shows minor changes with maxim values at 85% for total loss of vision. Ratings should not be profoundly higher or lower for hearing or vision impairment under the new 6th Edition.

Chapter 13, Central and Peripheral Nervous System, may be one chapter where there has been one table changed for the workers benefit. An often-cited example of the conservative nature of the AMA Guides was table 13-2 of the 5th Edition that indicated that someone who had “irreversible coma requiring total medical support” could be given no more than 90% whole person impairment. Under the 6th Edition, the new table 13-4 for the same circumstance would now allow 100% to be given. This is now perhaps the only clear example of what the AMA Guides perceives to be a 100% impairment of the whole person. Many of the other tables in Chapter 13 have lowered the maximum permanent impairment. For example, the maximum value in the table for Episodic Loss of Consciousness or Awareness has been lowered from 70% to 50%, and Sleep and Arousal Disorders have been lowered from 90% to 50%.

Several of the tables in Chapter 13 that are to be used for cortical spinal injuries in addition to the rating in the spine chapter. In the 5th Edition, these tables were repeated word for word in the spine chapter, and in the 6th Edition they appear only in chapter 13, but the language of the spine chapter continues to allow the use of both chapters for the most serious spine injury. Nonetheless, those tables in chapter 13 appear to have all been lowered from the values specified in the 5th Edition. For example, impairment of Station and Gait has been lowered from a maximum of 60% to 50%,, Neurgenic Bladder lowered from 60% to 30%, Neurologic Impairment of Respiration lowered from 90% to 65% and the other tables have had similar reductions. Thus, with the sole exception of irreversible coma now receiving 100%, the rest of Chapter 13 lowers maximum impairment ratings seemingly in most if not all other tables.

California does not use the AMA Guides to rate psychiatric impairment since Labor Code Section 4660 specifies that the AMA Guides is to be used for rating “physical” injuries only, thus excluding non-physical (i.e. psychiatric) injuries from the mandates of S.B. 899. The 5th Edition of the AMA Guides did not provide whole person impairment values for mental impairment. The 6th Edition does attempt to compute these values by averaging scores from three instruments including the GAF scale, which California now uses. The maximum value for the most severe GAF score is 50% under the new AMA Guides. The same GAF scale score now used in California provides 90% whole person impairment. If the California legislature amends Section 4660 to mandate the use of the 6th Edition and also specifies that the AMA Guides is to be used to rate psychiatric as well a physical injuries, the maximum value of such injuries will be lowered for mental injuries under the 6th Edition.

Chapters 15 (upper extremities) and 16 (lower extremities) continue to provide maximum values of 60% and 40% respectively for those chapters, the same value in both editions. The approach to calculating the values of impairment has been changed in significant ways, and it is unclear at this time if the new approach will produce a change in values awarded to injured workers. It certainly will not provide higher ratings since nothing can exceed these maximum values.

The Combined Values Chart (CVC) shown at the end of the 6th Edition uses the identical formula (A+B(1-a)) for combining impairments as in the 5th Edition and thus the combining method is unchanged. There have been criticisms of using a purely mathematical approach to combining impairment in certain instances where the functional effect of two injures may be profoundly more than the CVC mathematical approach would compute. In an article that appeared in the March/April 2002 AMA Guides Newsletter this anomaly was confirmed by the author who stated “From a functional perspective, in certain circumstances the combined effect of two impairments may be both more significant than either impairment alone or even the impairment reflected by the combined or additive value of the two impairments.

However, in all circumstances the combining of two values, using the Combined Values Chart, will result in a value equal to or less than the adding of two values.” Despite this obvious and acknowledged limitation of mechanically using the CVC for combining injuries, the 6th Edition of the AMA Guides has not provided any solution to this known limitation. California to some extent has circumvented this limitation by way of labor code §4662 which provides a conclusive presumption of total disability for certain combinations of injuries, such as the loss of sight in both eyes. Even so, one would have hoped that the 6th Edition of the AMA Guides would have attempted to address this issue that they acknowledged in their Newsletter back in 2002.


My first glance at the 6th Edition of the AMA Guides leads me to the conclusion that this Edition will continue to provoke political controversy, as has the prior publication of new editions of the Guides. It is likely there will be opposition from advocates for injured workers to any legislative modification of labor code §4660 that would force the use of the 6th Edition instead of the current 5th Edition in California.

This opposition would have been mitigated had the 6th Edition of the AMA Guides provided citations to studies that support why these reductions have been made, or provided discussions about such reductions in their textual material. Had they done so, users of their Guide could understand the rationale for the new lower level of Impairment Ratings in dozens of their tables. Absent this information, it is difficult to understand why decisions were made to lower ratings seemingly across the board. If these reductions are justified by science, it would be helpful to see the science. If they were supported by “consensus” it would be helpful to see how the AMA arrives at consensus. Instead we are left with a new Edition of the AMA Guides that substantially lowers impairment ratings in many chapters without justification or explanation given to the public.