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Assessment of disability, which includes the impact of medical impairment on future earnings capacity, is complicated where multiple impairments exist. These multiple impairments can be pre-existing or new. In a recent Med-Legal Report article in CAAAments, June 2008, entitled Combined Value Chart v. Multiple Disability Table written by Art Johnson, Esq., he discussed differences in the way multiple impairments are treated in the current vs. old PDRS and in the AMA Guides. The AMA Guides to the Evaluation of Permanent Impairment, 5th Edition (AMA, 2005) provides a methodology which will “ensure that regardless of the number of impairments, the summary value would not exceed 100% of the whole person (p. 9).”

Of particular relevance to this present article are Mr. Johnson’s comments regarding the use of vocational evidence to address what he terms the “additive” or “synergistic” effect of multiple impairments on disability and earning capacity. In his article, Johnson wrote:
“…Use vocational evidence to prove what we used to prove under paragraph 6 of the MDT (Multiple Disabilities Table), that the complete picture of combined multiple disabilities and the complete picture of loss of earning capacity, produces a rating that is greater than produced by the Combined Value chart. Have the vocational expert testify that he is not rebutting the AMA Guides Impairment formulation, by [sic] only the compressive effect of the combined value chart and that in actual fact there is no compressive effect to the combined "impairments" when they are translated into combined "disability".

…..The latest evidence from the administrative director is that the disabilities with the lowest return to work rates are those where there are multiple disabilities involve two or more body parts. Since the new rating schedule is fundamentally based now on the standard of "diminished future earning capacity", if the empirical studies by the administrative director actually show that combined disabilities have a synergistic effect on a person's loss of ability to work and cause a greater diminished future earning capacity than simply adding the disabilities, then it would behoove us to use the administrative director's own studies to show that combined ratings should not be compressed under the CVC, but they should be added, or they should be combined in a synergistic effect.

By way of review, per SB 899, the Schedule for Rating Permanent Disabilities (California Division of Workers' Compensation, 2005) was developed as required by Labor Code section 4660. The Schedule includes an adjustment for diminished future earning capacity (DFEC) that is designed to increase the permanent disability rating because of diminished future earning capacity caused by the work injury. The existing DFEC adjustment factor varies from 10% to 40% according to injury category with the lowest adjustment factor being applied to hand, finger, and vision injuries having the lowest adjustments and the highest adjustment being applied to hearing and psychiatric impairments. The Schedule is currently under review with modifications to the DFEC factors having recently been proposed by the DWC.

This author has published two prior papers on his SEDEC diminished future earnings capacity methodology: “Determining Diminished Earning Capacity in the California Workers' Compensation Program: The "SEDEC" Method,” and "New" Role for Vocational Rehabilitation in the California Workers' Compensation System: A Comprehensive Vocational Rehabilitiation Evaluation.” This article proposes that a natural extension of the SEDEC methodology can provide the vocational and earnings capacity analysis of multiple impairments suggested by Mr. Johnson in his article.

For Dr. Hall’s article, “The New PDRS and the Determination of DFEC,”
click here.

For Dr. Hall’s article, “Determining Diminished
Earning Capacity in the
California Workers'
Compensation Program:
The "SEDEC" Method,”
click here.

For Dr. Hall’s article, “The "New" Role for Vocational Rehabilitation in the California Workers' Compensation System: A Comprehensive Vocational Rehabilitiation Evaluation,” click here.

The Need to Distinguish Between Impairment, Functional Capacity, and Disability

Absolutely critical to the analysis of multiple impairments in relationship to DFEC is the role of functional capacities. Without translation of medical impairments into statements of functional capacities, the “additive” or “synergistic” effect of multiple impairments, as discussed by Johnson, cannot be determined, at least as to how they might impact employability and future earnings capacity.

As is now well understood, SB 899 mandated use of the .A.M.A. Guides to the Evaluation of Permanent Impairment, 5th Edition. As discussed in the Guides, they cannot be used to make direct estimates of “work disability”, but are intended for more general use as an estimate of “whole person impairment” and an “individual’s overall ability to perform activities of daily living”. The Guides do describe a process for determining functional limitations or “work restrictions”, i.e. what a worker can and cannot do and how activity might aggravate the medical condition.

Obtaining credible opinions regarding functional capacity as a basis for DFEC opinions is challenging. Multiple opinions often exist from various doctors, provided at different times, and often somewhat dated. Functional capacity testing can be conducted as a useful tool, but there are questions regarding reliability and validity that need to be considered in their use and should probably be conducted as part of a physician’s evaluation, not as a standalone tool.

Issues involved with determining residual functional capacity (RFC) are discussed in an excellent article entitled Impairment Rating and Disability Determination by Edward B Holmes, MD, MPH. In this article, Dr. Holmes states the following:

“How does the physician evaluating functional ability determine which recommendation to follow? In this process, the evaluating physician reviews all the information regarding credibility listed above and then compares that information with the opinions of other physicians in the file. Other sources of opinion might include evidence from chiropractors, physical therapists, optometrists, and other medical professionals. Such sources can be valuable in determining the true extent of limitations and can thereby assist in the overall credibility determination.

In general, when differing opinions about function are in the file, the opinion that is the most consistent with the evidence should be the one that is given the greatest amount of consideration. Other factors to consider when determining which source opinion to support include the following:

Examining sources – The opinions of practitioners who have examined the patient are given greater weight than the opinions of those who have not (e.g., insurance company file reviews).

Treating sources rather than providers of 1-time examinations - In general, a medical provider with a long-standing relationship may be more familiar with the patient's limitations than would a consultant who has seen the patient once.

Supporting evidence – A source that provides supporting evidence to substantiate the opinion about functional ability should be given more weight than should a source that does not have supporting evidence.

Consistency with the record - Obviously, opinions most consistent with the preponderance of evidence are given greater weight.

Medical specialty – The opinion of a specialist in the field may be given greater weight than would that of a generalist, even if the length of treatment by the specialist was much less. Furthermore, the opinion of a physician who is more familiar with the demands and tasks in the workplace is likely to be given greater weight than would the opinion of a physician who is unaware of such demands.

Many sources write opinions, such as light duty, moderate lifting, or sedentary work. These generalized, nonspecific statements of functional ability are inherently unreliable and meaningless in making appropriate ability statements. The definition of light work or sedentary work is not consistent among physicians. Further confusion can come when a treating physician writes a note in the file stating the patient is disabled. No specific level of impairment that is known by all physicians is equated with the term "disabled." To one physician, a patient's inability to lift more than 50 lb may suggest a disability. To another examining physician, this same patient may be regarded as capable of performing the essential functions of his/her current job.

The important thing to remember is that the opinion of the physician who knows the patient best and who has the most knowledge about the specific limiting condition should be carefully considered in a functional evaluation and should be integrated with an understanding of the claimant's work environment. If the treating physician makes a generalization regarding the patient's functional ability, further contact with the physician may be required to clarify the patient's specific functional restrictions and true residual capacity. The relative weight to be given to various factors should be addressed in the report, giving the specific reasons why more consideration was given to one opinion over another.

The experienced clinician can make the appropriate objective medical assessment of the patient and then consider all of the factors of credibility, weigh the source opinions, and make a final determination of the patient's functional ability”.

The A.M.A. Guides and the A.M.A.’s Disability Evaluation, 2nd Edition identify the larger issues surrounding determination of “disability” and “earning capacity”.

These factors are listed as follows:
• an individual’s age, education, acquired skills, knowledge, and work performance;
• an individual’s motivation and adaptation to change;
• work requirements;
• work environment;
• state of the job market;
• local economic conditions;
• past earnings and future potential earnings.

I propose that this list be expanded to include RFC determination, including RFC as would relate to prior or pre-existing medical impairments and their impacts on an individual’s ability to work.

I propose that this list be expanded to include RFC determination, including RFC as would relate to prior or pre-existing medical impairments and their impacts on an individual’s ability to work.

Disability Data

There exists for persons with multiple disabling impairments a combined, interactive effect that negatively impacts employment rates. In his article, Johnson discusses the DWC research. [Return-to-Work Rates for Injured Workers with Permanent Disability (January, 2007) Division of Workers’ Compensation, State of California] showing that persons with multiple impairments suffer greater impact with regard to return-to-work outcomes (DWC, 2007). Other disability and employment research from the U.S. Bureau of the Census generally supports this concept. In the Census data, persons with disability in one domain, either physical, mental, or communication, have average employment rates of 61.3%, persons with disabilities in two domains, 51.5%, and persons with disabilities in all three domains have employment rates of 31.8% . [Steinmetz, Erica, J. (2002). Americans with Disabilities: 2002. U.S. Census Bureau.]


Strategies for Dealing with Multiple Impairments
and DFEC Analysis

As stated in prior papers by this author, per the A.M.A., the role of the “Vocational Rehabilitationist” consultant (VRC) is to “bridge the gap” between “work limitations” and “disability” as reflected in diminished employability and earning capacity. In order to form opinions regarding employability and diminished future earning capacity, the VRC must sequentially evaluate an individual in terms of what they can offer a potential employer. Readers can refer to this author’s prior articles regarding the overall comprehensive vocational evaluation process as it relates to DFEC. However, in summary, the determination of DFEC requires a VRC who can carefully evaluate the residual impact of mental and/or physical work limitations upon an individual’s ability to utilize their global skills and abilities and perform specific occupations and work tasks in a specific labor market. A comprehensive vocational rehabilitation evaluation is required to do this.

To appropriately address the multiple impairments issue, a truly sequential or “layered” analysis is required. For example, a Roofer with a back injury may have a “no heavy work” restriction that can be analyzed in a straightforward manner through transferable skills analysis (TSA) to determine other forms of work they could potentially perform. However, if this worker had also been hit in the head in their accident and now has residual balance and memory problems, the DFEC analysis takes quite a different turn. Logically, workers who are already limited physically in strength, range of motion, and stamina (typical for a back injury) who also have balance and memory issues (typical of a head injury) have greater restrictions on the type and nature of work they can perform, i.e. reduced employability.

Analysis of the above worker’s situation can be hypothetically analyzed as follows:

  1. Analyze the worker with the back injury residuals alone;
  2. Analyze the worker with the head injury residuals alone;
  3. Analyze the worker with the combined effects of both the back injury and the head injury.

The result of this kind of “step by step” analysis for a Roofer would yield fairly dramatic results, both with regard to employability as well as earning capacity. Roofers typically have limited formal education and other skills and, if physically limited to “light work” type occupations, suffer substantial loss of employability and earnings, at least in the short term, but could largely reestablish their earning capacity over time assuming they can acquire new skills in a lighter occupation, such as Truck Driver. However, assuming that head injury residuals exist impacting memory, concentration, new learning, and stamina (all occupationally researchable) the effect on employment and earnings potential is magnified, both by the additional barriers/limitations posed by the head injury residuals, but also the combined and interactive effects of the physical and cognitive limitations.

The above kind of analyses can be objectively conducted with computerized occupational information systems that use standardized government data, empirically derived, that describe the demands of occupations. Systems based upon the old Dictionary of Occupational Titles (over 12,000 occupations) break occupations down by over 60 factors. The most current database available, the O*NET, analyzes fewer than 1,000 broad occupational groups, but analyzes them on over 250 factors and is especially helpful for analyzing the cognitive, behavioral, and environmental characteristics of occupations.


Do these combined work limitations always translate into reductions in earning capacity? This is often the case, but not always. It really depends upon the individual’s residual functional capacities, their employment skill set, and the relative demand for those skills. Substitute “Network Administrator” (who has received the same injuries in a work-related car accident) for the “Roofer” above and you can see that it is not quite so clear what the impact of work impairment on employability and future earnings capacity might be.

Another issue has to do with the consideration of pre-existing medical issues and impairments. A discussion of the legal issues around apportionment to pre-existing medical issues is beyond the scope of this article, but pre-existing impairment can obviously impact opinions regarding RFC, employability, and earning capacity. The above type of analysis can be conducted (and are routinely conducted in other jurisdictions such as in personal injury cases) to parse out the impact of pre-existing impairments on employability and earnings capacity issues.

To appropriately address the multiple impairments issue, a truly sequential or “layered” analysis is required.

Dr. Robert Hall has practiced as a Vocational Rehabilitation consultant in California since 1980.
He has served as Director of the Work & Health Technologies Center at San Diego State University
and as Adjunct Professor in SDSU’s graduate Rehabilitation Counseling Program since 1993.
Dr. Hall has conducted extensive research and training activities in disability, rehabilitation, and return-to-work programs. Dr. Hall has consulted
with and provided training to a variety of health
and human service organizations in the areas of rehabilitation program development & evaluation.

Robert Hall, Ph.D.
Certified Rehabilitation Counselor
Certified Disability Management Specialist
Hall Associates
7290 Navajo Rd. #105
San Diego, Ca. 92119
Phone: (619) 463-9334
Fax: (619) 463-9337


For a detailed CV,
click here.
Multiple Impairments and
Their Impact on the DFEC Analysis
by Robert Hall, Ph.D., CRC, CDMS

Robert B.Hall, Ph.D., is a vocational rehabilitation professional, consultant, and teacher who created the “SEDEC” method of analyzing diminished future earning capacity [DFEC].
> The Doctor's Office: Chiropractic
> Multiple Impairments & DFEC
> Defense Perspective: EAMS
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Getting on Top of ToDos
> Carving up PD: Part II