Erroneous Rating Causes

The goal of the Guides is to provide consistent ratings, therefore reducing conflict. The Guides state “Two physicians, following the methods of the Guides to evaluate the same patient, should report similar results and reach similar conclusions.” (AMA Guides, p. 17) Yet, review of this data reveals that this is often not achieved.

There are many cases of erroneous ratings, including bias, differences in clinical and causation assessment, and misapplication of Guides criteria, either through lack of knowledge and skills in rating impairment or intent. The nature of the errors is such that most erroneous ratings will be higher, rather than lower. Most medical schools and residency training programs do not include instruction on the assessment of impairment, disability, or causation. Therefore many physicians lack an adequate ability to assess these and other medicolegal issues.

The principles of assessing impairment are provided in Chapters 1 and 2, however it appears that often physicians have not become familiar with the rules presented in these chapters, and rather focus their attention on chapters specific to the region they are rating. Chapter 2, Practical Application of the Guides, is a particularly important chapter, not only for rating physicians, but also for attorneys. This chapter specifies rules and standards for the impairment evaluation. It also provides superb content for an effective cross-examination of a physician who has performed an erroneous rating. Section 2.1 defines impairment evaluations, Section 2.2 discusses who performs impairment evaluations, Section 2.3 identifies the roles and responsibilities of the examiner, Section 2.4 explains when ratings are performed, Section 2.5 provides critical rules for the evaluation, and Section 2.6 outlines standards for reports. Failure to follow the defined procedures will result in an erroneous report. Section 2.6 Preparing Reports provides detailed standards for reports. Failure to follow these standards will result in a questionable report and rating.

The rating physician must be “independent and unbiased”. This can be challenging for any evaluator, however it is more likely to be problematic for the treating physician since there is an inherent patient advocacy role. (Barth RJ, Brigham CR, Who is in the better position to evaluate, the treating physician or an independent examiner?, Guides Newsletter, November – December 2005). The Guides state on page 18 “An impairment evaluation is a medical evaluation performed by a physician, using a standard method as outlined in the Guides to determine permanent impairment associated with a medical condition. . . .The physician’s role in performing an impairment evaluation is to provide an independent, unbiased assessment of the individual’s medical condition, including its effect on function, and identify abilities and limitations to performing activities of daily living as listed in Table 1-2.”

A skilled independent medical evaluator typically spends more time with a patient than a treating physician at a single visit, and therefore may obtain clinical information not known to the treating physician. It is probable that the treating physician will not consider alternative or new diagnoses at the time of rating. It is possible that the treating physician will causally relate problems to an injury if this appears advantageous to the patient and/or the physician. For example, if a treating physician receives referrals from plaintiff counsel it is not unexpected that this physician will causally relate problems to the defined injury and may inflate a rating. A treating physician caring for a patient in a managed care situation may be more likely relate a problem to an injury if this provides an additional source of revenue. The treatment role may influence when the physician defines maximal medical improvement (MMI), i.e. at discharge from care the physician may be inclined to define the patient as ratable, even though it is probable that the patient is not yet at MMI. A treating physician may want to increase a rating, particularly if the impairment number does not appear to reflect a level of perceived disability.

There are many potential rating errors resulting from inaccurate clinical or causation analysis. These include inappropriate diagnosis, rating prior to being at maximal medical improvement, using unreliable examination findings, not considering what is normal for the individual, and inaccurate causation assessment.

Incorrect clinical assessment can result in the rating of impairment for a condition that is not present or unrelated to the alleged injury. For example, the physician may label a patient as having “complex regional pain syndrome” (CRPS) and rate for this disorder, whereas the more accurate diagnosis is “somatization.” In the Guides certain diagnoses are not typically associated with ratable impairment, i.e. tendonitis or psychiatric illness; a physician attempting to inflate a rating may choose to provide another diagnostic label that would result in ratable impairment.

Assessing impairment prematurely will often result in an inflated impairment rating. The rating of permanent impairment cannot occur until the patient has achieved maximal medical improvement (MMI). MMI is defined on page 601 as “a condition or state that is well stabilized and unlikely to change substantially in the next year, with or without medical treatment.” Typically following an injury a patient will improve over time, improved range of motion and neurological function and resolution of ratable findings will result in a lower impairment rating. MMI is often not achieved until a minimum of six months to one year post injury. Cases that often require a longer time frame for resolution include carpal tunnel syndrome with ongoing neurological deficits, hand injuries, and head injuries.

An erroneous rating will occur if the rating is based on clinical findings that are erroneous. Findings must be reproducible if they are to serve as a basis for impairment rating. The Guides state in Section 2.5d on page 20:

Two measurements made by the same examiner using the Guides that involve an individual or an individual’s function would be considered consistent if they fall within 10% of each other. Measurements should be consistent between two trained examiners or by one observer on two separate occasions, assuming the individual’s condition is stable.

Many clinical findings are not totally objective, i.e. independent of the examinee. For example, with range of motion impairment rating, the rating is based on findings of active motion, i.e. what the individual demonstrates. An individual may display less range of motion than actual capability. Neurological findings, such as reports of diminished sensation, are dependent on self report and an individual may demonstrate less strength than true capability. In that an individual can demonstrate less capability then they are truly capable of, however cannot demonstrate greater capability than this limit, inconsistent examination findings will nearly always result in greater impairment. Examiners vary in their clinical examination skills; therefore there may be a lack of reliability in demonstrating clinical findings.

The musculoskeletal chapters (Chapters 15 to 17) define standards for consistency. For example, in Chapter 15, The Spine, there is a lengthy discussion of process of obtaining spinal range-of-motion measurements using an inclinometer. Section 15.8a, General ROM Method Measurement Principles, on page 399 provides emphasis with italics.

Using the spine as an example, there are other findings that may not be reliable; including “spasm”, “guarding”, “non-verifiable radicular complaints” and neurological findings. It may be advantageous for physicians wanting to demonstrate the need for ongoing treatment to report findings that may not be observed by others. In reviewing a report it is imperative to determine whether the examination findings were reliable. This includes assessing whether the physician has performed the examination to determine the presence of consistent findings and comparing examination findings to other observations since the patient has been at maximal medical improvement; other sources of data may include physician records, physical therapy records, and surveillance.

Another common error is not considering what is normal for the individual. The Fifth Edition discusses in Section 1.2a Impairment the determination of normal. The Guides state on page 2 “when evaluating an individual, a physician has two options: consider the individual’s health preinjury or preillness state or the condition of the unaffected side as “normal” for the individual if this is known, or compare that individual to a normal value defined by population averages of healthy people. The Guides uses both approaches.” Section 16.4c Method for Motion Impairment Calculation states on page 453 “The measurements reported in the impairment tables and pie charts reflect the accepted average range(s) of motion for each joint. However, certain people can have either lesser or greater joint flexibility than average. It is therefore most important to always compare measurements of the relevant joint(s) in both extremities. If a contralateral “normal” joint has a less than average mobility, the impairment value(s) corresponding to the uninvolved joint can serve as a baseline and are subtracted from the calculated impairment for the involved joint. The rationale for this decision should be explained in the report.” In this case the opposite extremity does serve as “normal” for this individual, therefore losses should be determined in relationship to this normal. Extremity evaluations should always include examination of both sides.

In assessing impairment it is necessary to distinguish what impairment is related to the alleged injury as opposed to impairment that may be due to other injury, degenerative disease, or illness. The premise of causation is that a given cause (A) and a given effect (B) are associated within a reasonable degree of medical probability. If the practitioner promotes the premise that, "within a reasonable degree of medical probability (A) & (B) are causally related," all three of the following separate notions are assumed to be correct (medically probable):

Once it has been established that both (A) and (B) are probable, then there must also be a probable relationship established between the two, before a final positive causality conclusion can be promulgated. A conclusion that a cause did contribute to an effect or impairment must rely on the documentation of circumstances that were present and verification that the type and magnitude of the factors were sufficient and bore the necessary temporal relationship to the condition. Many ratings of impairment lack this critical analysis.

Causation analysis is the critical first step to apportionment analysis. Impairment may be related to multiple causes. Section 2.5h Changes in Impairment from Prior Ratings on page 21 provides a discussion of the Guides approach to apportionment. The Guides state:

In reviewing a case it is imperative to assure that clinical and causation assessments were accurate, that the rating was performed when at maximal medical improvement, that examination findings were consistent, and what was normal for the individual was determined. An unreliable examination will result in an erroneous rating, and nearly always this erroneous rating will be higher than is appropriate.

The Guides criteria must be applied appropriately. Section 2.5b Combining Impairment Ratings explains “Begin with an estimate of the individual’s most significant (primary) impairment and evaluate other impairments in relation to it. Related but separate conditions are rated separately and impairment ratings are combined unless criteria for the second impairments are included in the primary impairment.” It is important to assure that the impairment is adequately rated without duplicative rating, i.e. “double dipping”.

Spinal impairment ratings are often erroneous. Common errors include basing the data on unreliable data, using the wrong method, misapplying a method, and rating for non-existent corticospinal tract damage. Chapter 15, The Spine, explains there are two methods, the Diagnosis-Related Estimates (DRE) Method and the Range-of-Motion (ROM) Method, and three spinal regions, cervical, thoracic, and lumbar. The Fifth Edition states in Section 15.2, Determining the Appropriate Method for Assessment on page 379 “The DRE method is the principal methodology used to evaluate an individual who has had a distinct injury”. Typically, the ROM Method will result in a higher rating than the DRE Method, with the notable exception of spinal fusions. (With spinal fusions, a single-level fusion is rated using the DRE Method and typically this results in a higher rating than with a multiple-level fusion that is rated using the ROM Method.) A common inappropriate excuse for this is multiple level degenerative disease, a finding associated with aging and genetics. Section 15.2 Determining the Appropriate Method for Assessment (379-381) stipulates specific situations when the ROM method is used. It is used if there is radiculopathy at multiple levels, however not merely on the basis of degenerative changes. The Guides explains on page 383:

Therefore, first determine if the appropriate method was applied. Once the appropriate method is selected, it is important to determine the correct rating based on reliable examination findings. The Guides provide detailed standards for the physical examination in Section 15.1 Principles of Assessment (374-378) and for assessing motion in Section 15.8 Range-of-Motion Method (398-403); this is also excellent content for cross-examination. If the Diagnosis-Related Estimates (DRE) Method is used, the physician must select one of five categories based on specific, reliable findings and within each category choose an appropriate numeric rating within a 3% range. A common error is to assign a patient to the wrong category. With the Range-of-Motion Method, a rating is based on the combination of impairments assigned to specific disorders, range of motion assessed by an inclinometer, and neurological deficit. Each of these components is fraught with potential error.

Upper extremity joint disorders and neurological problems, such as carpal tunnel syndrome, are rated using Chapter 16, The Upper Extremities. Common errors include: failing to perform an appropriate assessment as explained in Section 16.1 Principles of Assessment (434-441), not using the opposite uninjured extremity as normal for that individual, erroneous sensory impairment assessment for carpal tunnel syndrome, rating for non-verifiable complex regional pain syndrome, rating for tendinitis, and including grip strength in the rating. The Guides state in Section 16.8 Strength Evaluation on page 508 “Decreased strength cannot be rated in the presence of decreased motion, painful conditions, deformities, or absence of parts (eg, thumb amputation) that prevent effective application of maximal force in the region being evaluated.”

The most common problem associated with the use of Chapter 17, The Lower Extremities is combining multiple duplicative impairments. There are thirteen approaches to assessing lower extremity impairment and as noted on page 527 “Typically, one method will adequately characterize the impairment and its impact on the ability to perform ADL (activities of daily living).” Other common problems are inappropriate rating for gait derangement or muscle strength loss, and rating for arthritis that is associated with aging rather than the injury.

Chapter 18, Pain provides information on the evaluation and rating of pain. Pain may be rated qualitatively and in certain unusual circumstances incremental impairment of up to 3% whole person permanent impairment may be given. Any rating for pain should be reviewed to determine if it is appropriate. There is no ratable impairment for controversial or ambiguous disorders such as myofascial pain syndrome, fibromyalgia, and “disputed neurogenic” thoracic outlet syndrome.

The reasons for erroneous ratings are multifold.