AMA Guides

618 Pages·2001·3.35 MB·English

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Philosophy, Purpose, and
Appropriate Use of the Guides
1.1 History
1.2 Impairment, Disability, and Handicap
1.3 The Organ System and Whole Body
Approach to Impairment
1.4 Philosophy and Use of the Combined
Values Chart
1.5 Incorporating Science with Clinical
Judgment
1.1 History
1.6 Causation, Apportionment Analysis,
and Aggravation The Guides was first published in book form in 1971
in response to a public need for a standardized,
1.7 Use of theGuides objective approach to evaluating medical impair-
ments. Sections of the first edition of the Guides
1.8 Impairment Evaluations in Workers’ were originally published in the Journal of the
Compensation American Medical Association,beginning in 1958
and continuing until August 1970.1Since then,the
1.9 Employability Determinations Guideshas undergone four revisions,culminating in
the current,fifth edition. The purpose of this fifth
1.10Railroad and Maritime Workers edition of the Guidesis to update the diagnostic cri-
teria and evaluation process used in impairment
1.11The Physician’s Role Based on the assessment,incorporating available scientific evi-
Americans with Disabilities Act (ADA) dence and prevailing medical opinion. Chapter
authors were encouraged to use the latest scientific
1.12Summary evidence from their specialty and,where evidence
was lacking,develop a consensus view. This chapter
was revised from the earlier edition in response to
specific requests from user groups concerning the
definitions,appropriate use,and scope of application
of the Guides.
1
2 Guides to the Evaluation of Permanent Impairment
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C The fifth edition includes most of the common con- Table 1-1,adapted from a report by the AMA
ditions,excluding unusual cases that require individ- Council on Scientific Affairs,lists various definitions
ual consideration. Since this edition encompasses the of impairment and disability used by four main
most current criteria and procedures for impairment authorities:the AMA Guides,the World Health
assessment,it is strongly recommended that physi- Organization,the Social Security Administration,
cians use this latest edition,the fifth edition,when and a state workers’compensation statute.4Although
rating impairment. a nationally accepted definition for impairment does
not exist,the general concept of impairment is simi-
lar in the definitions of most organizations. Several
1.2 Impairment, terms used in the AMA definition,and their applica-
tion throughout the Guides,will be discussed in this
Disability, and
chapter and Chapter 2.
Handicap
Loss,loss of use,or derangement implies a change
from a normal or “preexisting”state. Normalis a
1.2a Impairment range or zone representing healthy functioning and
The Guidescontinues to define impairmentas varies with age,gender,and other factors such as
“a loss,loss of use,or derangement of any body environmental conditions. For example,normal heart
part,organ system,or organ function.”2This defi- rate varies between a child and adult and according
nition of impairment is retained in this edition. A to whether the person is at rest or exercising.
medical impairment can develop from an illness or Multiple factors need to be considered when assess-
injury. An impairment is considered permanent when ing whether a specific or overall function is normal.
it has reached maximal medical improvement A normal value can be defined from an individual or
(MMI),meaning it is well stabilized and unlikely to population perspective.
change substantially in the next year with or without
medical treatment.The term impairmentin the When evaluating an individual,a physician has two
Guides refers to permanent impairment,which is options:consider the individual’s healthy preinjury
the focus of the Guides. or preillness state or the condition of the unaffected
side as “normal”for the individual if this is known,
An impairment can be manifested objectively,for or compare that individual to a normal value defined
example,by a fracture,and/or subjectively,through by population averages of healthy people. The
fatigue and pain.3Although the Guidesemphasizes Guidesuses both approaches. Accepted population
objective assessment,subjective symptoms are values for conditions such as extremity range-of-
included within the diagnostic criteria. According to motion or lung function are listed in the Guides; it is
the Guides,determining whether an injury or illness recommended that the physician use those values as
results in a permanent impairment requires a medical detailed in the Guides when applicable. In other cir-
assessment performed by a physician. An impair- cumstances,for instance,where population values
ment may lead to functional limitations or the inabil- are not available,the physician should use clinical
ity to perform activities of daily living. judgment regarding normal structure and function
and estimate what is normal for the individual based
on the physician’s knowledge or estimate of the indi-
vidual’s preinjury or preillness condition.
Philosophy,Purpose,and Appropriate Use of the Guides 3
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Table 1-1Definitions and Interpretations of Impairment and Disability
Organization Impairment Disability Physicians’ Role Comments
Guides to the Evaluation A loss, loss of use, or An alteration of an Determine impairment, An impaired individual
of Permanent Impairment derangement of any body individual’s capacity to provide medical informa- may or may not have a
(5th ed, 2000) part, organ system, or meet personal, social, or tion to assist in disability disability.
organ function. occupational demands determination.
because of an impairment.
World Health Problems in body function Activity limitation Not specifically defined; Emphasis is on the
Organization (WHO) or structure as a signifi- (formerly disability) is a assumed to be one of the importance of functional
(1999) cant deviation or loss. difficulty in the perform- decision-makers in deter- abilities and defining
Impairments of structure ance, accomplishment, or mining disability through context-related activity
can involve an anomaly, completion of an activity impairment assessment. limitations.
defect, loss, or other sig- at the level of the person.
nificant deviation in body Difficulty encompasses all
structures. of the ways in which the
doing of the activity may
be affected.
Social Security An anatomical, physiolog- The inability to engage in Determine impairment; Physicians and nonphysi-
Administration (SSA) ical, or psychological any substantial, gainful may assist with the dis- cians need to work
(1995) abnormality that can be activity by reason of any ability determination as a together to define situa-
shown by medically medically determinable consultative examiner. tional disabilities.
acceptable clinical and physical or mental impair-
laboratory diagnostic ment(s), which can be
techniques. expected to result in
death or which has lasted
or can be expected to last
for a continuous period of
not less than 12 months.
State Workers’ “Permanent impairment” “Temporary disability” “Evaluation (rating) of Purpose is to provide sure
Compensation Law is any anatomic or func- means a decrease in permanent impairment” is and certain relief to those
(typical)5 tional loss after maximal wage-earning capacity a medical appraisal of the who become injured by
medical improvement has due to injury or occupa- nature and extent of the accident or suffer effects
been achieved and which tional disease during a injury or disease as it of disease from exposure
abnormality or loss, med- period of recovery. (Idaho affects an injured to hazards arising out of
ically, is considered stable Codesection 72-102[10] employee’s personal effi- and in the course of
or nonprogressive at the “Permanent disability” ciency in the activities of employment.
time of evaluation. results when the actual or daily living, such as self-
Permanent impairment is presumed ability to care, communication, nor-
a basic consideration in engage in gainful activity mal living postures,
the evaluation of perma- is reduced or absent ambulation, elevation,
nent disability and is a because of permanent traveling, and nonspecial-
contributing factor to, but impairment and no funda- ized activities of bodily
not necessarily an indica- mental or marked change members. (Idaho Code
tion of, the entire extent in the future can be rea- section 72-424)
of permanent disability. sonably expected. (Idaho
(Idaho Codesection Codesection 72-423)
72-422)
4 Guides to the Evaluation of Permanent Impairment
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C Data from healthy populations,when available and The impairment criteria outlined in the Guidespro-
widely referenced,are incorporated into chapters of vide a standardized method for physicians to use to
the Guides. In some organ or body systems,such as determine medical impairment. The impairment cri-
respiratory,certain measurements of lung function teria include diagnostic criteria,incorporating
have been standardized for age and gender. In other anatomic and functional measures. The impairment
body systems,such as the musculoskeletal,age and criteria were developed from scientific evidence as
gender differences are not reflected in most of the cited andfrom consensus of chapter authors or of
values. While there may be age and gender differ- medical specialty societies.
ences anticipated for some musculoskeletal values,
such as range of motion in the spine and extremities, Impairment percentagesor ratingsdeveloped by
this edition of the Guidesmainly reflects average medical specialists are consensus-derived estimates
range of motion from healthy populations of mixed that reflect the severity of the medical condition and
age and gender. The normal values presented in the the degree to which the impairment decreases an
musculoskeletal section are based on a review of individual’s ability to perform common activities of
studies measuring range of motion,as cited in the daily living (ADL),excluding work. Impairment rat-
text. Evaluating physicians may use their clinical ings were designed to reflect functional limitations
judgment,however,and comment on any significant and not disability. The whole person impairment
age or gender effect for a particular individual. For percentages listed in the Guides estimate the impact
instance,the “normal”preinjury range of motion for of the impairment on the individual’s overall ability
a gymnast with hypermobility may exceed the listed to perform activities of daily living,excluding work,
normal values. as listed in Table 1-2.
If an individual had previous measurements of func-
tion that were below or above average population
Table 1-2Activities of Daily Living Commonly Measured
values,the physician may discuss that prior value
in Activities of Daily Living (ADL) and
and any subsequent loss for the individual,as well as
Instrumental Activities of Daily Living
compare it to the population normal.For example,a
(IADL) Scales 6,7
highly functioning athlete with documented,above-
normal lung function,who has sustained an injury Activity Example
and now has decreased lung function that is nonethe-
Self-care, Urinating, defecating, brushing teeth,
less similar to population averages,has experienced personal hygiene combing hair, bathing, dressing
a loss in his or her lung function and has sustained an oneself, eating
impairment. Based only on a population comparison, Communication Writing, typing, seeing, hearing,
the athlete would be given a 0% impairment rating. speaking
However,it would be more appropriate in this Physical activity Standing, sitting, reclining, walking,
instance for the physician to assign an impairment climbing stairs
rating based on the degree of change from the ath- Sensory function Hearing, seeing, tactile feeling, tasting,
lete’s preinjury to postinjury state. smelling
Nonspecialized Grasping, lifting, tactile
In evaluating impairment,the Guidesconsiders both hand activities discrimination
anatomic and functional loss. Some chapters place a Travel Riding, driving, flying
greater emphasis on either anatomic or functional Sexual function Orgasm, ejaculation, lubrication,
loss,depending upon common practice in that spe- erection
cialty. Anatomic lossrefers to damage to the organ Sleep Restful, nocturnal sleep pattern
system or body structure,while functional lossrefers
to a change in function for the organ or body system.
An example of an anatomic deviation is development
of heart enlargement; functional loss includes a loss
in ejection fraction or the ability of the heart to pump
adequately. Anatomic loss receives greater emphasis
in the musculoskeletal system,as in measurements
such as range of motion. Functional considerations
receive greater emphasis in the mental and behav-
ioral section.
Philosophy,Purpose,and Appropriate Use of the Guides 5
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The medical judgment used to determine the original indicated in Table 1-2. A 90% to 100% WP impair- C
impairment percentages could not account for the ment indicates a very severe organ or body system
diversity or complexity of work but could account impairment requiring the individual to be fully
for daily activities common to most people. Work is dependent on others for self-care,approaching death.
not included in the clinical judgment for impairment
percentages for several reasons:(1) work involves The activities of daily living,as originally developed
many simple and complex activities; (2) work is for the Guidesin the first and second editions,1,6sig-
highly individualized,making generalizations inac- nify common activities currently represented in
curate; (3) impairment percentages are unchanged scales of Activities of Daily Living and Instrumental
for stable conditions,but work and occupations Activities of Daily Living.7The Guidesrefers to
change; and (4) impairments interact with such other common ADLs,as listed in Table 1-2. The ADLs
factors as the worker’s age,education,and prior listed in this table correspond to the activities that
work experience to determine the extent of work dis- physicians should consider when establishing a per-
ability. For example,an individual who receives a manent impairment rating. A physician can often
30% whole person impairment due to pericardial assess a person’s ability to perform ADLs based on
heart disease is considered from a clinical standpoint knowledge of the patient’s medical condition and
to have a 30% reduction in general functioning as clinical judgment. When the physician is estimating
represented by a decrease in the ability to perform a permanent impairment rating,Table 1-2 can help to
activities of daily living. For individuals who work in determine how significantly the impairment impacts
sedentary jobs,there may be no decline in their work these activities. Using the impairment criteria within
ability although their overall functioning is a class and knowing the activities the individual can
decreased. Thus,a 30% impairment rating does not perform,the physician can estimate where the indi-
correspond to a 30% reduction in work capability. vidual stands within that class.
Similarly,a manual laborer with this 30% impair-
ment rating due to pericardial disease may be com- There are many scales that measure ability to perform
pletely unable to do his or her regular job and,thus, ADLs with greater degrees of accuracy. Many of
may have a 100% work disability. these scales are concerned with more severe levels of
disability,relevant to institutionalized patients and the
As a result,impairment ratings are not intended for elderly.7During the 1970s,the ADL concept was
use as direct determinants of work disability. When a extended to consider problems experienced by those
physician is asked to evaluate work-related disability, living in the community,a field that has come to be
it is appropriate for a physician knowledgeable about termed Instrumental Activities of Daily Living
the work activities of the patient to discuss the spe- (IADL).7There is a continued effort to validate these
cific activities the worker can and cannot do,given scales; some of the more commonly utilized,vali-
the permanent impairment. dated IADL and ADL scales are listed in Table 1-3.7
Scales vary in their appropriateness for a given indi-
Most impairment percentages in this fifth edition vidual,based upon the level of impairment,body sys-
have been retained from the fourth edition because tems affected,and degree of accuracy required. Some
there are limited scientific data to support specific scales are most appropriate for an active,working
changes. It is recognized that there are limited data population; others are more suited to a chronically ill,
to support some of the previous impairment percent- disabled population. Since there is no agreed-upon
ages as well. However,these ratings are currently scale for a working population and physicians who
accepted and should not be changed arbitrarily. In use the Guidesmay evaluate different populations of
this edition,some percentages have been changed for individuals (ie,healthy or chronically ill),a physician
greater scientific accuracy or to achieve consistency may choose the most appropriate of any of the vali-
throughout the book. dated scales for a more in-depth assessment of ADL,
to obtain further information to supplement clinical
A 0% whole person (WP) impairment rating is judgment,or to gain assistance in determining where
assigned to an individual with an impairment if the an individual stands within an impairment range.
impairment has no significant organ or body system
functional consequences and does not limit theper-
formance of the common activities of daily living
6 Guides to the Evaluation of Permanent Impairment
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Table 1-3Scales for Measurement of Instrumental Activities of Daily Living (IADL)
and Activities of Daily Living (ADL)
IADL
Scale Design/Description Target Population Measures Comment
The OECD Long-Term Summary of the impact of General population • Eyesight An early attempt to
Disability ill health on essential • Hearing develop an international
Questionnaire8 activities of daily living. set of disability items;
• Speaking
European content
• Carry an object of 5 kg
for 10 meters
• Run 100 meters
• Walk 400 meters with-
out resting
• Move between rooms
• Get in and out of bed
• Dress and undress
• Cut toenails
• Bend and pick up a
shoe from floor
• Cut food
• Bite and chew hard
food
The Health Assessment Measures difficulty in Used to assess adult • Dressing and grooming Widely used instrument;
Questionnaire9 performing activities of arthritics in a wide range • Arising pays close attention to
daily living of research settings to rigorous measures
• Eating
evaluate care
• Walking
• Hygiene
• Reach
• Grip
• Outdoor activity
The Functional Assesses physical and cog- General population • Self-care Based on the Barthel
Independence Measure10 nitive disability, monitors index
• Sphincter control
patient progress, and
assesses outcomes of • Mobility
rehabilitation
• Locomotion
• Communication
• Social cognition
ADL
The Barthel Index Measures functional inde- Used in patients with Ten-item version Measures what a patient
(Formerly the Maryland pendence in personal care chronic conditions, before evaluates: does; widely applied
Disability Index)11 and mobility; completed and after treatment • Feeding
by health professionals
• Moving from wheel-
chair to bed and return
• Personal toilet
• Gettingonandofftoilet
• Bathing self
• Mobility
• Ascending and
descending stairs
• Dressing
• Controlling bowels
• Controlling bladder
Philosophy,Purpose,and Appropriate Use of the Guides 7
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Scale Description Target Population Measures Comment
The Index of Describes primary biologi- Originally developed for Assesses independence in Widely used with children
Independence in cal and psychosocial func- elderly and chronically ill six activities: and adults, with the
Activities of Daily tion; limited information patients with strokes and • Bathing mentally retarded and
Living12 on ambulation fractured hips the physically disabled,
• Dressing
in the community and
• Toileting institutions
• Transferring from bed
to chair
• Continence
• Feeding
The Functional Status Based on a method devel- Rehabilitation patients • Functional Status in
Rating System13 oped to provide national Self-Care(eating/feed-
statistics on hospital uti- ing, personal hygiene,
lization and treatment toileting, bathing,
outcomes bowel/bladder/skin
management, bed
activities, dressing)
• Functional Status in
Mobility(transfers,
wheelchair skills, ambu-
lation, stairs, commu-
nity mobility)
• Functional Status in
Communication(read-
ing, talking, motor com-
munication,written
languageexpression)
• Functional Status in
Psychosocial
Adjustment
(emotional adjustment,
social support, adjust-
ment to limitations)
• Functional Status in
Cognitive Function
(attention span, judg-
ment, reasoning,
memory)
The OARS A combined 7 ADL and 7 General population, espe- • Individual functioning Flexible instrument, reli-
Multidimensional IADL scale that covers cially elderly (basic demographics, able, and valid ADL and
Functional Assessment functional and services social, economic IADL sections
Questionnaire14 assessment resources)
• Mental health
• Physical health
• ADL
• Services assessment
(transportation,
social/recreational)
The Medical Outcomes An extended ADL scale General population • Vigorous activities Recognizes differences in
Study Physical that is sensitive to varia- (running, lifting heavy people’s values regarding
Functioning Measure15 tions at relatively high lev- objects, strenuous functional ability by
els of physical function sports) including a question on
• Moderate activities satisfaction with physical
(moving a table, push- performance
ing a vacuum cleaner,
bowling, playing golf)
• Lifting or carrying
groceries
• Climbing severalflights
of stairs
• Climbing oneflight of
stairs
• Bending, kneeling, or
stooping
• Walking more than one
mile
• Walking several blocks
• Walking one block
• Bathing or dressing self
8 Guides to the Evaluation of Permanent Impairment
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C 1.2b Disability The Guidescontinues to define disability as an
The term disabilityhas historically referred to a alteration of an individual’s capacity to meet per-
broad category of individuals with diverse limitations sonal,social,or occupational demands or statu-
in the ability to meet social or occupational demands. tory or regulatory requirements because of an
However,it is more accurate to refer to the specific impairment.2An individual can have a disability in
activity or role the “disabled”individual is unable to performing a specific work activity but not have a
perform. Several organizations are moving away disability in any other social role.2Physicians have
from the term disabilityand instead are referring to the education and training to evaluate a person’s
specific activity limitationsto encourage an emphasis health status and determine the presence or absence
on the specific activities the individual can perform of an impairment. If the physician has the expertise
and to identify how the environment can be altered and is well acquainted with the individual’s activities
to enable the individual to perform the activities and needs,the physician may also express an opinion
associated with various social or occupational roles. about the presence or absence of a specific disability.
(Table 1-1).4 For example,an occupational medicine physician
who understands the job requirements in a particular
According to a 1997 Institute of Medicine Report, workplace can provide insights on how the impair-
“disability is a relational outcome,reflecting the ment could contribute to a workplace disability.
individual’s capacity to perform a specific task or
activity,contingent on theenvironmental conditions The impairment evaluation,however,is only one
in which they are to be performed.”16Disability is aspect of disability determination. A disability deter-
context-specific,not inherent in the individual,but a mination also includes information about the individ-
function of the interaction of the individual and the ual’s skills,education,job history,adaptability,age,
environment. and environment requirements and modifications.3
Assessing these factors can provide a more realistic
The World Health Organization (WHO) is revising its picture of the effects of the impairment on the ability
1980 International Classification of Impairments, to perform complex work and social activities. If
Disabilities and Handicapsand has released a draft adaptations can be made to the environment,the
document,The International Classification of individual may not be disabled from performing that
Impairments,Activities and Participation (ICIDH-2).17 activity.
The term disabilityhas been replaced by a neutral
term,activity,and limits in ability are described as
activity limitations. The change in terminology arose
for several reasons:to choose terminology without an
associated stigma,to avoid labeling,and to emphasize
the person’s residual ability. Representatives world-
wide are reviewing this international classification
scale of impairments,function,and activities.
Figure 1-1 The Relationship Among the Concepts of Normal Health,Impairment,Functional Limitation,and Activity
Disability (Performance Limitation)
Disability
Normal Health Impairment Functional Limitation
(loss, loss of (limit in the ability to
use, derangement perform basic activities No Disability
of body part, of daily living)
organ system, or
organ function)
Disability
(no accomodation available;
Normal Health Impairment Functional Limitation
unable to work as a stock clerk)
(eg, healthy back) (eg, disk (eg, unable to lift 45 kg
herniation L5/S1, [100 lb]) No Disability
decreased range (mechanical lift available;
of motion) able to operate lift; can work
as a stock clerk)
Philosophy,Purpose,and Appropriate Use of the Guides 9
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1.3 The Organ System h
As discussed in this chapter and illustrated in Figure C
1-1,medical impairments are not related to disability and Whole Body
in a linear fashion. An individual with a medical
Approach to
impairment can have no disability for some occupa-
tions,yet be very disabled for others. For example, Impairment
severe degenerative disk disease may impair the
functioning of the spine of both a licensed practical
nurse and a bank president in a similar fashion when The Guidesimpairment ratings reflect the severity
performing their activities of daily living. However, and limitations of the organ/body system impairment
in terms of occupation,the bank president is less and resulting functional limitations.Most
likely to be disabled by this impairment than the organ/body systems chapters in the Guides provide
licensed practical nurse.An individual who develops impairment ratings that represent the extent of whole
rheumatoid arthritis may be disabled from work as a person impairment. In addition to listing whole per-
tailor but may be able to work as a child care aide. A son impairments,the musculoskeletal chapters pro-
pilot who develops a visual impairment,correctable vide regional impairment ratings (eg,upper extremity,
with glasses,may be able to perform all of his daily lower extremity); regional ratings are then converted
activities but is no longer able to fly a commercial into whole person impairment ratings. Within some
plane. An individual with repeated hernias and musculoskeletal regions,a consensus group devel-
repairs may no longer be able to lift more than opedweights to reflect the relative importance of
20 kg (40 lb) but could work in a factory where certain regions. For example,different fingers or dif-
mechanical lifts are available. ferent areas of the spine are given different weights,
representing their unique and relative importance to
The Guidesis not intended to be used for direct the region’s overall functioning. These weights,
estimates of work disability. Impairment percentages which have gained acceptance in clinical practice,
derived according to the Guidescriteria do not have been retained to enable regulatory authorities to
measure work disability. Therefore,it is inappropri- convert from a regional body to whole person impair-
ate to use the Guides’criteria or ratings to make ment when needed.
direct estimates of work disability.
1.2c Handicap 1.4 Philosophy and Use
Handicapis a term historically used in both a legal
of the Combined
and a policy context to describe disability or people
living with disabilities. Though the term continues to Values Chart
be used,generally it is being replaced with the pre-
ferred term disability.
The Combined Values Chart(p. 604) was designed
to enable the physician to account for the effects of
multiple impairments with a summary value. A stan-
dard formula was used to ensure that regardless of
the number of impairments,the summary value
would not exceed 100% of the whole person.
According to the formula listed in the combined val-
ues chart,multiple impairments are combined so that
the whole person impairment value is equal to or less
than the sum of all the individual impairment values.
10 Guides to the Evaluation of Permanent Impairment
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h 1.5 Incorporating
C A scientific formula has not been established to indi-
cate the best way to combine multiple impairments. Science with Clinical
Given the diversity of impairments and great vari-
Judgment
ability inherent in combining multiple impairments,
it is difficult to establish a formula that accounts for
all situations. A combination of some impairments The Guidesuses objective and scientifically based
could decrease overall functioning more than sug- data when available and references these sources.
gested by just adding the impairment ratings for the When objective data have not been identified,esti-
separate impairments (eg,blindness and inability to mates of the degree of impairment are used,based on
use both hands). When other multiple impairments clinical experience and consensus. Subjective con-
are combined,a less than additive approach may be cerns,including fatigue,difficulty in concentrating,
more appropriate. States also use different tech- and pain,when not accompanied by demonstrable
niques when combining impairments. Many work- clinical signs or other independent,measurable
ers’compensation statutescontain provisions that abnormalities,are generally not given separate
combine impairments to produce a summary rating impairment ratings. Chronic pain is discussed in
that is more than additive. Other options are to com- Chapter 18. Physicians recognize the local and dis-
bine (add,subtract,or multiply) multiple impair- tant pain that commonly accompanies many disor-
ments based upon the extent to which they affect an ders. Impairment ratings in the Guidesalready have
individual’s ability to perform activities of daily liv- accounted for commonly associated pain,including
ing. The current edition has retained the same com- that which may be experienced in areas distant to the
bined values chart,since it has become the standard specific site of pathology. For example,when a cer-
of practice in many jurisdictions. Other approaches, vical spine disorder produces radiating pain down
when published in scientific peer-reviewed literature, the arm,the arm pain,which is commonly seen,
will be evaluated for future editions. has been accounted for in the cervical spine impair-
ment rating.
In general,impairment ratings within the same
region are combined before combining the regional The Guidesdoes not deny the existence or impor-
impairment rating with that from another region. For tance of these subjective complaints to the individual
example,when there are multiple impairments or their functional impact. The Guidesrecommends
involving abnormal motion,neurologic loss,and that the physician ascertain and document subjective
amputation of an extremity part,these impairments concerns. Because the presence and severity of sub-
firstshould be combined for a regional extremity jective concerns varies among individuals with the
impairment. The regional extremity impairment then same condition,the Guideshas not yet identified an
is combined with an impairment from another accepted method within the scientific literature to
region,such as from the respiratory system. Spinal ascertain how these concerns consistently affect
impairments in multiple regions are combined. organ or body system functioning. The physician is
Exceptions,as detailed in the musculoskeletal chap- encouraged to discuss these concerns and symptoms
ter,include impairments of the joints of the thumb, in the impairment evaluation.
which are added,as are the ankle and subtalar joints
in the lower extremity:both situations include com- Research is limited on the reproducibilityand
plex motions. validityof the Guides.18-20Anecdotal reports indicate
that adoption of the Guidesresults in a more stan-
dardized impairment assessment process. As relevant
research becomes available,subsequent editions of
the Guideswill incorporate these evidence-based
studies to improve the Guides’reliability and validity.