304 Pain Management
Thus, it can only be assessed indirectly based on a patient•s
overt communication, both verbal and behavioral.
Pain is a complex, subjective phenomenon comprised of a
range of factors and is uniquely experienced by each person.
Wide variability in pain severity, quality, and impact may be
noted in reports of patients attempting to describe what
appear to be objectively identical phenomena. In addition,
patients have a different frame of reference from that of the
caregiver. These unique views may complicate communica-
tion between patient and caregiver and prevent direct com-
parisons among patients from different backgrounds and with
different experiences. Patient•s descriptions of pain are also
colored by cultural and sociological in”uences. It is the
unique experiences of each patient that make assessment of
pain so dif“cult.
Physical and Laboratory Factors
Dif“culties in assessing the physical contributions to chronic
pain are well recognized. There are no universal criteria for
scoring the presence or importance of a particular sign (e.g.,
positive radiographs, limitation of spinal mobility), quanti-
fying the degree of disability, or establishing the association
of these “ndings with treatment outcome. Interpretation of
biomedical “ndings relies on clinical judgments and medical
consensus based on a physician•s experience and in some
instances quasi-standardized criteria. There remains a good
deal of subjectivity both in the manner in which physical
examinations are performed and diagnostic “ndings are
interpreted.
The inherent subjectivity of physical examination is most
evident when it is noted that agreement between physicians is
better for items of patient history than for some items of the
physical examination. The reproducibility of physical evalu-
ation “ndings, even among experienced physicians, is low.
For example, multiple observer agreement in physical exam-
ination of spinal motion and muscle strength, even when
using standard mechanical assessment devices such as dy-
namometers, can be surprisingly poor (Hunt et al., in press).
The discriminative power of common objective signs of
pathology determined during physical examination has also
been questioned. Physical and laboratory abnormalities cor-
relate poorly with reports of pain severity. There is no direct
linear relationship between the amount of detectable physical
pathology and the intensity of the pain reported.
Some of the variability in results may be associated with
the patient•s behavior during the examination. Measures
of ”exibility or strength often re”ect nonphysical subjec-
tive state as much as actual physical capabilities. Thus, al-
though physical examination is more objective that patient
reports, patient motivation, efforts, and psychological state
in”uence it.
For signi“cant numbers of patients, no physical pathology
can be identi“ed using plain radiographs, CAT (Computed
Axial Tomography) scans, or electromyography to validate the
report of pain severity. Even with sophisticated advances in
imaging technology, there continues to be a less-than-perfect
correlation between identi“able pathology and reported pain
as we noted earlier. In sum, routine clinical assessment of
chronic pain patients is frequently subjective and often unre-
liable. It is often not possible to make any precise pathological
diagnosis or even to identify an adequate anatomical origin
for the pain. Despite these limitations, the patient•s history
and physical examination remain the basis of medical diagno-
sis and may be the best defense against over-interpreting re-
sults from sophisticated imaging procedures.
Physicians must be cautious not to over-interpret either
the presence or absence of objective “ndings. An extensive
literature is available focusing on physical assessment, radi-
ographic, and laboratory assessment procedures to determine
the physical basis of pain and the extent of impairments in
adults. For a recent discussion of some of the complexities
involved see Turk and Melzack (1992, 2001).Psychosocial ContributionsAny physical abnormalities that are identi“ed may be modi-
“ed by coexisting psychosocial in”uences. The complexity
of pain is especially evident when it persists over time as a
range of psychological, social, and economic factors interact
with physical pathology to modulate patients• reports of pain
and the impact of pain on their lives. In the case of chronic
pain, health care providers need to search not only for the
physical source of the pain through examination and diag-
nostic tests but also the patient•s mood, fears, expectancies,
coping efforts, resources, responses of signi“cant others, and
the impact of pain on the patients• lives. In short, the health
care provider must evaluate the whole patient not just the
cause of the pain. Regardless of whether an organic basis for
the pain can be documented or whether psychosocial prob-
lems preceded or resulted from the pain, the evaluation
process can be helpful in identifying how biomedical, psy-
chosocial, and behavioral factors interact to in”uence the
nature, severity, and persistence of pain and disability.
We (Turk & Okifuji, 1999) have suggested that three cen-
tral questions should guide assessment of people who report
pain:1.What is the extent of the patient•s disease or injury (phys-
ical impairment)?