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LETTER TO THE EDITOR
A note on the theoretical framework of World Health Organization
Disability Assessment Schedule II
STEFANO FEDERICI
1,2
& FABIO MELONI
2,3
1
Department of Human and Education Science, University of Perugia, Perugia, Italy,
2
CIRID, Interdisciplinary Centre for
Integrated Research on Disability, University of Rome ‘La Sapienza’, Rome, Italy, and
3
Department of Psychology, University
of Rome ‘La Sapienza’, Rome, Italy
Accepted August 2009
An overview on the A. Schlote et al.’s study
With our 2007 study on knowledge and spread of
biopsychosocial model of disability (launched by the
ICF – International Classification of Functioning,
Disability and Health [1]) among teachers, educators,
and disabled students’ parents [2,3], we soon realized
that an adequate understanding of the model itself and
its applications was a long way off. Nevertheless, we
were certain that the concepts of functioning, dis-
ability, and health, according to the theoretical
perspective of the biopsychosocial model, were widely
understood, at least within international scientific
community. We, therefore, are quite surprised with A.
Schlote, M. Richter, M.T. Wunderlich, U. Poppen-
dick, C. Moller, K. Schwelm, and C.W. Wallesch
research entitled ‘WHODAS II with people after
stroke and their relatives’ [4] recently published in this
journal because it seems as if these concepts are not
shared by these researchers.
A. Schlote et al. intend to measure the internal
consistency and the validity of the World Health
Organization Disability Assessment Schedule II
(WHODAS II), besides the inter-rater-correlation
among the scores gathered by the administration of
the tool to patients with stroke and their closest
significant others. In a articulated and not always
clear experimental procedure, during which data
have been collected to analyze the psychometric
validation, the 36 items version of WHODAS II,
the modified Rankin Scale (which assesses the
functioning limitations of people after stroke), and
the National Institute of Health-Stroke Scale
(a diagnostic scale that assesses typical stroke-related
neurological deficits) have been administered. The
results indicate, according to the international
scientific literature [5], that the WHODAS II is a
valid, generally reliable and useful instrument for the
assessment of patients with stroke over the 1st year
after stroke.
Herein, we will demonstrate A. Schlote et al.’s
serious errors in defining the theoretical model of the
WHODAS II and in doing so critically comment on
some aspects of their experimental design.
Is the WHODAS II a measurement of the
disability as a consequence of a disease or of the
individual functioning irrespective of medical
diagnosis?
From the beginning of the article it is clear that the
A. Schlote et al. do not have a clear understanding of
what the WHODAS II is because they state the
WHODAS II is ‘a standardized instrument for the
assessment of limitations and restrictions resulting
from illness.’ [4, p 855]. A. Schlote et al.’s statement
contradicts the definition upheld by the ICF’s health
and individual functioning model, and of course the
definition as given in the WHODAS II’s Training
Manual, ‘The WHODAS II has been developed to
assess the activity limitations and participation
restrictions experienced by an individual irrespective
of medical diagnosis’ [6, p 10]. The novelty of
the WHODAS II approach resides in supporting
that individual functioning self-perception and/or
disability is not a direct and immediate result of
Correspondence: Stefano Federici, Department of Human and Educational Sciences, University of Perugia, Piazza G. Ermini, 1-06123 Perugia, Italy.
E-mail: stefano.federici@unipg.it
Disability and Rehabilitation, 2010; 32(8): 687–691
ISSN 0963-8288 print/ISSN 1464-5165 online ª2010 Informa UK Ltd.
DOI: 10.3109/09638280903290012
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morbidity of a disease, such as it has been diagnosed
by objective and standardized criteria. Therefore, for
the same morbidity, the same health condition may
be perceived by different individuals and in different
contexts as differently disabling.
In A. Sen’s well-known research [7] on the
differences of the self-perception of own pathological
condition (morbidity), Americans were found to
have a morbidity score 10 times higher than the one
perceived by people of Bihar, one of the poorest
Indian state. According to this research, we should
arrive at the counterintuitive inference that the health
conditions of people of Bihar are better than the ones
of Americans. But is this actually counterintuitive? If
we consider that individual’s health is something
more than the simple medical conditions, then the
answer is ‘No’. If we understand the important
contribution that the biopsychosocial model of
disability may offer to understand that health, and
health-related components of well-being, we see that
one’s ‘health’ goes beyond medical indications.
According to the ICF’s theoretical model, disability
is no more intended as an obvious consequence of a
pathological health condition but as a specific,
momentary or permanent, manner of an individual’s
‘functioning’ in a certain context. For these reasons,
we can assert that ICF ‘does not classify people, but
describes the situation of each person within an array
of health or health-related domains’ [1, p 10].
It is just this possibility, offered by the tool, to
assess the degree of self-perceived disability, inde-
pendently from a medical diagnosis (and then from
the disease), which makes WHODAS II a concep-
tually compatible tool with the ICF. The WHODAS
II deals with one of the aspects of that new language
introduced by the ICF that, according to several
scholars [8] represents a basic reference point for a
new health concept universally accepted, that how-
ever appears to be neglected by the A. Schlote et al.
Is the ICF a classification of a person’s damage
or functioning?
In several passages, we are left doubting whether A.
Schlote et al. have fully understood the meaning of
the ICF’s new classification. The use of words such
as ‘activity’ and ‘participation’ often just superficially
seems to refer to the meaning ascribed by the ICF,
and seem on the contrary to be consistent with the
meanings supported by ICIDH – International
Classification of Impairments, Disabilities, and
Handicap’s [9] old classification system. This appar-
ent use of an old classification system is evinced
when A. Schlote et al. justify the validity of
WHODAS II, by quoting a 1983 United Nations
disability definition which is consistent with the
ICIDH concepts and not the ICF ones.
An example of this confusion can be found in the
following statement, which highlights a medical
perspective of disability, rather than a biopsychoso-
cial one, yet still referring to the ICF theoretical
model:
‘ICF aims to be a globally applicable and standardised
framework for the description and classification of health
and health related conditions. The ICF takes into
account damage to body structures, impairments of
body functions, of activities and participations as well as
context factors of influence and thus relates to a
biopsychosocial model of health, or disease, respectively’
[4, p 855].
This statement is false as it does not accurately
represent the ICF theoretical model. For the ICF,
classification does not take into account damages or
impairment but functioning. There is no code of the
taxonomy that classifies impairment, or disability or
handicap. Therefore, this is the structure of the
ICIDH, where categories describe different structur-
al and functional impairments, different disabilities
and handicaps resulting from impairment. On the
contrary, in no ICF category is impairment or
disability classified. As a consequence, in the ICIDH
one may find a damage to a body structure, such as
‘Absence of eye’ (code number: 50), but in the ICF
we find the only description of structure, such as
‘Structure of eye socket’ and ‘Structure of eyeball’
(code number: s210 and s220) and of corresponding
function, such as ‘Seeing functions’ (code number:
b210).
Therefore, only in the ICIDH is there a taxonomy
of ‘Seeing Disabilities’ (code number: 25–27), which
is wholly absent in the ICF. As the new classification
states:
‘ICF has moved away from being a ‘‘consequences of
disease’’ classification (1980 version) to become a
‘‘components of health’’ classification. ‘‘Components
of health’’ identifies the constituents of health, whereas
‘‘consequences’’ focuses on the impacts of diseases or
other health conditions that may follow as a result.
Thus, ICF takes a neutral stand with regard to etiology
so that researchers can draw causal inferences using
appropriate scientific methods. Similarly, this approach
is also different from a ‘‘determinants of health’’ or ‘‘risk
factors’’ approach. To facilitate the study of determi-
nants or risk factors, ICF includes a list of environ-
mental factors that describe the context in which
individuals live’ [1, p 5].
The pertinence of the literature cited and
discussed
Another embarrassing misunderstanding of A.
Schlote et al. is their ascription to the ICF theoretical
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framework that is demonstrated by their citation of
an excellent yet obviously dated research (i.e. the
famous article of Engel, published on Science in
1977, entitled ‘The need for a new medical model: a
challenge for biomedicine’ [10]) to defend their
position. We wonder why they do not consider all the
theoreticians of the biopsychosocial model that since
the 1977 have not only accepted Engel’s challenge
but have also substantially developed Engel’s insight
[11]. We cannot resist formulating the following
analogy: Quoting Engel about the biopsychosocial
model is like referring to Copernicus to explain
Kant’s Copernican Revolution.
Another critique regarding the literature quoted
and discussed is the lack of relevant and compre-
hensive literature. For instance, when the A. Schlote
et al. inaccurately assert that ‘[WHODAS II]
psychometric properties have not yet been evaluated
for its use in this [stroke] condition’ [4, p 856]. This
is an inaccurate because while the amount of studies
which survey the psychometric features of the
WHODAS II is not high [12–19], there are at least
three studies that evaluate such properties with
patients after stroke [20–22]. Analogously, A.
Schlote et al.’s affirmation ‘objectivity of interpreta-
tion has not yet been established, as norms are not
yet available’ is just flat wrong. Actually, not only
does the general population norms exist, but even
more that one on specific category of patients are
available on demand at the Home Page for the World
Health Organization Disability Assessment Schedule
II [23]. Finally, A. Schlote et al. seem to believe that
the application of the WHODAS II is scarce and
evaluated just for a small number of diseases, again
this is just flat wrong as more than 50 published
studies exist [5].
Is disability a prerequisite for handicap or a
condition of individual functioning?
As a consequence of the misinterpretation of the
theoretical construct of the ICF and the WHODAS
II, A. Schlote et al. implicitly and explicitly adopt a
disability definition that does not coincide in any way
with the one claimed by the biopsychosocial model.
Therefore, much of the methodology, the tools
administered, and the interpretation of the results
appear to us to be justified by a vision of disability as
a ‘prerequisite for handicap’ and a consequence of a
disease [4, p 862].
Around the conclusion of the article A. Schlote
et al. reveal the motivation for their use of WHODAS
II. Their motivation is revealing because it helps to
demonstrate the complete theoretical and conceptual
incongruence of their motivations in the using of the
WHODAS II. It is worthwhile to quote a paragraph
from the conclusion of Schlote et al.’s article as it
clearly reveals the basic problems of A. Schlote
et al.’s conceptual framework:
‘Al1 in all, the interrelations found were even higher
than those reported by other authors for the SF-36 [. . .].
It could be criticised that the Rankin Scale is a rather
coarse instrument that does not assess limitations and
restrictions but rather participation. On the other hand,
we did not feel justified to validate WHODAS II against
instruments such as the SF-36, which follows a very
different concept, i.e. health related quality of life.
Following the definition of the United Nations ‘‘Handi-
cap is a disadvantage for a given individual, resulting
from an impairment or disability. . .’’ [. . .], we consider
disability/activity limitation a prerequisite for handicap/
participation restriction. Consequent1y, values on the
Rankin Scale should correspond to those of an instru-
ment assessing disability’ [4, p 862].
As indicated previously the Schlote et al.’s view of
disability seems to match the ICIDH one, whose
definition of disability is: ‘Any restriction or lack
(resulting from an impairment) of ability to perform
an activity in the manner or within the range
considered normal for a human being’ [9, p 143];
and of handicap which is: ‘A disadvantage for a given
individual, resulting from an impairment or disabil-
ity, that limits or prevents the fulfilment of a role that
is normal [. . .] for that individual’ [9, p 183]. The
ICF, on the other hand, affirms in a note [1, p 191]
that the concept ‘activity limitation’ and ‘participa-
tion restriction’, respectively, replace ‘disability’ and
‘handicap’ used in the 1980 version of the ICIDH.
Nevertheless, herein the problem is not only a mere
concept substitution, but it requires the concepts to
be understood in the new ICF framework, as follows:
‘ICF differs substantially from the 1980 version of
ICIDH in the depiction of the interrelations between
functioning and disability. It should be noted that
any diagram is likely to be incomplete and prone to
misrepresentation because of the complexity of
interactions in a multidimensional model. The
model is drawn to illustrate multiple interactions.
Other depictions indicating other important foci in
the process are certainly possible’ [1, p 25].
Moreover, it is well-known that during the revision
process from ICIDH to ICF the term handicap was
abandoned, accepting the requests from the English
speaking countries which considered the term
‘handicap’ stigmatizing and discriminating [1, pp
187–188]. On the contrary, in the Schlote et al.’s
words, it seems that the shift from the old classifica-
tion to the new one has involved a simple termino-
logical variation in a theoretical view fundamentally
unchanged: new words for old schemes.
The relationship between ‘activity limitation’ and
‘participation restriction’ does not have, within the
ICF’s biopsychosocial model, a consistent nature, as
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the A. Schlote et al. seem to suggest. That the
‘participation restriction’, that is ‘handicap’ (accord-
ing to the old terminology used before the ICF), is a
consistent, sequential, and unidirectional conse-
quence of an ‘activity limitation’ (resulting from an
impairment) is the expression of the model which
characterized the ICIDH and the United Nations
declaration (quoted by the Authors) during the
1970s, but it is not related with the ICF.
Indeed, in the ICF, the disability, intended as an
umbrella term, is the multidetermined outcome of
three components: (i) body structures and func-
tions; (ii) environmental factors; and (iii) personal
factors, which reciprocally interact in a circle cause
relationship:
‘Functioning is an umbrella term encompassing all body
functions, activities and participation; similarly, disabil-
ity serves a san umbrella term for impairments, activity
limitations or participation restrictions. [. . .] A person’s
functioning and disability is conceived as a dynamic
interaction between health conditions (diseases, dis-
orders, injuries, traumas, etc.) and contextual factors,
[. . . where such as] this interaction can be viewed as a
process or a result depending on the user’ [1, p 3.10].
Therefore, the functioning/disability/health model
which rises from the ICF, and that is shared by the
WHODAS II, is much more complex that the
Authors intend in their article.
In the same way, it is not clear why A. Schlote
et al. may refer to the ‘World Programme of
Action Concerning Disabled Persons’ by the United
Nations of 1983 [24], but seem to neglect the more
recent ‘Convention on the Rights of Persons with
Disabilities’ according to that the ‘disability is an
evolving concept and that disability results from the
interaction between persons with impairments and
attitudinal and environmental barriers that hinders
their full and effective participation in society on an
equal basis with others’ [25, p 5].
Finally, the statement that the WHODAS II
should not be validated in relation to the SF-36 is
clearly disproved by the remarkable amount of
studies that, in a biopsychosocial view, draw the
concept of functioning/disability near the one of
quality of life [5].
Conclusions
Our aim is not to criticize or defend one definition of
disability among the others, but to point out the
incoherence in Schlote et al.’s definition of the
disability. If one adopts the WHODAS II as a
measurement tool, the conceptual framework –
according to the background in which the tool has
been conceived – must be the ICF one. Otherwise, if
one refers to the ICIDH conceptual viewpoint, it is
necessary to set up a measurement tool adequate to
a definition of disability which arises from that
framework. The logical consequence is that if
scholars do not want to reduce statistical results to
mere quantitative scores, but consider them
grounded on scientific theoretical hypotheses and
expected results, then scholars must deeply exam-
ine, understand and accurately refer to relevant
literature. According to our opinion, the Schlote
et al.’s misunderstanding of the WHODAS II and
the ICF theoretical framework compromises their
experimental design, so that (i) their choice of using
the Rankin Scale, rather than the SF-36 for the
convergent validation arises from the confusion
between the linear model of disability (ICIDH)
and the circular and multi-determined model (ICF)
which (ii) leads Schlote et al. to confirm their
experimental hypotheses, but for all the wrong
reasons.
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