FROM DISABLEMENT TO ENABLEMENT:

CONCEPTUAL MODELS OF DISABILITY IN THE TWENTIETH CENTURY

AUTHORS:

1. CARMELO MASALA

AFFILIATION: DEPARTMENT OF PSYCHOLOGY – UNIVERSITY OF CAGLIARI – ITALY

2. DONATELLA RITA PETRETTO

AFFILIATION: DEPARTMENT OF PSYCHOLOGY – UNIVERSITY OF CAGLIARI – ITALY

OFFPRINT REQUESTS:

PROF. CARMELO MASALA

DIPARTIMENTO DI PSICOLOGIA

UNIVERSITA’ DEGLI STUDI DI CAGLIARI

LOC. SA DUCHESSA

01927 CAGLIARI

ITALIA - EUROPA

E-MAIL ADDRESS masala@unica.it, drpetretto@unica.it

FAX NUMBER: 0039070274778 – 0039070291204

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ABSTRACT

PURPOSE: The aim of this work is to provide a general view of the conceptual elaborations

on disablement in the twentieth century and to discuss the role of these different contributions

in developing the current concepts of disablement.

METHOD: A review of the literature on conceptual models of disablement in the past century

has been performed.

RESULTS: The Twentieth century has witnessed important theoretical considerations on

health, diseases and their consequences. These considerations have generated various

conceptual models, some of which share the same focus and point of arrival, the so-called

‘Disablement Process’. Among the models that were developed two stand out, which were

drafted and disseminated under the aegis of the World Health Organization, namely the

International Classification of Impairments, Disabilities and Handicaps (I.C.I.D.H.) ([1]) and

the International Classification of Functioning, Disability and Health (ICF) ([2]), but these are

just one part of the conceptual elaboration in the field. Further conceptualization was

produced in health and social settings by specialists, self-advocacy associations and activist

groups.

CONCLUSIONS: The current ICF model of the World Health Organization has been

translated and recognized in 191 countries; it also incorporates the contribution of self-

advocacy associations and it is now recognized by most of them. This model has enjoyed

higher visibility than other conceptual models, though its level of development was not higher

or more original. To our opinion the ICF is not very clear on the essential choice of the model,

i.e. to see disablement as a dynamic process that happens when personal limits collide with

socio-environmental needs, rather than as a personal feature. This choice is instead clearer in

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other models, like Nagi’s 1991 ([3]), the Institute of Medicine (IOM) model by Brandt and

Pope ([4]), where the identification of three dimensions (the individual, the environment and

the individual-environment interaction) clarifies the role played by all three dimensions

within the process of disablement and introduces major hints for further considerations on

how to create virtuous processes of enablement ([4]).

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INTRODUCTION

The Twentieth century has witnessed important theoretical considerations on health,

diseases and their consequences. These considerations have generated various conceptual

models, some of which share the same focus and point of arrival, the so-called ‘Disablement

Process’. But while the first formulations saw this process as dependent upon the

characteristics of the individual (his/her pathology and impairments), subsequent concepts

attributed a progressively growing role to the environment (in its physical and social aspects).

Among the models that were developed two stand out, which were drafted and

disseminated under the aegis of the World Health Organization, namely I.C.I.D.H. and ICF

([1],[2]), but these are just one part of the conceptual elaboration in the field.

Further conceptualization was produced in health and social settings by specialists,

self-advocacy associations and activist groups. Specialists focussed on defining the criteria of

eligibility for various forms of assistance and aids (welfare services and economic funds). The

latter groups strived to achieve the acknowledgement of inalienable rights and of measures

safeguarding against marginalization and stigmatization. Both contributions have partially

met in the current ICF model of the World Health Organization that has been disseminated,

translated and recognized in 191 countries; it also incorporates the contribution of self-

advocacy associations, most of which recognize it now.

The aim of this work is to provide a general view of the conceptual elaborations on

disablement and to discuss the role of these different contributions in developing the current

concepts of disablement.

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THE CONTRIBUTION OF SAAD NAGI AND THE FIRST MODEL OF THE

WASHINGTON INSTITUTE OF MEDICINE

Among the contributions from health and rehabilitation settings, at the end of the

1950’s there came the work by Saad Nagi, a sociologist of Egyptian origin. This author

started from sociological considerations and later, believing that medicine was exerting too

strong a control over the issues linked to disablement, decided to shed light on the role played

by some factors - not necessarily linked to pathology and impairments - in shaping

disablement. In fact he introduced a dynamic view of disablement and of the functional

consequences of the pathology, these consequences being hard to foresee at a first glance

when studying the active pathology in the individual. Nagi developed a model that, beyond

being the base to explain rehabilitation issues theoretically and empirically, had the aim of

serving as a reference point to plan interventions to distribute welfare and economic aids

(Nagi, 2006, Personal communication). Although Nagi had already studied these topics

earlier, he is known for his contributions while working at the Institute of Medicine (IOM) of

Washington. He is often mentioned as a model for the IOM1, for which he worked to define

the criteria of eligibility for two forms of economic aid called Social Security Disability

Insurance (SSDI) and Supplemental Security Income (SSI), as introduced by the Social

Security Act of the United States of America.

1 Actually there are two IOM models that refer to Nagi’s work ([3]): one dating from 1991 ([4]) and published in a book entitled “Disability in America”, by Pope and Tarlov; the other published in 1997 in the book “Enabling America” by Brandt and Pope ([5]). The first book saw the personal participation of Nagi, who had been invited to develop the model but could not do it directly, so he commented on the model later in the book. The second work contains a reworking of his research. As we will see later on in the paper, a further analysis was carried out in 1994 by Verbrugge and Jette ([6]).

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In his attempt to overcome a restrictive view, whereby the presence of a pathology or

of an impairment was considered enough to hamper functional capabilities (in general, and

working skills in particular), Nagi developed a model that described the process whereby an

individual with a specific active pathology can have some functional limitations and some

disabilities. He defined disability as an ‘expression of a physical or a mental limitation in a

social context’ ([3], page 101): a gap between the individual’s capabilities and the demands

created by the physical and social environment. Nagi developed a model that describes

disablement through four concepts: active pathology, impairment, functional limitation and

disability, which had been used as synonyms till then.

He defined active pathology as ‘a state of the body’s defences and coping

mechanisms’ caused by infections, trauma, metabolic imbalance, degenerative disease

processes, or other pathologies ([3], page 101). A consequence of pathology can be

impairment, which Nagi described as ‘a loss or abnormality at the tissue, organ, and body

system level’, but not all impairments are associated with active pathology. In its turn,

impairment can produce effects in terms of functional limitations, which he defines as

limitations in ‘the individual’s ability to perform the tasks and obligations of his usual roles

and normal daily activities’ (e.g. seeing, walking, listening), or in terms of disablement, i.e.

limitations in performing socially defined roles (e.g. employment or self-care) ([3], page 101-

102). To describe functional limitations he mentions, for example, locomotion limitations (in

gait, or in mobility) secondary to a cerebrovascular accident, or limitations in non-physical

tasks, such as communication or reasoning. These limitations may as well be independent

from impairments.

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According to Nagi, disablement would be the expression of functional limitations in

the social context, i.e. the product of the interaction between the individual and the

environment that poses demands to individuals. Since the first version of his model, Nagi

explicitly acknowledged the role played by the social environment in the disablement process.

In this sense this model represents a highly advanced model of disablement conceptualization

as early as the 1960’s.

THE BRITISH EPIDEMIOLOGICAL STUDY BY HARRIS: THE LINKS BETWEEN

REDUCED AUTONOMY AND POVERTY

In the 1960’s Great Britain too lived a major reflection on the relationship between

pathologies and functional consequences. Considerations were at a governmental level

mainly, out of the growing awareness that a certain number of people were living in extreme

poverty as a consequence of their lower degree of autonomy and ability to work. This

awareness lead to an epidemiological study aimed at detecting the correlation between

poverty and reduced autonomy, and also at developing tools for interventions and prevention.

In the years 1968-69 Amelia Harris and the Social Survey Division, on behalf of the Office of

Population Censuses and Surveys (OPCS), made the first British study to assess the frequency

of ‘impaired’ and ‘handicapped’ people entitled ‘Handicapped and Impaired in Great Britain’

([7]). The aim of the study was to collect epidemiological data. Harris called ‘impairment’ the

loss of a limb, partially or wholly, or the presence of a dysfunctional limb, organ or body part;

with ‘handicap’ she meant the loss or the reduction of one or more functional abilities

(including self-care, using the toilet, feeding, getting dressed, performing the postural changes

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to get up and lay down the bed, washing, taking a bath, buttoning, putting one’s stocks on,

women’s combing their hair and men’s shaving). She classified as "impaired" those who had

one impairment at least, and "handicapped" those who experienced difficulties in performing

one or more of the above-described activities. Based on these definitions, about 8-9 people

with an impairment were identified every 1000 inhabitants (and up to 378 people every 1000

when older than 75 years), for a total amount of three million people older than sixteen years

of age. According to the study, about 4% of the whole population aged 16-64 years had some

impairment and about 28% of the people older than 65 had some form of impairment, with

the male/female ratio unfavourable to the latter (1:2). Of these, about half a million people

would be classified as handicapped.

Harris’ work was not exempt from criticism, more on methodology than terminology:

critics said that her having taken into consideration only those who lived in their homes could

have underestimated the issue, particularly given the high incidence of people living in

institutions at the time. Also the terminology chosen by the author was criticized: the term

‘handicapped’ associated to the presence of a functional limitation was judged wrong and

discriminatory. Nevertheless, Harris’ study too is an example of the concepts and of the

considerations on disablement made in Great Britain in those years. It refers not so much to

the dynamics of disablement, but rather to the quantifying efforts aimed at detecting the

prevalence of this occurrence in the British population.

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WOOD’S GROUP AND THE I.C.I.D.H. MODEL OF THE WORLD HEALTH

ORGANIZATION

Harris’ research was the subject of analysis and research by a group of operators from

the Arthritis and Rheumatism Council Epidemiology Research Unit of the University of

Manchester, coordinated by Philip Wood and Elizabeth Badley. They tried to shed light on

the terminology used by the author and highlighted both the confusions in her work, and her

tendency to use ‘impairment’ and ‘handicap’ as if they were interchangeable ([8]). The

considerations of these authors on Harris’ study, as well as their previous studies, were made

in parallel with a job entrusted to them by the World Health Organization. Wood had been a

consultant to the WHO during the revision stage of I.C.D.-9. While in Geneva, he had the

opportunity to see the new model that the WHO wanted to develop to the aim of describing

the consequences of pathologies. He saw the first version of this model that classified

impairments, and put forward his considerations that derived from his studies on rheumatoid

arthritis, and also from his analysis of Harris’s work. This earned him the task to revise the

first version of this new model; his work became known internationally on occasion of the

29th Assembly of the World Health Organization in May 1976, when it was presented to the

public and the Assembly resolved to publish it for research purposes (Resolution WHA

29.35). It was named International Classification of Impairments, Disabilities and Handicaps

(I.C.I.D.H.) and put into force by the World Health Organization in 1980 ([1]). This model

was aimed at analysing, describing and classifying the consequences of diseases, such

consequences being distinguished between impairments, disabilities and handicaps.

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Wood and his group defined impairment as ‘any loss or abnormality of psychological,

physiological, or anatomical structure or function’ ([9], page 47). Disability was defined as

‘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], page 143). And,

finally, they defined handicap as ‘a disadvantage for a given individual, resulting from an

impairment or a disability, that limits or prevents the fulfilment of a role that is normal

(depending on age, sex, and social and cultural factors) for that individual’ ([9], page 183).

The I.C.I.D.H. model sees impairment, disability and handicap as three different levels

of pathology consequences, which are related to different levels of experience and of

individual awareness. Though the text of the model proposed a mechanism of multiple links

among the levels instead of a linear connection, the graphic representation that was produced

with the I.C.I.D.H. model hinted at the presence of linear and direct links among the three

levels of pathologic consequences. The model was widely criticised, above all its supposed

logic of a linear link among the levels, the overlapping of levels and the ambiguous definition

of handicap. In fact though this was defined as the socialization of the experience of an illness

and as a ‘disadvantage’, the fact of having it derive from an impairment or a disability and of

linking it to non-performance of survival tasks introduced unforeseeable connections (though

necessary and unavoidable) between the disease and the disadvantage in the individual. These

connections were born of interpretations of the model that had been foreseen by its authors

but only partly2; they earned much criticism on the model and, above all, the firm opposition

2 The ambiguity that associates to the definition of handicap in the I.C.I.D.H. is even more striking in the central part of the

manual that deals with the experience of the disease, where handicap is described as follows: “Either the awareness itself, or the altered behaviour or performance to which this gives rise, may place the individual at a disadvantage relative to others, thus socializing the experience. This plane reflects the response of society to the individual’s experience, be this expressed in attitudes, such as the engendering of stigma, or in behaviour, which may include specific instruments such as legislation. These experiences represent handicap, the disadvantages from impairment and disability” ([8], page 26). In this case explicit

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of self-advocacy movements and activist groups, who saw in this model the basis for further

discrimination against people with impairments.

The I.C.I.D.H. model was the first internationally shared conceptual formulation (it

was translated into 13 languages) and the first international system to classify the

consequences of diseases. Nevertheless it was exactly its conceptual organization that

attracted most criticism and caused the subsequent difficulties in detecting the consequences

of diseases. It soon underwent a revision, this process lasting throughout the 1980's and

yielding the first results at the beginning of the 1990's. The first revision saw the participation

of several expert committees, as the one created by the European Council in 1987, and of 14

European countries. Wood himself took part in the activity of expert committees ([10-11]). In

1993 the model was reissued with a preface that acknowledged the shortcomings of the

previous version and listed the points to be dealt with in the revision work to come ([9]).

THE MOVEMENTS FOR THE RIGHTS OF ‘ENVIRONMENT-DISABLED PEOPLE’

In parallel with epidemiologic, taxonomic and welfare contributions there developed a

lively debate in those same years, which stemmed from the dissatisfaction of many people

who, because of their impairments and autonomy limitations, were the recipients of

paternalist interventions and of actions that limited their freedom and their human and social

rights. In fact the countries analyzed so far were recording a strong trend towards

institutionalizing those people who suffered from functional limitations and towards

reference is made to stigma or to behaviours through which the response of society becomes evident. If handicap was de-scribed before as a disadvantage deriving from impairment or disability, in this section of the manual contains a more explicit reference to the environment.

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marginalizing them. In Great Britain, for example, at the beginning of the 1970’s a group of

people institutionalized out of their impairments asked a group of local professionals for their

support, for them to start a study that would assess their quality of life and the measures apt to

improve it. The study that resulted, though acknowledging the highly discriminating and

disempowering situation the clients were experiencing, proved unable to launch intervention

or preventative measures. This is why the same people who had ordered the study created

their own association to the aim of having their rights recognized ([12]). If Nagi, Harris and

Wood had tried to define and describe the relationship between a pathology and its functional

consequences, so as to identify the recipients of economic and welfare support measures, the

group formed by those who were being discriminated in the first place tried to understand

why some people, who have bodily functional or structural deficiencies, are being excluded.

In the 1970’s Britain saw the birth of ‘Disabled People’s International’ (DPI), which was

paralleled by the ‘Society for Disability Studies’ (SDS) in the USA in the 1980’s. DPI formed

UPIAS (‘Union of the Physically Impaired Against Segregation’) that, in 1975, developed its

own disablement model that is now renown internationally as the ‘social model of disability’3

as fully opposed to what they themselves defined the ‘medical model of disability’. According

to this model, some people suffering from functional and structural impairments are deprived

of their authority and forced to play secondary roles in society on the basis of physicians’ and

health professionals' decisions that influence all the aspects of their lives. To fight this

traditional way of behaving against the people with functional and structural limitations, the

3 We deem it important to underline that most scholars who studied this issue match their personal experience with

university or study experiences. The expression “social model of disability” is attributed to the disabled writer Mike Oliver who, in 1983, used it to define the influence of society and of its organization on the manifold deprivations experienced by disabled people ([13]). In this respect the South-African psychologist, now living in England, Vic Filkelstein is mentioned as well. One of the founding members of UPIAS, in 1980 he stated that disablement was to be conceived as the direct result of the development of the Western industrial society.

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members of UPIAS developed a two-tier concept model composed of impairment and

disability. They published this model in an official document entitled ‘Fundamental Principles

of Disability’, where they defined the disablement process ascribing much responsibility to

society, which ‘disabled physically impaired people… Disability is something imposed on top

of our impairments, by the way we are unnecessarily isolated and excluded from full

participation in society’ ([14], page 3).

Therefore they defined impairment as ‘lacking part of or all of a limb, or having a

defective limb, organ or mechanism of the body’ and disability as a ‘disadvantage or

restriction of an activity caused by a contemporary social organisation which takes no or little

account of people who have physical impairments and thus excludes them from participation

in the mainstream of social activities’ ([14], page 14).

The first version of the model dealt with physical impairments only, while only later

was the document applied to all impairments, so as to widen model applicability. This was

made possible by the support of the British Council of Disabled People (BCODP), a national

British body that is governed, too, by people with functional and structural disabilities.

The members of UPIAS were the toughest opposers of the subsequent I.C.I.D.H.

model by the World Health Organization, since this was an example of too an individualistic

approach with a medical base, and contained an explicit reference to the causal and direct link

between impairments, disability and handicap whereby impaired people were made

responsible of their reduced integration into society.

On the contrary, they tried to disseminate a vision where the physical and social

environment shapes the difficulties that people with functional limitations or impairments

encounter, so they tried to eliminate the causal relation between impairment, disability and

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handicap. To define the disablement process they adopted the term ‘disabled’ in the sense of

being deprived (by the environment) of the capability or of the possibility to perform a

specific task. Those years, Europe and the United States saw the birth of organizations aiming

at the recognition of the rights of those people who were running the risk of being disabled or

who were actually disabled by the environment. The opportunity to set up these organizations

came from the will to overcome the forms of oppression, discrimination and segregation

many people were experiencing.

The US movement was called ‘Society for Disability Studies’4. Some differences can

be detected between the British approach and the US one: while the British approach analyzes

the social structure and its impact on people with disabilities, the American approach analyzes

the social roles and the attitudes towards the fact of failing to take on specific roles. However

related these aspects may be, a clear-cut distinction should be made between the two

approaches, since they both entail different studies and interventions. As for the British one,

interventions are aimed at changing the social structure, while the American approach aims at

changing attitudes ([15]).

The two approaches share the attempt to go beyond the medical model, since this

model is highly individualized and puts the blame on the individual. These approaches

highlighted how individualistic the concept of disability had been so far, since it focussed on

what was seen as an inborn deficit and on the ways to improve it, without taking the social

process that disables people into consideration.

4 The “Society for Disability Studies” was founded in 1982 as a section of the “Study of Chronic Illness, Impairment, and Disability (SSCIID)” and renamed “Society for Disability Studies” in 1986. Among its founders: Daryil Evans, Steve Hey, Gary Kiger, John Seidel, Irving Kenneth Zola (in http://www.uic.edu/orgs/sds/).

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Though differing, the two approaches see disabled people as those who experience

disablement following some restrictions created by society. These social restrictions are

discriminatory since they limit the individual’s full and egalitarian participation. This was

explicitly stated by UPIAS in the sentences written above on the disabling role of society, but

it is made clearer in the following words that highlight the oppressive role and draw the

UPIAS approach closer to that of the Society of Disability Studies: ‘Physical disability is

therefore a particular form of social oppression’ ([14], pages 3 and 4). Disability would be the

loss or the limitation of the opportunity to participate, because of physical and social barriers.

Society disables people with impairments: disablement would thus be imposed upon them by

society. It is necessary to remove the barriers created by society, or else this shall constitute

discrimination.

THE 1990’s AND THE REVIEW OF MODELS: FROM DISABLEMENT TO

ENABLEMENT

The 1990’s saw the revision of the models described so far. More specifically, both Nagi’s

model and the one developed by the WHO underwent a revision process. In both cases,

revisions concerned the acknowledgement of the role played by the physical and social

environment in shaping the disablement process. Nagi’s model was revised by the author

himself, by the IOM and by Verbrugge and Jette as well ([16, 5, 6]).

Nagi himself made a review of his model in 1991, the year when his model was

accepted by IOM within the text of ‘Disability in America’ ([5], [16]). In his revision, the

author wished to clarify the role of environmental factors in the process of disablement:

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‘Disability refers to social rather than organismic functioning. It is an inability or limitation in

performing socially defined roles and tasks expected of an individual within a socio-cultural

and physical environment. These roles and tasks are organized in spheres of life activities

such as those of the family or other interpersonal relations; work, employment, and other

economic pursuits; and education, recreation, and self-care.’ ([16], page 315). In the same

work, he also explained the link between the levels he had described: ‘not all impairments or

functional limitations precipitate disability, and similar patterns of disability may result from

different types of impairments and limitations in function. Furthermore, identical types of

impairments and similar functional limitations may result in different patterns of disability’

([16], page 315). And he listed some factors that could operate and mediate the link between

impairments, functional limitations and disabilities: ‘Several other factors contribute to

shaping the dimensions and severity of disability. These include a) the individual’s definition

of the situation and reactions, which at times compound the limitations; b) the definition of

the situation by others, and their reactions and expectations - especially those who are

significant in the lives of the person with the disabling condition (e.g. family members,

friends and associates, employers and co-workers, and organizations and professions that

provide services and benefits); and c) characteristics of the environment and the degree to

which it is free from, or encumbered with, physical and socio-cultural barriers’ ([16], page

315). When listing all of these factors, Nagi introduced the role of an individual’s

characteristics, of his/her reactions but also the role of the environment, which was further

divided into the social environment (reactions and expectations of reference individuals) and

physical environment (that can be made worse by physical barriers). In this sense, Nagi’s

model looks much advanced indeed considering the period it was developed. However though

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it referred to the environment and its role, this was analyzed from the viewpoint of the

demands it poses to an individual, while the disablement process was perceived as a function

of the characteristics of the medical status, of impairments and of their related functional

limitations ([4]).

THE WORK UNDERTAKEN BY THE NATIONAL CENTER FOR MEDICAL

REHABILITATION RESEARCH

Still at the beginning of the 1990’s another conceptual contribution was made on disablement:

namely by the National Center for Medical Rehabilitation Research (NCMRR) of Bethesda,

which was aimed at studying rehabilitation to improve its scientific and epistemological qual-

ity. NCMRR developed a model that describes disability and was based on Nagi’s and

I.C.I.D.H. models, in an attempt to overcome the limits of both: more precisely, the fact of as-

suming a linear causal relationship among the various consequences of pathologies, and fail-

ing to analyze the role of environmental factors in the dynamics of the relationships among

the various levels ([17]. The new model focussed on individuals, and on the way they adapt to

the functional limitations in their own families, in the working environment and in the com-

munity.

This model hypothesised five domains connected one to the other by overlapping points, mul-

tiple links and bi-directional links: pathophysiology, impairment, functional limitations, dis-

ability. A fifth level, i.e. social factors, was introduced as well. The authors of the model de-

scribed disability as ‘A limitation in performing tasks, activities, and roles to levels expected

within physical and social contexts’ ([17], page 24). Function meant ‘the execution of an ac-

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tion’. ([17], page 25). Impairment was defined as ‘a loss or abnormality at the organ or organ

system level of the body. Impairment may include cognitive, emotional, or physiological

function, or anatomical structure, and include all losses or abnormalities, not just those attrib-

utable to the initial pathophysiology’ ([17], page 24). Pathophysiology was meant as ‘the in-

terruption of, or interference with, normal physiological and developmental processes or

structures’ ([17], page 25). Finally they acknowledged the role of societal limitations, which

they described as ‘Restrictions attributable to social policy or barriers (structural or attitudin-

al) which limit fulfilment of roles or deny access to services and opportunities associated with

full participation in society’ ([17], page 25). The predominant role of societal limitations was

introduced in an original way as against the previous models, so as to analyze a basic link

between an individual's adaptation to disability and the social barriers that disabled people run

into and that may restrict their opportunities and their achieving an adequate quality of life.

Some personal factors were described too, that may influence the relationship among the do-

mains and, more specifically, an individual’s response to a specific situation:

- Organic factors that concern the body and its constitutional characteristics, such as

strength, endurance, genetic factors, familial predisposition to certain disorders. Each

of these elements can influence the onset of a disability and the functioning of an indi-

vidual in daily life.

- Psycho-social factors, which mainly concern coping style, motivation, judgement, be-

longing to an ethnic group or to a culture, gender differences, beliefs and more;

- Environmental factors, i.e. the environment where the individual grows up and lives,

influences the way he/she performs daily activities and his/her answers to disablement.

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These factors include social and family support, income, the availability of health ser-

vices, the availability of transport means, and of forms of physical assistance.

According to the authors of the NCMRR model, the interaction among all of these factors

would produce the individual’s response to impairment; each factor may influence the ability

of an individual to adapt to life and to the community, and to reach a good quality of life.

This model was developed the same years that saw the revision of Nagi’s model

([16]), and about one year before the work by Verbrugge and Jette ([7]). The three models

have some points in common concerning both the definition of the proposed disabilities, and

the acknowledgement of the role played by the environment. What is striking is that all three

models, though acknowledging the role of the physical and social environment, refer to a

main path that links pathology (or pathophysiology) to its functional consequences.

As already written above, about one year later a second revision of Nagi’s model was

developed by Verbrugge and Jette who, integrating this model with I.C.I.D.H., developed a

new disablement model so as to describe: ‘1) how chronic and acute conditions affect

functioning in specific body systems, fundamental physical and mental actions, and activities

of daily life, and 2) the personal and environmental factors that speed or slow disablement;

namely, predisposing risk factors that propel dysfunction, interventions inserted to avoid,

retard or reverse it, and exacerbators that hasten it’ ([7], page 1). They too, like Nagi, saw

disability as a gap between the capabilities of an individual and the demands made by the

social and physical environment; they tried to describe some of the variables that can mediate

the disablement process, by acting as a moderator and a mediator in the relations between

pathology, impairment, functional limitation and disability.

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They described the factors that precede the onset of disablement, e.g. the individual’s

lifestyle or socio-demographic and biological factors, which may constitute risk factors or

predisposing factors. Other factors are related to the process already underway and may be

divided between intra- and extra-individual ones; moreover, since they can limit or exacerbate

the disablement process, they are classified as interventions or as exacerbating factors. The

intra-individual factors operate within a person, as for example the lifestyle, or coping

strategies, while extra-individual factors concern the physical and social setting where the

process takes place. These include the quality of the therapeutic regimen, the social network

the individual belongs to and the physical environment where he/she lives. These factors may

act individually, or else they can all act simultaneously, causing immediate, delayed or

cumulative effects.

The whole set of risk or predisposing factors and of intra- and extra-individual factors

can operate on all four levels of the main path, as discussed above. The interaction among all

of these levels starts the disablement process. Individuals sharing the same active pathology,

or impairment, or functional limitation, might experience different levels of disablement

according to the influence of the predisposing risk factors, or of intra- and extra-individual

factors. They also introduced an interesting distinction between intrinsic disablement and

actual disablement5. They described this distinction as follows: ‘Personal assistance and

special equipment are common, efficacious interventions used to reduce the impact of

functional limitations on disability…….’ ‘The difference between a person’s intrinsic ability

(difficulty doing Activity X without personal or equipment assistance) vs actual ability

5 This distinction brings to mind the subsequent distinction between capacity and performance, which is dealt with in the discussion about the ICF model.

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(difficulty with personal or equipment assistance) can be very great.’ The authors make some

example to clarify this: ‘For example, morning help to button clothing or special fasteners can

keep a person dress in ‘suitable’ manner for a high-profile executive job.’ ([7], 1994, page 8).

Also Verbrugge and Jette acknowledged the full role played by the social and physical

environment in the dynamics of disablement: ‘Disability can be alleviated at either side, by

increasing capability or reducing demand’ ([7], page 9). This way these authors underline the

role of the environment and launch the idea that interventions can affect two aspects: the

capabilities of a person, usually the focus of many rehabilitation actions, and the demands

made by the environment. The reduction in environmental demands can take place in different

ways:

• modifying activities in terms of their duration (how long), modality (how) and

target (what);

• modifying physical and social environments;

• psychological adaptation that becomes possible in the individual who gradually

accepts some symptoms and limitations, through personal paths (praying; a

redefinition of one’s targets and values) or through social paths (welfare). This

way these individuals develop a new definition of their own behaviours and of the

demands they make to themselves;

• external support, through personal care measures or welfare instruments that

operate very close to the individual, to the aim of curbing the demands made by

the environment or of increasing the capabilities of the individual.

A third revision of Nagi’s model was made in 1997 by Brandt and Pope of IOM ([4]).

They wondered whether disablement was an inevitable consequence of pathologies (on the

21

basis of the vicious circle of disablement), or whether this vicious circle could be broken to

activate a virtuous circle of enablement. A reference to enablement was already implicit in the

1991 model where both Nagi, and Pope and Tarlov had analyzed the various factors that may

influence the link between active pathology, impairment, functional limitation, and disability.

As early as 1991, the analysis of these factors had produced a list of biological, personal and

environmental factors that could be involved in the disablement process. The 1997 model

assumed that the same factors can be involved also in a process that reverses disablement (or

enablement). Various critical elements of the previous IOM model were listed, including:

- the disablement process being one-direction only, with an inexorable progression to

disability without any opportunity to reverse it;

- lower distinction among the environmental factors and of the interaction between the

individual and the environment, the latter being described in previous models only as

one of the risk factors in the links among the various domains of the main path;

- limited specification of social factors.

Taking these limits of the previous model into consideration, a new model was developed

that aimed at describing disablement as a consequence of the interaction between the

individual and the environment. The new model acquired three dimensions, i.e. the individual,

the environment and the interaction between the individual and the environment, wherefrom

disablement can ensue. As for the ‘individual’ dimension, it included the main path linking

pathology, impairment, functional limitation and non-disability. The links among the various

levels were identified by means of two-direction arrows, to point to the possibility of mutual

influences and to cancel the inevitability of the links among the various levels. Moreover if,

on the one hand, the disability level is cancelled, on the other the non-disability level is

22

introduced before pathology, to point out the starting point when functional limitations are

missing. Beside the main path risk factors were placed, which are here called transitional

factors to specify their role in causing a transition among the various levels and to point out

that there can be both disabling or risk factors (those that increase the likelihood that a person

has some functional limitations) and enabling factors (those that increase the likelihood that

the process does not start, that leads from a non-disability status to functional limitations). In

the ‘environment’ dimension, a distinction was made between the physical and the social-

psychological environments. Environment was compared to a sort of carpet or mat, the

strength or resistance of which is proportionate to the quality and the quantity of the support

systems and of the various barriers. The meeting between an individual, who has some

potentially disabling conditions, and the environment may give origin to a stronger or a

weaker disablement, depending whether the environment is more or less supportive or upon

the presence of many or few barriers (in the mat metaphor, this is represented by how deep

the person sinks into the mat). E.g. the absence of services and the presence of physical

barriers, discrimination, and the absence or the non availability of assistive technologies shall

cause higher disablement (and, therefore, the person shall sink deeper into the mat).

Therefore given equal impairments and/or functional limitations, there can be different

levels of disablement according to the relationship between the individual and the

environment. The physical environment includes buildings, transports, the weather,

technology, geographical and time location. The social-psychological environment includes:

discrimination, availability of health services, treatments, access to technology, culture,

employment, the family, economy, community organization, access to welfare services,

personality traits and factors, access to activities that promote health, attitudes and emotional

23

statuses, education, spirituality and independence. In the metaphor of the mat, each of these

social-psychological or physical factors represents one layer of the mat, the absence or the

lack of which causes the support to become weaker and entails some problems when the

individual interacts with the environment ([4], pages 71-72). It should be noted that while the

individual dimension features multiple links among its different levels (non disability,

pathology, impairment and functional limitation), some multiple links exist also between the

individual and the environment, therefore the environment can have a positive or a negative

influence on each level of the individual. E.g. the presence of an intervention aimed at

reducing spasticity can act on the impairment, while the presence of a customised mouse can

act on the functional limitation. A heart transplantation acts on the pathology level.

According to this model disablement is no longer part of the individual, but it is rather a

function of the interaction between the individual and the environment, a dependent variable

the value of which is calculated on the basis of the interaction between the two variables (the

individual and the environment) ([4], page 75). No doubt that to see disablement as the result

of the interaction between the individual and the environment is the original element in the

work made by IOM in 1997, as against previous contributions. Earlier in fact, though the

overlapping between pathology and disability had been overcome as was the fact of mixing

up the two terms, also the 1991 IOM model proposed a sort of inevitable link among these

terms: though mentioning the environment, it did not identify it explicitly as a determining

factor in the dynamics of disablement.

24

FROM THE CONSEQUENCES OF DISEASES TO HEALTH AND FUNCTIONING: THE

PATH FROM I.C.I.D.H. TO ICF

In parallel with the reviews of Nagi’s model and of the works by IOM, a major revision

process of the I.C.I.D.H. was undertaken ([18]). The first stage ended with the reissue of the

model in 1993 ([18]), and at that date a far-reaching study began that involved many groups

worldwide and the associations of environment-disabled people (who were invited to hearings

and to study groups) ([19]). The first step in the I.C.I.D.H. review process dating from the

1990’s was achieved with the publication of the Alpha version of I.C.I.D.H.-2, in May 1996,

and of the Beta version in April 1997. These were followed by translations in languages other

than English and by the Beta-2 version in 1999 ([20]).

Following debates on the I.C.I.D.H. revision process, another model was developed by a

group coordinated by Patrick Fougeyrollas ([21]). This model, now known as ‘Handicap

Creation Process’ (or “Processus de création du Handicap” in French-speaking countries), is

an interactive, anthropological, universal, person-environment interaction model by which the

author describes the role of environmental factors in the disablement process ([21-22]). The

dimensions analyzed in the model are risk factors, personal factors (related to organic

systems, functional capabilities and socio-cultural identities), environmental factors and life

habits (activities and social roles). The interaction between personal factors and

environmental factors may influence individual habits: it may foster full social participation,

(or create a situation of handicap to use the author’s words). The author describes a taxonomy

of environmental factors that includes social, cultural and physical dimensions of organization

and social context. This taxonomy embraces socio-economic organizations (family structure,

25

political systems), social roles (law, values and attitudes), nature (geography and the weather),

development (architecture and technology) ([21]).

As a result of the revision process of the I.C.I.D.H. and also of the influence of the models

developed at the same time - like the ‘Disability Creation Process’ - I.C.I.D.H.-2 introduced

the role of environmental factors, and also a new terminology on dimensions and the proposal

of a new title: International Classification of Functioning, Disability and Health. Lastly, in

2001, the Assembly of the World Health Organization (WHA resolution 54.21) proposed to

introduce a new model that was named International Classification of Functioning, Disability

and Health, or ICF ([2]). It is now published and used in 191 countries all over the world

([23]).

ICF defines health conditions and the states that associate to them. Health conditions are

defined as ‘an umbrella term for disease (acute or chronic), disorder, injury or trauma’, but

also ‘other circumstances such as pregnancy, ageing, stress, congenital anomaly, or genetic

predisposition’ ([2], page 212). To analyze health conditions and health-related states, the

model refers to two far-embracing terms: disablement and functioning. Disablement is the in-

teraction between the individual, with his/her health conditions, and the environment (in its

negative aspects), while functioning is the same interaction but in positive terms. ICF de-

scribes human functioning and its limitations as the result of the dynamic interaction between

health conditions and contextual factors. To this aim, some domains are analyzed and de-

scribed under the perspective of the body, the individual and society: respectively, body func-

tions, body structures, activities, and participation. Body functions are defined as ‘the

physiological functions of body systems (including psychological functions)’ ([2], page 12).

Body structures are ‘anatomical parts of the body such as organs, limbs and their components’

26

([2], page 12). Alterations in body structures and functions are called impairments. Moreover,

the model makes a classification of activities and of participation. Activity is defined as ‘the

execution of a task or action by an individual’ ([2], page 14). And this is how participation is

outlined: ‘involvement in a life situation’ ([2], page 14). They can both encounter problems

that are pointed out, respectively, as limitations of activities (‘difficulties an individual may

have in executing activities’) and restrictions in participation (‘problems an individual may

experience in involvement in life situations’) ([2], page 14). The distinction between activity

and participation is one of the least clear points in this new model, since there is only one

classification for both, although different options for distinction are suggested to the codifier.

The distinction between capacity and performance allows cancelling part of this ambiguity.

Capacity is meant as ‘the individual’s ability to execute a task or an action. This construct

aims to indicate the highest probable level of functioning that a person may reach in a given

domain at a given moment. To assess the full ability of the individual, one would need to have

a ‘standardized’ environment to neutralize the varying impact of different environments on

the ability of the individual’ ([2], page 15). How should this environment be organized? ‘This

standardized environment may be: (a) an actual environment commonly used for capacity as-

sessment in test settings; or (b) in cases where this is not possible, an assumed environment

which can be thought to have a uniform impact. This environment can be called a ‘uniform’

or ‘standard’ environment’ ([2], page 15). This way, authors mean that capacity reflects an in-

dividual’s ability, which is adapted according to the environment where such a capacity is be-

ing measured. On the basis of this distinction, it should be possible to assess the capabilities

of people who belong to different places and cultures, and international parallels could be

possible too. Performance is defined as ‘what an individual does in his or her current environ-

27

ment. Because the current environment includes a societal context, performance can also be

understood as "involvement in a life situation" or "the lived experience" of people in the actu-

al context in which they live’ ([2], page 15). Once again, details on the context are given:

‘This context includes the environmental factors – all aspects of the physical, social and atti-

tudinal world which can be coded using the Environmental Factors component’ ([2], page

15). The gap between capacity and performance is the impact of the environment and it can

provide some useful information on the intervention that is liable to modify the environment

and, thus, improve performance. So far we have described the domains of the health condi-

tions of an individual, but the ICF model analyzes the relationship between the individual and

the environment. This is why the second part of the ICF describes contextual factors, which

are divided into personal and environmental ones.

Contextual factors are defined as ‘the complete background of an individual’s life and

living’ ([2], page 16). Environmental factors are meant as: ‘the physical, social and attitudinal

environment in which people live and conduct their lives’ ([2], page 10). What role do these

factors play? They represent all that surrounds a person and that may have some influence on

the functioning of the individual and, therefore, on his/her body structures and functions, on

his/her capabilities (as an individual or as a member of a social group). These influences can

be positive or negative, depending whether these factors operate as facilitators or as barriers

(and this is exactly how these are described in the ICF model).

As already written above, ICF defines disablement as the result of the interaction among

the domains of body, individual, and environment. Undoubtedly, the theoretical contribution

that lies at the base of ICF received direct and indirect influences from the other models that

have been described so far, and it is the most recent one (and the most widespread, too).

28

However this model is clear only in part, both from the viewpoint of disablement and when

compared to the other contributions described so far (e.g., the one developed in 1997 at IOM

([4]) that explains the responsibilities of the environment in the processes of enablement and

disablement through the mat metaphor).

SOME HINTS ON THE EVOLUTION OF THE SOCIAL MODEL OF DISABLEMENT

So far we have described the progressive evolution of some conceptual models of

disablement developed at a national or international level, so as to specify some criteria for

eligibility to forms of individual support (economic, welfare, school, work, etc.). This analysis

neglected, temporarily, the conceptual contributions developed by the movements for the

recognition of the rights of environment-disabled people. The fact of neglecting it does not

mean that this field experienced no evolution. In fact, material evolutions were recorded.

On the one hand, this field too progressively assimilated the social model of

disablement through the work of its propounders, both in the wider social context and in

academic settings. Many experts in the field were busy disseminating it in universities, setting

up specific courses, creating magazines to publish contributions on the topic and organizing

scientific congresses. Some contacts were also made with the organizations that developed

international classification models. E.g. the wording of the ICF included, albeit not fully,

some instances of the social model of disablement.

Some internal revision processes were undertaken as well, which are characterised by

more or less responsibility being bestowed upon the environment during the process of

people’s disablement, or by a stronger or weaker desire to take different viewpoints into

29

consideration, also in comparison with the medical models of disablement. A signal of this

progressive opening is the fact that there is now a wider drive to consider the ‘social

interpretations of disablement’, both to suggest the manifold approaches that belong to the

social model of disablement ([15]), and to point to conceptual variations. This originated a

debate aimed at devising potential alternatives to the social model.

CONCLUSIONS

This paper tried to reconstruct the path of ideas that favoured the development of the

disablement models of the Twentieth century. These models defined the meaning of terms we

use everyday, and that do not always exert a positive effect for the people they refer to. The

development of these models took place concomitantly with the general development of ideas

and concepts on health; they influenced – and, in turn, were influenced by – the social setting

they belonged to. Some of these models were given higher visibility, though their level of

development was not higher or more original. At present we do not believe that there is a

clearer picture of the mutual relations among the models, of the correct historical direction

taken by these ideas, nor of the degree of dependence linking them one to the other. More

specifically, it is hard to detect the degree of mutual awareness in the different groups or in

the individual scholars who were busy developing the models described in this work. As for

the now predominant model, developed by several people, the feeling is that it does not enjoy

full conceptual homogeneity. To our opinion the ICF model is not very clear on the practical

translation of its essential theoretical choice: i.e. to see disablement as a dynamic process, the

‘here and now’ that happens when personal characteristics collide with socio-environmental

30

ones, rather than as a personal feature. The problems and the limits in this translation may

derive from its being the result of a multi-disciplinary model instead of a trans-disciplinary

one: as already specified in some other criticism, this essential choice was lost in the creation

of the classificatory taxonomies, which contain a better detailed classification of functional

and structural limitations, but a less detailed classification of activities, participation and

environmental factors. Moreover they analyse but partially the links among such factors (see,

for example, [24-26]). To our opinion it seems that a potentially good conceptualization may

not correspond to a practical translation of this conceptualization, in which we see a potential

regression that could negatively influence the analysis of the disablement process, and make

people more prone to see functioning as an individual responsibility (deriving from functional

and structural characteristics) instead of as an individual-environment interaction

responsability.

The choice to see disablement as a dynamic process is instead clearer and more

detailed in other models, like Nagi’s, Fougeyrollas’s and the 1997 IOM model by Brandt and

Pope. These other models describe in a better way the relationship between person and

environment in the creation of the disablement process, identifying a third dimension of the

relationship: the inter-relation between the first two. This dimension is clearer in the 1997

IOM model, but it is implicitly presented in the other two models, too. To see three

dimensions of the disablement process makes the dynamicity of the disablement process

clearer and shares the responsibility for the process among the other dimensions.

The problem is that these models contain only partially known practical classification,

while ICF is now used and known worldwide. A further analysis and conceptual clarification

of the ICF is needed to clarify the concept of functioning and its link with environment and

31

personal characteristics, to identify the previous three dimensions (the individual, the

environment and the individual-environment interaction), to clarify the role played by all

three dimensions within the process of disablement and to explore ways by which the virtuous

processes of enablement can be created ([27]).

ACKNOWLEDGEMENTS

The authors wish to thank Prof. Saad Nagi for the articles he sent and for the precious sugges-

tions he gave, Prof. Elisabeth Badley, Prof. Lois Verbrugge and Prof. Alan Jette for the art-

icles they sent. They also thank Vittoria Rubino and Andrea Petretto for their help in the Eng-

lish editing and two anonymous referees for their useful suggestions on an earlier version of

this paper.

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