rehabilitation: an ergonomic dimension

International Journal of lndustnal Ergonomws, 9 (1992) 97-108 97 Elsevier

Rehabilitation: An ergonomic dimension

Shrawan Kumar Dept of Physical Therapy, Unwerstty of Alberta, Edmonton, Alberta T6G 2G4, Canada

(Received date April 18, 1991; accepted in revised form November 20, 1991)

Abstract

The dissimilarities between rehabilitation and ergonomics, due to differences between thexr clientele, have caused a perception of exaggerated divergence. Through a discussion of their components and a conceptual analysis of their processes, rehablhtatlon and ergonomics have been tied together. It has been argued that incorporation of ergonomic philosophy, content and methodology will enhance rehabdltatlon. Due to the ever-increasing population of the disabled and the aged, the demography of the workers is changing worldwide A framework of operationahzlng the incorporaUon of ergonomics in rehabilitation is presented to provide an appropriate accommodation for the disabled and enlarge the human resource pool for the industry A position has been taken that rehabihtatlon is ergonomics' remaining responsibility.

Relevance to industry

The disabled population is changing the characteristics of the workforce. The arguments and scheme presented here wdl assist an efficient and productive integration of the disabled m the workforce. The paper thus identifies an area of industrially relevant ergonomic growth.

Keywords

Rehabilitation, ergonomics, functional evaluation, job accommodation

Introduction

The suggestion that rehabilitation is an ergonomic dimension may be contrary to mainstream ergonomic belief. Ergonomists have developed normative data on many aspects of human structure, function, and behaviour for many decades. This had been a pressing necessity to feed the medical model. A normal 'standard' or 'reference' is essential to gauge the decrement for remediation. These reference points have also played a valuable role in the quantification and understanding of super-normal physical, physiological or behavioral achievements. Such an en- trenched 'normal' performance standard has been rightly chosen as design criteria in ergonomic endeavors. These latter criteria have been used in

the design of tasks, work environments, jobs, products, production quota, activities of daily living, and recreational activities. Since ergonomists have worked with these standards, anything else may be considered running against the ergonomic grain.

However, Grail (1979) reported that in the United States alone, the total estimated number of people considered handicapped was 62.3 million - 30% of the US population. Within this group his evidence suggested that 49 million people were permanently disabled and handicapped. This population was also 30% older than the non-handicapped and at least three times more likely to be unemployed. The Disability Statistics Compendium (United Nations 1990) reported disability in other countries to range between

0169-1936/92/$05.00 © 1992 - Elsevier Science Publishers B.V. All rights reserved

98 S Kumar / Rehabthtatton An ergonomlc dimension

Table 1

DlsaNhty reported in various countries around the world

Country Year Ages % Dis- abled

Australia 1981 all ages 13 2 Austria 1976 all ages 20 9 Canada 1986 all ages 13 2 China 1987 all ages 4.9 Japan 1980 18 yrs and over 2.4 Nepal 1980 all ages 3.0 Phlhppmes 1980 all ages 4.4 Spain 1986 all ages 15 0 United Kingdom 1985-86 0-15 years 3 2 United Kingdom 1985-86 16 yrs and over 14 2

2.4% to 20.9% of the total population. A partial listing of the reported disability is provided in table 1.

Due to a lack of standardization in process, criteria and reporting, the number of people who fall under the disabled category have been grossly underestimated. For the reasons of underreport- ing and a lack of useful data on the disabled, the technological development has been intrinsically geared to cater only for mainstream society and leave out the special groups. It is, however, worth noting that with increase in age the disabdity increases (United Nations, 1990), and the life expectancy is also on the rise. Furthermore, in the North American continent especially, it is projected that by the year 2010 up to 40% of the overall population would be above 65 years old. In spite of the overlap, the combination of disabled and older population (functionally subnor- mal) will tend to tip the balance away from the conventional normal population. It is therefore a matter of considerable urgency that an appropriate and balanced redirection of ergonomic efforts must be initiated and nurtured today to meet the need of tomorrow (and also today) of impaired, disabled and handicapped citizens, consumers and workers. A reconsideration of emphasis and allocation of proportionate and commensurate attention and resources is essential.

The purpose of this paper is to rationalize the commonality between and the parallelism in evo- lutionary paths of ergonomics and rehabilitation. Furthermore, it is intended to bring the changing ergonomic need into focus; and present a scheme of operationalizing the incorporation of er-

gonomics in important people, processes and product-related ergonomic considerations in the rehabilitation arena.

Disability context

The description and understanding of the term and concept of disability is somewhat obscured by non-standardized usage. Conceptually, disability is a reduced functional status resulting from an impairment and giving rise to a handicap. These terms according to the International Classifica- tion of Impairments, Disabilities and Handicaps (ICIDH) proposed by the WHO (1980) are as follows: - Impairment: 'Any loss or abnormality of psy-

chological and anatomical structure or function'. Therefore, impairments are disturbances at the level of the organ which include damage or loss in part or whole of a body part or member, as well as derangement or loss of mental function.

- Disabdity: 'A restriction or lack of ability (re- suiting from impairment) to perform an activity in the manner or wtthm the range considered normal for a human being'. Therefore, a disability is a functional limitation or activity restriction, probably caused by an impairment.

- Handicap: 'A disadvantage for a given indivM- ual, resulting from an impairment or disability that limits or prevents the fulfilment of a role that is normal (dependmg on age, sex and social and cultural factors) for that individual'. Thus, the term handicap describes the situation of nonfulfillment of social and economic roles of disabled people which depending on circumstances, environment and culture would be normal for others to do. From the functional point of view then, Kumar

(1989) argued that most people are disabled to some extent in one or more of the multitude of functions one performs. The reference is taken from, in such determinations, the normative data which are obtained from a large group of normal people. The scale of functioning is presented in figure 1. Strictly speaking then, all functions which one is capable of must fall within this range. However, for any given individual the extent of a disability and handicap may be dependent on the

S Kumar / Rehabthtattom An ergonornw dtmenslon

Elite Atheletic Ability

Super-Normal

Normal

Sub-Normal

Impaired

Disabled

Fig 1 Abdlty-dlsablhty continuum

I Prevention

I World Program l

of Action

J ",,, Fig 2 World program of action

99

prevention, rehabilitation and equalization (figure 2).

The ergonomic dimension

hierarchy and frequency of use of the given function.

Coping medical and health model

The inevitability of impairment, ensuing disability and handicap assured by statistical law of averages has become a fact of life of our socio- economic structure. The World Health Organiza- tion in its World Program of Action has identified three goals to cope with the problem. First is the primary prevention. It is to be accomplished by measures aimed at preventing the onset of mental, physical and sensory impairments. If an impairment has occurred, then negative physical, psychological and social consequences can be minimized or eliminated. The second goal is rehabilitation. A goal-oriented and time-limited process aimed at enabling an impaired person to reach optimal mental, physical and social functional level is put in place. Of course, the process in addition to being enabling, also strives to reduce and eliminate pain and suffering. The third and final goal is equalization of opportunities for handicapped people. This involves a process through which physical environment, housing and transportation, social and health services, educa- tional and work opportunities, cultural and social life, including sports and recreational facilities, are made accessible to all. Thus, the coping medical and health model has the tripartite goals of

The dual complimentary emphases of ergonomics are placed on the worker and the work. Work is not only important but, in this context, is the ultimate objective. The 'end' of work is achieved through the 'means' of worker. There- fore, the worker by the logic of hierarchy, technical and social considerations becomes the most important component and strategic focal point for technological considerations. A comfortable, healthy and well adjusted worker is more likely to be a motivated worker with high morale. Such a combination of factors is generally known to translate into high productivity and better industrial relations. Thus, the complementarity of these dual foci has a tendency to establish and optimise the gain of a self-amplifying loop. Under unfavor- able circumstance the converse is also likely to happen (figure 3).

~ ~ Opt .n.mse

\ c r onom,cs F~g. 3. Interdependence of dual focl of ergonomics.

100 S. Kumar / Rehabthtatton: An ergonomtc dtmenston

Thus, not only are the tripartite goals of ergonomics mutually complimentary in influencing the outcome measure significantly, but they are parallel to and compatible with the tripartite goals of the coping medical and health model. The complementarity between the prevention of impairment and the comfort of worker, rehabilitation of disability and health and safety, and equalization of disability and health and safety, and equalization of opportunity and efficiency and effectiveness are obvious. Ensuring the comfort and wellbeing of the workers through hazard identification and their elimination from the work place will accomplish the public health goal of prevention of impairment thereby eliminating the need of rehabilitation. Such a step is likely to optimize productivity, enhance worker morale and reduce labour turnover. These are strategically significant in economic terms for industry and good for the morale and loyalty of workers. From these emerge better and stable industrial relations. In order to achieve this the task at hand is ergonomically fitted to the worker. Given the worker characteristic - normal or impaired, the process of fitting the job through adjustment or modification to maximize worker capability is ergonomics and parallel to the process of disability rehabilitation of the medical and health model. The ergonomic principle of enhancing efficiency and effectiveness is complimentary to the equalization of opportunity which seeks to enhance environmental accessibility to disabled people through reduction in demand.

Ergonomics, however, is not only complimentary to the medical and health model but can be

r~

Super Normal

Congemtal

Congenital

(a)

~ e r ~ q .ben

N d a p t e ~ ~ training

an effective tool in the realization of its goals. Impairment prevention can be achieved to a large extent through hazard elimination. The process of rehabilitation can be significantly enhanced by incorporation of ergonomics in treatment and management strategies. The role of ergonomics lies not only in provision of normative standards but also in the development of testing and evaluation techniques. The latter provide quantitative measures of success. Furthermore, ergonomics can offer meaningful enhancements of treatment regimes. In the final stage of management with equalization of opportunity the role of ergonomics is prevalent, pervasive and extensive. In fact, the equalization of opportunities can be delivered only through the medium of ergonomics. The role of ergonomics integrated in the medical and health model is represented in figure 4a and b.

The complementarity

Kumar (1989) defined rehabilitation as follows: 'Rehabilitation is a science of systematic multidimensional study of disordered human neuro-psycho-social and / or musculoskeletal function (s) and its (their) remediation by physico-chemical and~or psycho-social means'. Ergonomics, on the other hand, is defined as 'the natural laws governmg work'. If one were to discount the qualifier of 'disordered' from the definition of the rehabilitation and consider activities of daily living as work, then the definition of ergonomics is entirely applicable to rehabilitation. From the previously

D.

Super . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . So~ (b)

.... i . . . . . . . . . . . . . . . . . . .L 13 12

Events m Tnne

Fig 4. (a) Congenital and adapted performance endowment. (b) Generic outcome of normal performance endowment subjected to interventions of impairment, rehabdltatnon, and enhancement through ergonomics. 11 - injury and impairment, 12 - rehabdxtatton,

13 - j o b mo&ficatlon, 14 - asslstwe dev]ce

S Kumar / Rehablhtatton: An ergonomw &menslon 101

mentioned description of the tripartite goals of both disciplines and the foregoing definitions the commonality of these two sciences is obvious. The central goal of both disciplines is to enable, enhance and optimize function. The difference lies in the context and clientele.

While rehabilitation is involved in disability prevention, functional restoration and deficit compensation among clients who have suffered impairment, ergonomics endeavours to increase efficiency and effectiveness by tapping the maximum possible from the pool of resources of a normal individual. The enhancements and adap- tations are made in environment or man/ma- chine interface to optimize the human capability. Therefore, both these disciplines are involved in maximizing the outcome; however, in different regions of the ability scale. This scale difference serves to artificially exaggerate the appearance of divergence. The comparison of these two disciplines is presented in table 2. Though these two disciplines have shared goals, rehabilitation is concerned primarily with functional independence especially for activities of daily living. Er- gonomics on the other hand, while maintaining comfort, safety and health of workers, strives to maximize industrial productivity.

Both rehabilitation and ergonomics have drawn their components and building blocks from the same branches of basic and applied sciences. These, however, have been integrated differently among these disciplines which portray different pictures. Nonetheless, both these disciplines are

Table 2

Rehabilitation and ergonomics compared.

Rehablhtation Ergonomics

Health promotton Disability prevention Dysfunction prevention Reheve pain Functtonal restoratton Skill development Environmental adaptation Deficit compensation by

augmentative devices Sooal adjustment through

counselhng

Ensure comfort Maintain well being Hazard reduction/elimination Avoid pare Achieve effectweness Training Job modification Enabhng devlces and

adjustments Industrial relations

Rehabilitation Ergonomics

Fig. 5 Overlap and commonality between rehabdltatlon and ergonomics.

multidisciplinary, deriving generously from physical sciences, life sciences, behavioral sciences, biomechanics and kinesiology. Thus, identical goals, reliance on the same constituent disciplines, and working toward enhancing and opti- mizing human function depicts the extent of overlap between these two disciplines (figure 5). Vari- ous ergonomic concepts and practices interweave through the rehabilitation fabric imperceptibly. It is emphasized here that a more structured and integrated approach will enhance and enrich rehabilitation. On the other hand, making such a considered and concerted effort will enhance and enrich ergonomics as well. Furthermore, a position is taken here that rehabilitation is ergonomics' remaining and ultimate responsibility. Considering the current significant size of the disabled population in North America and around the world and the ever increasing proportion of older people in the workforce and society, this argument does not need further elaboration.

Despite a large overlap and significant complementarity between rehabilitation and ergonomics, it will be misleading not to indicate their essential differences. In addition to the context and clientele, their differences lie in the specific body of knowledge, rehabilitation being clinical and ergonomics non-clinical and applied. Furthermore, the ergonomists work toward adjusting and optim- izing factors external to workers to enhance comfort, wellbeing, efficiency and effectiveness. The rehabilitation professionals, on the other hand, work primarily toward enhancing the factors internal to workers for functional restoration. The residual dysfunction is then dealt with through augmentative devices.

102 S Kumar / Rehabthtatton An ergonomtc dtmenston

Operat ional blueprint

With the increasing size of the special population which needs services spanning the traditional territories of rehabilitation and ergonomics, and the intrinsic commonality with overlap between these disciplines, it is a matter of some urgency to develop a plan to operationalize the integrated execution to meet the social needs. In any such activity multiple levels of effort will be necessary. In order to adequately cover most circumstances functional dwisions are necessary. Some considerations will be more appropriate for people, others for processes and still others for products. A brief discussion ensues in that order.

~ I E . . . . . . . d I ITra~ i"~ I ~

/ I CO)qVENTI/ONAL \

~, REHABILITATION /

Rehabdltatmn ~ Counsdhng and ~ ~ ISocmlSupp oft

/ , ERGOMONIC \ Mu tmdlmensional * \ Funchonal ~ Functmonal ~ Job Redesign and

I A . . . . t I ] / I [ [ Augmentatmn

CONTENT /

' ' ~ Hardening

Fig 6 Componen t mte rachon m hollstlc rehabdltat lon

People related

In the functional domain a clear establishment of multifaceted quantitative norms of various human activities is an essential starting point. A direct transfer of information generated in numerous studies which dwell on unidimensional performance In athletic activities is not relevant. Firstly, these levels of activities cannot be sustained on a long-term basis due to their intensity. Secondly, their influence on other variables which may also be required in operation (to a varying degree) will not be known. Furthermore, these studies use people who excel in these activities incorporating an elite bias. It is therefore essential to have multidimensional functional evaluation norms of normal and average people of both sexes and different age groups. Such an endeavour will allow us to determine the gender and age factors of ready adjustment in a given population. Such an extensive data base, though tedious to develop, will serve as a three-dimensional framework to base functional assessment to determine the nature and extent of functional deficiencies and impairments. One such database has been developed and reported by Kumar (1991). These will also provide a goal for treatment planning and a continuous comparison to determine any progress or remaining deficiency, as the case may be. Thus, the nature and extent of functional impairment and subsequent recovery when deter- mined multidimensionally (in all relevant criteria) will assist holistic rehabilitation (Kumar, 1989). Commonly patients are released only after partial

rehabilitation (barely functional for activities of daily living) and are not followed to their work places. Not only philosophically, but pragmati- cally it is emphasized that rehabilitation is incom- plete unless the patient is relntegrated in the work force with or without adjustment a n d / o r augmentation. The independence of a patient is not limited to physical partial functions, but also economic independence and social adjustment. A disregard for such a holistic rehabilitation may recur significant cost to the society, lost productivity to the economy and adverse social and psychological impact on the patient. Only a concurrent broadening of scope of ergonomics and rehabilitation and their overlapping application can result in holistic rehabilitation (figure 6).

Physical work-worthiness. An impairment is a perturbation which adversely affects function. An individual with an impairment, during the course of daily living and daily work, will perform a multitude of activities involving numerous physical traits. Due to interdependence of physical traits and the dependence of more than one trait on one physical or physiological parameter, the functional aberration is likely to be variable in multiple dimensions. In order to maintain normal performance one will have to have normal range of motion, strength, endurance, kinematics, kinet- ics, perception and motor coordination. A physical injury causing pain may affect more than one variable in varying amounts, resulting in an entirely different picture compared to pre-injury state. Therefore, physical work-worthiness must

Flexion

Adduction Abduction

S Kumar / Rehabthtatton An ergonomtc dimension 103

Extension

Fig 7 A quantitative pictorial depiction of available motion among joints with two-dimensional motion capablhty

be rated multidimensionally incorporating all relevant variables. The traditional medical model of rehabilitation generally based the rehabilitation decisions heavily on range of motion. Such a practice would be considered sound if the range of motion was the sole variable required to be functional. No useful and productive work can be done just by moving body parts. Generally, force application is also essential. Thus, testing of motion for the available range may be the first necessary step (figures 7 and 8). Having deter- mined the required motion for a given task it will be essential to determine the maximum strength required to carry out the task in question. Due to the concurrent requirement of range of motion and strength the job requirement can be presented as in figure 9. Productive work environment has a constant demand of pacing and/or output. Therefore, the speed of activity with re-

Flexion 13o

Internal / 12o External Rotation J ~ Rotation

loo so

70 DEFICIT 70 70 0

AVJ t LABLE

I

Adducbon Abdncbon 50 a0 20 10 2 ~ 1 0 20 3O S0

Extensloll Fig. 8 A quantitative pictorial depiction of available motion, and motion deficit among joints with three-dimensional mo-

tion capability

180

P 15o

120

"~ 90

"~ 60

e~ 30

o

Required

Available

. 11~ 200 300

Strength in Newtons

400 50o

Fig 9 Range of motion and strength required to do a given job

quired strength within the established range of motion also becomes an essential criterion. Si- multaneous consideration of all three factors can provide a complete picture of job requirements (figure 10). An overlap of the patient capability on the job requirement profile will be essential for a quantitative functional assessment and de- termination of deficiencies. The difference between the boundary lines of job requirement and availability in the patient will be a quantitative measure of deficiency due to impairment for one task cycle. Other physical and physiological variables such as endurance, cardiopulmonary fitness, aerobic capacity, dexterity, precision, tissue tolerance characteristics and status of pain will all determine full physical work-worthiness. All of these physical traits will be demanded for work- worthiness due to the repetitive nature of productive industrial work (figure 11). An interaction between the production quota and reasonable

Range of Motion

I

Availabl

~ Requtred

Speed

Y / ~ Strength

Fig 10 Physical traits required for a task and patient capabll - ity.

104 S Kumar / Rehabihtatton. An ergonomlc dimension

Strength S p e e d Dexterity Precision

Range l Physical ce of Work-worthiness

Motion Vascular

Fitness

Pain Tissue Aerobic Tolerance Capacity

Fig 11 Major physical traits reqmred for physical work- worthiness

human performance capability will determine the frequency of operation and the shift duration.

Psychosocial work-worthiness. A similar multidimensional requirement in psychosocial domain is essential for optimal functioning of the worker (figure 12). For final assessment the patient will have to be quantitatively tested on all affected relevant variables. The decision of further treatment, training or returning to work will significantly depend on the job demand. It will be only through, preferably, a quantitative overlap of the patient's physical and psychosocial capability over the job requirement that an ergonomically trained rehabilitation professional will be able to determine the shortfall and select a strategy to manage (figure 13). This imaginary task requires a great deal of speed, precision, dexterity, perception, cognition and fast reaction time. On these criteria the hypothetical patient has deficiencies and is, at the time of assessment, unsuitable to be sent back to this job. A similar deficiency hence incompati- bility could be found in physical domain. Under these two sets of conditions different decisions

Decision Reaction Integrative Making Time Judgement \ /o__n co,o.,o° j

Perception ~ Psycho-social ~ Fat,R.,, Work-worthiness

Peer-acceptance Motivation

Task comnntment Confidence Drive

Goal orientation

Fig 12 Major psychosooal traits for optimal work-worthiness

Integrative ~.A Aerobic Judgement

• "~ Capirdtiy -- / Decision ~ Endurance ~ / / Making " ~

-~ Precision " ~ ~ ~ ' D~ ~ ~ Operation .

[ Dexterity ~F//////~ 1 ]

\ . . × Motion/ \ Sel? cceptance / X

~ . / Task Drive Goal Esteem i o=-:°-S/ ~ Social r

Fig. 13. A conceptual model of holisUc comparison of patients' capabihty B and job requirement A.

will be made for divergently different rehabilitation strategies. Furthermore, a comparison of patients with normative data on all these scales will help determine quantitative functional Impair- ment or disability, as the case may be.

Process related

Subsequent to the rehabilitation effort many patients are left with residual functional impairment which may inhibit their being gainfully employed. In Canada, almost one half (45.6%) of all disabled people required assistance in performing heavy household chores, while nearly one quarter required assistance to perform daily housework (22.4%) or to shop (23.2%) (Statistics Canada, 1990). In many cases disability impact is com- pounded due to many people having more than one disability. Statistics Canada (1990) reported that though mobility and agility are the most common disabilities at 64.4% and 55% respec- tively, hearing, mental and visual disabilities ranked at 30.8%, 27.3% and 16% in that order. It is also reported that only 40.3% of all disabled persons of working age were gainfully employed in Canada in contrast to 66.6% of the general population (Statistics Canada, 1990).

To enable people with disabilities the first and foremost attention has to be given to job redesign in light of the quantitative functional assessment,

s. Kumar / Rehabditatton An ergonomtc dtmenston 105

as detailed before. To a disabled worker, the components of the job demand falling beyond the person's capability have to be modified to bring the job within the worker's capability. Such job accommodation most frequently may involve modification of hardware as well as the processes. For now, until the categories of generic disabilities along with magnitude of gradations are established, these may have to be dealt with on a case by case basis. In some cases a job redesign may not be sufficient to enable a disabled worker. Enablement may require an assistive or augmentative device. Such a strategy may also be found effective among cases with minor disability, where assistive devices may circumvent a need for hardware modification. Such a strategy of flexible matching with varying extent of job modification and assistive device will not only give the disabled person a sense of self-worth, but also increase the gross national product.

Assistive devices may range from a simple cane to sophisticated robots. Disabled people require personal attention and care. These individuals rely on family members, friends, or attendants for their daily needs and for mobility. The largest cost for these people is not medical care but maintenance, attendant care, nursing home, and home care expenses on top of loss of productivity due to inability to work. Assistive devices offer disabled people a chance to decrease these costs and function more effectively in the society by performing the processes which they otherwise could not. It is revealing to note that in 1980 in the United States, over 3,000 times as much money was spent on people and equipment to care for the disabled than was spent on development of technology that would allow the disabled to care for themselves - $220 billion versus $66 million (McNeal, 1982). LeBlanc and Leifer (1982) also reported that the money spent on the technology of assistive devices was economically bene- ficial to the society. They stated that every dollar spent on assistive device technology returned $11 in benefit to the society.

Gilbert et al. (1987) reported development of a robot mannequin with 38 degrees of freedom in movement to test the effectiveness of protective clothing in hazardous environment. This mannequin equipped with skin sensors had the ability to replicate ancillary biological systems including

sampling of chemical reagents which would be of immense value to a disabled worker with loss of tactile sense. NASA (1989) reported development of a device which may improve the vision of people with visual disability of low vision, which cannot be corrected medically, surgically, or with eye glasses. Such a restoration of visual function will allow execution of normal productive life. Tuchi et al. (1985) reported development of a robotic aid for the blind. This robot is designed to replicate the functions of a guide dog. It can be programmed with appropriate landmark information of an area and it has the capability to guide the owner to a desired destination. Such exam- ples clearly indicate that identification and quantification of a needed process or component of a task may allow development and fabrication of an augmentative device which may enable an otherwise disabled worker. It will, therefore, be of value to analyze many of the tasks in question ergonomically and develop an inventory of generic processes which may help many disabled individuals.

P r o d u c t re la ted

One of the important tenets of development of any product and its sustained success would be the ability of the market place to be able to support it. A continued state subsidy for such items spell their ultimate demise due to unafford- ability rather than lack of usefulness. At first sight the above statement may appear uncompas- sionate contrary to the motive of furtherance of this argument in the first place. If the initial design criteria take this fact into account, the products may last much longer on the market and benefit the disabled population. In exploring such a market the socio-economic statistics about disabled people is very pertinent. Statistics Canada (1990) states that only 40% of all disabled people are employed in Canada. Whereas up to 50% of disabled men are gainfully employed, only 30% of women with disability have employment. The Secretary of State of Canada (1990) states that over 57% of all persons with disability have an annual income less than $10,000. Grail (1979) reported that in the United States the chronically disabled were likely to have only one half of the income of non-handicapped and were twice as

106 S Kumar / Rehablhtatton An ergonomtc dtmenston

Table 3

Nature and seventy of disability by age group in Alberta

Dlsabdlty 15-64 years 65 years and over

Nature Total 155,725 73,160 Moblhty 92,250 56,495 Agdlty 80,980 49,775 Seeing 18,185 15,560 Hearing 36,655 30,210 Speakmg 9,905 3,835 Other 37,575 17,665 Unspecified 15,490 2,145

Secertty Mdd 82,220 26,170 Moderate 52,365 27,085 Severe 21,140 19,910

likely not to have health insurance. Disabled people were at least three times more likely to be unemployed. Furthermore, up to 30% of the American population was disabled. This clearly indicates that there is a large number of people needing special products with little money available. Any product developed for this market, therefore, has to be low cost for affordability reason.

Despite the inherent difficulties with the market there are many groups of people associated with disabled who will be secondary beneficiaries

of such availability and prove to be vocal and powerful advocates. These people will include physiatrists, orthopaedists, neurologists, cardiolo- gists, ophthalmologists and ENT specialists among medical professions. Almost the entire allied health profession including nurses, thera- pists, and rehabilitation engineers will also consti- tute a strong supporting group. Lastly, the family and friends of disabled people will also be indi- rect beneficiaries of such products in a big way. Of course, the manufacturers and suppliers will also have a vested interest in success of such an endeavour. Since such developments are likely to touch lives of so many, their consideration in depth is a technical as well as moral responsibility of ergonomists. Is the profession ready to deal with this challenge effectively?

In a Health and Activity Limitation survey the Alberta Bureau of Statistics (1989) and Statistics Canada (1990) have divided the disability types into a total of seven categories: mobility, agility, seeing, hearing, speaking, other and nature, not specified. The first two constituted the bulk of disabilities for Alberta (table 3). The United Na- tions (1990), in its international survey of disability, identified five broad issues: (a) presence of impairment, (b) presence of disabiliues, (c) causes of impairment, (d) social, economic and environment characteristics, and (e) distribution and use of services and support. For the current discus-

Table 4

Umted Natmn's classlficat~on of ~mpatrments.

Category Type Description

Physical (sensory) Aural Language Ocular

Visceral

Physical (other)

Intellectual and psychological

Generahzed sensory and others

Skeletal

Disfiguring

Intellectual and psychological

Auditory sensitivity Language functions and speech Visual acmty

Internal organs and impairments of other speoal functions, e g sexual, mastication and swallowing

Head and trunk regton, mechanical and motor impairments of hmbs and deficiencies of hmbs

Disfigurement of head and trunk, regions of hmbs

Intelhgence, memory, thinking consciousness, wakefulness, perception and attention, emotwe and vOhtlonal functions and behavlour patterns

S Kumar / Rehabthtatton An ergonomtc dimension

Table 5

United Nation's (1990) classification of disabilities.

107

Category Type Description

Physical (functioning) Locomotor Communication Personal care

Body disposition

Dexterity

Social functioning Behaviour Situational

Other

Ambulation and confining disabilities Speaking, listening Personal hygiene, dressing, feeding and excretion

Domestic disabilities, e g preparing and serving food and care of dependents, dlsablhtles of body movement, e g. fingering, gripping and holding

Skill in bodily movements, including manipulative skills and ability to regulate control mechanisms

Awareness and disabihtles in reactions Dependence and endurance and environmental disablhties relating to tolerance of environmental factor

Dlsablhtles of particular skills and other activity restrictions

sion presence of impairments and disabilities are most relevant and are presented in tables 4 and 5. A concurrence in classification, description, and definition of impairment and disability between different countries still appears to be a fair dis- tance away. A lack of commonality in classification and description of impairment and disability may be a formidable impediment in universaliza- tion of solutions. It may, therefore, be the necessary first step to develop a functional categoriza- tion regardless of cause and nature of impairment. The discipline of ergonomics is equipped to commence the development of a generic functional classification applicable across conditions which results in similar functional deficiencies. These criteria can then be incorporated in design and development of products for use by disabled

Work Conditioning Counselling Work Hardening / Job Modification

Psychological \ / / Job Accomodatlon Evaluation \ / /

\ \ / / / Imp ....... t/Disability ~,,n<,,ona, \ \ / / / ~ ' 0

Evaluation t \ \ / / / Assist . . . . . (Physical) ~ x \ ~ ¢/ J / Augmentative

J o b f i t t m g - ~ - - ~ R ~ b i l i t a t i o n ] / o~ .... Safe --------~l Ergonomics /' x ..... g

Pr,,,:t,,~. L ~ _ _ J " ' ~ / / t ~ N. ~ Function

Preventative / / / \ ~ Allocation R h . . . . / / \ ~ A . . . . tot

Cost-benefit / \ Effectivenes Analysts / \

Product Testing Product Design and Evaluation and Development

Fig 14 Components of rehabilitation ergonomics

consumers. Existing products considered suitable for use by disabled consumers can be tested against the criteria thus generated. Therefore, the scope of ergonomics can readily expand to include rehabilitation which in fact is a legiti- mate, though relatively unexplored dimension. Thus, rehabilitation ergonomics may be considered to consist of components as shown in figure 14. An extensive need for a category of product universally needed by disabled people lS appropriate clothing. Some creativity and innovation in this area can go a long way to make life so much easier for all concerned. An eff ioent functioning of disabled population is not only a moral nicety, but an economic necessity in newly emerging reality of life. Are we ready to face the challenge?

References

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rehabilitation: an ergonomic dimension

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