1. Measurements of Disability
Definitions and basic concepts:
Aggregate measures of disability:
2. Social attitudes towards disability
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Note: This page outlines some current phrasing in speaking of persons with disabilities as well as older terms that are still in use. Both are important to know.
Historically, there was confusion about the meaning of terms such as "impairment", "disability" and "handicap". In 1976, the WHO created the "International Classification of Impairments, Disabilities and Handicaps" (ICIDH) in which these terms were defined. While they all refer to different levels of the consequences of disease, the context of the individual affects the final impact.
Impairment was defined as "any loss or abnormality of psychological, physiological, or anatomical structure or function." Impairment is a deviation from normal organ function; it may be visible or invisible
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." An impairment does not necessarily lead to a disability, for the impairment may be corrected.
In turn, Handicap was defined as "a disadvantage for a given individual, resulting from an impairment or a disability, that limits or prevents the fulfillment of a role that is normal (depending on age, sex, and social and cultural factors) for that individual." Handicap considers the person's participation in their social context.
The WHO revised its Impairment, Disability and Handicap triad in 2001, re-naming it the International Classification of Function (ICF). This contemporary conception of disability views it as an umbrella term for impairments, activity limitations and participation restrictions.
The ICIDH’s "Impairments" "Disability" and "Handicap" are analogous to the ICF’s "Impairments", "Activity limitation" and "Participation restriction".
The ICF represents a shift toward more inclusive, positive language. It views function as an interaction between an individual’s health (including a disease or injury) and the context in which the individual lives (including physical environment and cultural norms relevant to the disease).
Quality of life: "An essentially subjective judgment of the way people perceive themselves as contented and happy or otherwise, and able to function physically, emotionally, and socially" - J. Last, Dictionary of Public Health, 2007.
Starting in the 1980s, clinicians began to tackle the challenge of how to describe the goals of medicine when a disease could not be cured, beyond merely controlling symptoms.
The notion of quality of life gained prominence as a way to emphasize a positive perspective on health - enhancing a person's capacity to function and to live, even if the person has an incurable condition. A central aim of care was to enhance the quality of the patient's function, and hence their ability to life as normal a life as possible, even if the disorder could not be cured.
Quality of life was a further extension of participation restriction or handicap, covering maintenance of normal function, but adding psychological well-being, plus positive feelings of engagement, or having a purpose in life and the ability to enjoy the possibilities that their life brings. Quality of life is an inherently subjective concept, to be judged by the person themselves.
Measurements of quality of life extend the disability focus beyond the ability to perform activities of daily living to include a broad range of functioning (work, home, play) and also the person's feelings of satisfaction and well-being. This is a qualitative concept, judged by the patient in terms of the extent to which they are able to do the things they wish to do.
In the medical context, we refer to "Health-related quality of life" which is distinct from wealth or possessions, which form aspects of material quality of life that are not considered and relevant as outcomes of care.
Conceptualizing disability in the Disease-Illness-Sickness triad
This diagram suggests possible parallels between the impairment, disability & handicap triad, and the disease, illness and sickness triad. (The squiggly arrows are intended to indicate a rough correspondence).
Physical impairments can be accurately assessed, but they are not the only factor that predicts a patient's need for care: environmental factors, the availability of social support and the patient's determination all affect how far an impairment will be translated into disability or handicap. Hence, for evaluating patient rehabilitation, we need measures of disability and handicap or participation as well.
Activities of Daily Living (ADL): Based on Sidney Katz's 1957 Index of Independence in Activities of Daily Living, ADL assessment summarizes a patient’s degree of independence in bathing, dressing, using the toilet, eating and moving around the ward – topics that Katz chose to represent "primary biological functions."
The results can be presented as a single score, or as a profile of the level of function in each area covered. There are now many such measures, each giving the clinician (or researcher) guidelines on completing the assessment; many can be completed by the patient themselves via a questionnaire.
Instrumental Activities of Daily Living: In 1969, Lawton and Brody extended the ADL concept to consider problems more typically experienced by those living in the community: mobility, difficulty in shopping, cooking, or managing money, a field that came to be termed "Instrumental Activities of Daily Living" (IADL) or "Performance Activities of Daily Living" (PADL). Instrumental activities are more complex and demanding than basic ADLs; they offer indicators of applied problems that include elements of the handicap concept. They are relevant in assessing a patient's ability to live independently in the community.
Distinguishing Capacity from Performance
You may wish to distinguish between a person's physical capacity and his actual performance in managing his life in the face of physical limitations. There are two ways of phrasing questions on functional disability: you can ask what the patient can do (the "capacity" wording) or what she does do ("performance" wording). Both hold advantages and disadvantages. Asking what a patient can do may provide a hypothetical answer - what she thinks she could do even though she does not normally attempt it. This phrasing can exaggerate the healthiness of the respondent, perhaps by as much as 20%. The performance wording may run the opposite risk: performance may be restricted by factors other than health, so performance questions may under-estimate potential. An intermediate phrasing can be used, such as "Do you have difficulty with . . .?”
Frailty: This is defined in differing ways, but refers the combined effects of aging, disease, and factors such as nutritional status and functional ability that make some persons susceptible to adverse health outcomes. It is a prognostic concept, referring to people at risk of decline in health; it is the opposite of successful aging.
There are various ways of summarizing the impact of diseases on the health of a population. These are used in policy discussions: which condition is the most important? Which should receive more funding or research attention? A core challenge lies in finding a metric that fairly compares across fatal conditions and those (like Alzheimer's) that disable without killing.
Potential Years of Life Lost: Deaths occurring early in life are considered a more serious loss than later deaths, so in comparing the impact of diseases it may be better to consider not only total numbers of deaths, but also the age at which they occur. People who die prematurely are said to have lost years of potential life. 'Premature' can be defined in terms of the average life expectancy for a person of that sex, or an arbitrary value (such as 75 years) can be used for everyone.
These values could be summed over a population to indicate the impact (in terms of potential years of life lost) due to a particular disease in the population; this can be used in setting priorities among health issues in a society.
A Discussion Point: When prioritizing issues by PYLL, deaths that occur at younger ages (doing wheelies on your 1100 cc. Kawasaki) receive more weight than deaths that occur late in life (geriatric patients with pneumonia). This reflects a social judgment that the death of a young person is more significant than the death of an older person. Is the best way? Are there disadvantages? Is this ageism?
Interventions that prolong life may be evaluated by counting the additional years of life they confer. But this says nothing about the quality of those extra years: an intervention such as dialysis could extend a life but leave the patient in a disabled state, so each additional life-year gained is not really equivalent to a year of perfect health. This introduces the concepts of disability-adjusted life years (DALYs), and of quality-adjusted life years (QALYs). Both indicators combine morbidity and mortality outcomes.
Disability-Adjusted Life Years (DALYs): A measure of disease burden that is expressed as the sum of years lost to ill-health, disability or early death; one DALY is equivalent to the loss of a healthy life year.
(source: By DALY_disability_affected_life_year_infographic.png: Planemad derivative work: Radio89 [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons)
For example, a man with a disabling disease that lasts 5 years might be judged to have lost the equivalent of 2 years of healthy life because of this disability. If he contracts this condition at 69 and dies at age 74, he has lost 6 years of normal life expectancy (80 - 74), but in addition he has lost the equivalent of 2 further years due to the years of disability, to give a DALY of 8 years of healthy life lost due to this condition.
Quality-Adjusted Life Years (QALYs): A population health indicator that combines the quantity and quality of life. It is typically used to indicate the output of a new therapy on a whole-population basis.
The QALY extends the idea of life expectancy by incorporating an indicator of the quality of life among survivors. This helps to address the question of whether extending life expectancy (e.g., by life-saving therapies) may also increase the number of sick and disabled people in society. So, rather than count every year of life lived in a population as though they were equivalent, this statistic adjusts years lived in a state of disability or incapacity downwards: they are counted as being worth less than a full year of healthy life.
QALYs are calculated as the average number of additional years of life gained from an intervention, multiplied by a utility judgment of the quality of life in each of those years.
For example, a person might be placed on hypertension therapy for 30 years, which prolongs his life by 10 years at a slightly reduced quality level of 0.9. In addition, the need for continued drug therapy reduces his quality of life by 0.03. Hence, the QALYs gained would be 10 x 0.9 - 30 x 0.03 = 8.1 years. The valuations of quality may be collected from surveys; a subjective weight is given to indicate the quality or utility of a year of life with that disability.
Prevalence and Types of Disability in Canada
Most of our information on disability comes from surveys, since hospital statistics would only include severe and acute conditions that required hospital treatment. To record the prevalence of long-term disabling conditions, Statistics Canada has led many surveys of disability.
The information below comes from the 2012 Canadian Survey on Disability.
Total – aged 15+
15 to 64
15 to 24
25 to 44
45 to 64
65 and over
65 to 74
75 and over
Among people aged 65 and above, about one third reported some form of disability. The commonest forms of disability in seniors were pain (22.1%), mobility (20.5%) and lack of flexibility (19.3%). The prevalence of hearing disabilities among seniors was 10.4%.
Prevalence of disability by type, Canada, 2012, all ages
A Discussion Point: The conventional medical focus on disability takes a somewhat negative approach to health, perhaps because many doctors aim to cure diseases. The medical model of disability is grounded in the perspective that “disability resides in the individual and carries with it a degree of stigma or pathology.” In contrast, the social model places the locus of disability in environments that fail to appropriately accommodate and include people with disabilities.
A more holistic approach could consider both of these models and lead you to discuss with your patients about their personal wants, needs and health goals. A patient with disabilities may have priorities that differ from your own, and differ from those expected under a conventional medical model.
This refers to attitudes in society that devalue and limit the potential of persons with disabilities.
“Ableism sees persons with disabilities as being less worthy of respect and consideration, less able to contribute and participate, or of less inherent value than others. Ableism may be conscious or unconscious, and may be embedded in institutions, systems or the broader culture of a society. It can limit the opportunities of persons with disabilities and reduce their inclusion in the life of their communities.” - Ontario Human Rights Commission
Example: In one case, a female bartender developed an anxiety disorder and began to experience panic attacks after she was assaulted by two customers. Her employer accommodated her by allowing her to be absent when she was too ill to work. Then the complainant got a new manager who became impatient with her absences. A tribunal found that the manager discriminated against her when he reduced her shifts and made comments about her medical condition in front of others, including saying that she was “messed up” in her head, “needed drugs” and looked “pretty unstable.” (OHRC)
Our reactions to people with disabilities or handicaps reflect our attitudes, which are influenced by our culture, education and so forth. These are social facts as well as individual choices.
A 2009 paper by the Institute for Research and Development on Inclusion and Society found that the prevailing Canadian attitude of disability is one of “ambivalence, with an odd mixture of positive and negative attitudes, beliefs, perceptions, experiences and behaviours”. Many Canadians were unaware of the needs, experiences, contributions and activities of people with disabilities. This ambivalence and ignorance leads to a lack of public support for disability-rights motions. Nonetheless “Most Canadians hold a positive image of their own views towards and experiences with people with disabilities and believe that, over the last decade, progress has occurred in the inclusion of people with disabilities in community life (…). The resulting public opinion environment is one of pride and prejudice.”
Literature Review: Journalism and Disability from a Canadian Perspective (Canadian Journal of Disability)
Pride and Prejudice: The Ambivalence of Canadian Attitudes towards Disability and Inclusion (Iris Institute)
Challenge your Perspective
So, how does society approach disability? The definition of handicap refers both to the person and to the environment in which she or he lives, so increasingly we recognize the relevance of modifying society to fit the person with a disability. Consider the following wry commentary on some disability questions drawn from a British health survey:
Can you tell me what is wrong with you?
Can you tell me what is wrong with society?
What complaint causes your difficulty in holding, grasping, gripping or turning things?
What defects in the design of everyday equipment like jars, bottles and cans causes you difficulty in holding, gripping or turning them?
Are your difficulties in understanding people mainly due to a hearing problem?
Are your difficulties in understanding people mainly due to their inabilities to communicate with you?
Do you have a scar, blemish or deformity that limits your daily activities?
Do other people's reactions to any scar, blemish or deformity you may have, limit your daily activities?
Have you attended a special school because of a long-term health problem or disability?
Have you attended a special school because of your education authority's policy of sending people with your health problem or disability to such places?
Does your health problem or disability mean that you need to live with relatives or someone else who can help look after you?
Are community services so poor that you need to rely on relatives or someone else to provide you with the right level of personal assistance?
How difficult is it for you to get about your immediate neighbourhood on your own?
What are the environmental constraints which make it difficult for you to get about in your immediate neighbourhood?
Does your health problem or disability make it difficult for you to travel by bus?
Do poorly-designed buses make it difficult for someone with your health problem or disability to use them?
Does your health problem or disability affect your work in any way?
Do you have problems at work because of the physical environment or the attitudes of others?
The following language may help you understand the experiences of patients and colleagues with disabilities:
Able-bodied: used to refer to someone who is healthy and has no illness, injury, or condition that makes it difficult for them to do the things that other people do (Cambridge Dictionary)
Invisible Illness or Invisible Disability: disabilities that are not immediately apparent. May include visual or auditory disabilities, chronic pain, chronic fatigue, cognitive variations, etc. An invisible disability can be difficult for others to recognize or acknowledge. They may challenge the person with a disability or make assumptions, such as that the person is “lazy”.
Inspiration Porn: calling people with disabilities inspirational because of their disability. Alternatively, “Inspiration porn is an image of a person with a disability, often a kid, doing something completely ordinary - like playing, or talking, or running, or drawing a picture, or hitting a tennis ball - carrying a caption like "your excuse is invalid" or "before you quit, try" – Stella Young, disability rights activist and coiner of the term “inspiration porn” (link to original article and more extensive discussion)
Oliver Sacks noted that those who lose their hearing after they have learned to speak are in a better position than others who are prelingually deaf. This was echoed by David Wright, who became deaf around age 7:
“My becoming deaf when I did – if deafness had to be my destiny – was remarkably lucky. By the age of seven a child will have grasped the essentials of language, as I had. Having learned naturally how to speak was another advantage – pronunciation, syntax, inflexion, idiom, all had come by ear. I had the basis of a vocabulary which could easily be extended by reading. All of these would have been denied me had I been born deaf or lost my hearing earlier than I did." (David Wright, Deafness).
It is very hard for a hearing person to comprehend how a prelingually deaf person can acquire a vehicle for communicating abstract thought.
The establishment of
population-based infant hearing screening programs has helped to raise the
rate of detecting early deafness. Screening is universal in several European countries, in
more than 40 US states but in only 2 Canadian provinces.
Data from screening programs suggests that between 1 and 4 per thousand newborns have permanent hearing loss
(Fortnum HM et al. Br Med J 2001;8 (323): 536-540. Mehl AL. Pediatrics 2002;109:E7).
The most common predictors include a family history of hearing loss and craniofacial anomalies; deafness is more common among infants admitted to neonatal intensive care. However, about 50% of cases have none of these factors.
In the absence of neonatal screening, detection of hearing impairment occurs later. One study calculated a mean age of 2.8 years for detecting hearing loss in the absence of a screening program (Durieux-Smith A. J Speech-Lang Pathol 2000;2:59-67). Delayed recognition is associated with delayed development of speech and language, and perhaps reduced social and emotional function (Mohr E et al. Int J Technology Assessment in Health Care 2000;16:1120-35.) In the US, Mohr et al. found that 42% of people with severe hearing loss did not graduate from high school (versus 19% of the general population), and 42% were unemployed (versus 18% in the general population). We don't have figures for Canada.
American Sign Language (ASL), is the language used by the Deaf in Canada and USA. It is a fundamental language in Deaf culture and forms a symbol of social identity, a medium of social interaction, and a store of cultural knowledge. In Quebec, Langues Signées des Québécois (LSQ) is used by Deaf Francophones. ASL has its own distinct grammar and syntax. It has its own structure composed of four main elements; handshapes, their location, orientation and movements.
- Whenever possible, face the person. Do not try to talk to them with your back turned!
- Reduce background noise (turn off t.v., radio)
- Get the person’s attention before your speak (wave your hand, or touch them on the shoulder)
- Face the light to make it easier for them to lip-read. Make sure light is not shining in their eyes
- Your speech will be more readily understood if you are not eating, chewing gum, etc
- Maintain eye contact when speaking. Use body language, facial expressions: be animated!
- Keep your hands away from your face when speaking
- If the person does not understand something, rephrase rather than than merely repeating the original words more loudly
- People who are hard of hearing hear and understand less well when they are tired or sick
- A woman's voice may be harder for a person with hearing difficulties to understand; maybe try lowering the pitch of your voice
- Speak slowly and clearly: do not shout
- If the person wears a hearing aid, make sure it's turned on and the batteries are good!
- Speak to the side on which they hear best
- In a group setting, place the person where they can see everyone (e.g., at the head of the table)
- Try to announce when you are going to change the topic of conversation; this may help them avoid a faux pas
- Be aware that letters such as b, c, d, e, t, and v sound alike, as do some numbers, such as 16 and 60. It may be necessary to clarify by saying "M as in Mary", etc.
- Keep a note pad handy
- Be patient.
(Adapted from Gerinet, the Internet Geriatric Health)
Updated August 3, 2017