Disability and Handicap Examples of Conceptual Foundations for Measurement Scales
Three Perspectives: Disease, Sickness & Illness Sickness (Social & cultural conceptions of the condition: cultural beliefs and reactions such as fear or stigma. These affect how the patient reacts, and also what is considered a disorder suitable for medical treatment) Disease (Underlying pathology; biologically defined: the practitioner’s perspective. The illness seen in terms of a biological theory of disorder) Illness (The person’s subjective experience of their symptoms. What the patient brings to the doctor)
WHO Classifications International Classification of Diseases (ICD) Etiological framework Diagnosis of health condition Disease process, signs & symptoms International Classification of Impairments, Disabilities & Handicaps (ICIDH) How people live; body functions Framework to describe activities & participation Covers non fatal outcomes
Conceptions of Disability “a disability is any restriction or lack of ability (resulting from an impairment) to perform an activity in the manner or within the range considered normal for a human being” (WHO International Classification of Impairments, Disabilities, and Handicaps, 1980.)
ICIDH* - 1 Impairment DisabilityHandicap (N.b. dotted arrows indicate that one stage may, but need not, influence the next) Internal, body Societal * International Classification of Impairment, Disability & Handicap Applied
Issues in the Definition Defining disability in terms of activity limitations is neat, but what activities? What level of limitation should be used? Same expectations for everyone, or relative to age, sex, etc.? Threshold: does not perform an activity, versus cannot perform it? Maybe doesn’t, but could?
ICIDH - 2 Appeared March, 2001 Conceptual changes: From consequences of disease (1980) to components of health (2000) Uses more positive language (‘activity’ & ‘participation’ instead of ‘disability’ & ‘handicap’) Broadens concept of disability More on environmental factors in which the person lives
ICIDH - 2 Body Functions & structures ActivitiesParticipation BODY Structure & Function PERSON Activities SOCIETY Participation impairmentlimitationrestriction Health Condition (disorder / disease)
Body Functions Mental functions Sensory Voice & speech CVD, hematological, etc. Digestive, metabolic & endocrine Genitourinary Neuro-musculoskeletal Skin
Activities & Participation Learning Communication Movement Self-care Domestic activities Interpersonal Major life activities Community Exchanging information Communicating Mobility Personal maintenance Home life Social relationships Work & employment Social & civic life
High positive affect Low positive affect High negative affect Low negative affect Disengagement Pleasantness Strong engagement Unpleasantness content, happy, satisfied active, elated, excited aroused, astonished, concerned relaxed, calm, placid distressed, fearful, hostile sad, lonely, withdrawn sluggish, dull, drowsy inactive, still, quiet A ‘Circumplex’ Model
Health-Related Quality of Life QoL is deliberately subjective & value-specific Invented in the USA How universally applicable is it? Definition will surely vary across cultures (naïve early enthusiasm for QoL as final outcome) Handicap reflects impairment + environment, so measures may perform differently in different environments
Quality of life is… “Having the important people in your life see your strengths and talents” “A good night’s sleep” “Validation of worth and affirmation of experience” “Having control of your own life” “Taking control of your health condition” “Life free from stigma” “Having a ‘real’ job” “Having a purpose” “Being free to come and go” Quality of Life (from a consumer’s perspective) Carne, B. A consumer perspective. Can J Community Mental Health 1998, Suppl 3: 21.
The Deceptive Simplicity of HRQOL… Health-Related Quality of Life Definition? What model? (Caused by Associated with? or ?) Or Quantity? (How would we we measure quality?) Of life or Living?
Disease-Specific Dysfunction Health-Related Quality of Life Overall Quality of Life Mapping Physical Measures onto Quality of Life Source: SH Kaplan et al. Medical Care, 2000 cover part of (the clinician’s concern) Clinical / Physical Markers (the patient’s concern)