Assessing Disability – World Health Organization Disability Assessment Schedule II

(WHODAS II)

Mr Vaikunthan Rajaratnam MBBS(Mal),AM(Mal),FRCS(Ed),FRCS(Glasg),FICS(USA),MBA(USA),

Dip Hand Surgery(Eur),PG CertMedEd(Dundee),FHEA(UK),AFFST(Ed),FAcadMEd(UK).

Senior Consultant Hand SurgeonAlexandra Health, SINGAPORE

Disability and Damage

Injury/Illness Treatment Intervention Outcome

43 year-old female, right-handed, cook

Traumatic amputation of right thumb and index finger

Unreplantable thumb

Underwent right thumb reconstruction with right big toe osteoplastic wrap-around flap 1 week post-injury, after counseling and consenting

Toe wrap based on dorsalis pedis

Defining•

Impairment: any loss or abnormality of psychological, physiological or anatomical structure or function.

•Disability: 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.

•Handicap: a disadvantage for a given individual that limits or prevents the fulfilment of a role that is normal

•As traditionally used, impairment refers to a problem with a structure or organ of the body; disability is a functional limitation with regard to a particular activity; and handicap refers to a disadvantage in filling a role in life relative to a peer group.

World Health Organization (1980) in The International Classification of Impairments, Disabilities, and Handicaps:

International Classification of Functioning, Disability and Health (ICF)

• classified from body, individual and societal perspectives

• measuring health and disability at both individual and population levels

• shifting the focus from cause to impact• the social aspects of disability

– http://apps.who.int/classifications/icfbrowser/

Psychometrics

construction and validation of measurement instruments such as questionnaires, tests, and

personality assessments

Katies , tahils and pikul

Classical test theory• reliability and validity.

– Pearson correlation coefficient, and is often called test-retest reliability.

– index of reliability is Cronbach's α

• concurrent validity; predictive validity, construct validity, Content validity

WHODAS II

• ISBN 978 92 4 154759 8 • (NLM classification: W 15)• © World Health Organization 2010• http://p.ideaday.de/104.2/icf/en/index.html

WHODAS II

• generic assessment instrument• standardized method for measuring health

and disability• developed from a comprehensive set of

International Classification of Functioning, Disability and Health (ICF)

• Cross cultural applicability, utility, reliability and validity

Why is disability assessment important?

• “there are no diseases, but patients”

• There are no disabilities but people with problems that affect their lives

Why develop a method to assess disability?

• “a decrement in each functioning domain”– Body, person and society

• International Classification of Functioning, Disability and Health (ICF) – impractical for daily use

• WHODAS 2.0 – practical, reliable and valid

Why learn and use a disability measure?

• patient’s needs• level of care• outcome of the condition• length of hospitalization• receipt of disability benefits• work performance• social integration

Disability assessment

• identifying needs• matching

treatments and interventions

• measuring outcomes and effectiveness

• setting priorities• allocating resources.

Why use WHODAS 2.0?

• sound theoretical underpinnings• good psychometric properties• numerous applications• direct link to the ICF• Cross-cultural comparability• Ease of use and availability

WHODAS 2.0practical, generic assessment instrument measuring health and disability

• 1: Cognition – understanding and communicating• 2: Mobility – moving and getting around• 3: Self-care – attending to one’s hygiene, dressing, eating and staying alone• 4: Getting along – interacting with other people• 5: Life activities – domestic responsibilities, leisure, work and school• 6: Participation – joining in community activities, participating in society.

WHODA II contd

• common metric• generic measure• possible to design and monitor interventions• etiologically neutral• focus directly on functioning and disability• full version has 36 and the short version 12

questions

Bio psychosocial model of ICF

• disability is multidimensional• interaction between attributes of an individual

and features of the person’s physical, social and attitudinal environment

WHODAS and WHOQOL

• WHODAS 2.0 measures functioning (i.e. an objective performance in a given life domain), while WHOQOL measures subjective well-being (i.e. a feeling of satisfaction about one’s performance in a given life domain).

• Does vs Feel

36-item version

• interviewer-administered, self-administered and proxy-administered

• most detailed• 20 minutes.

12-item version

• brief assessments of overall functioning• interviewer-administered, self administered

and proxy-administered.• explains 81% of the variance of the 36-item

version• five minutes.

12+24-item version

• hybrid of the 12-item and 36-item versions• Based on positive responses to the initial 12

items, respondents may be given up to 24 additional questions

• administered by interview or computer-adaptive testing (CAT).

• 20 minutes.

Psychometric properties

• Test–retest reliability and internal consistency - Cronbach’s alpha levels 0.98

• Most questions fitted in their assigned domains, confirming the unidimensionality of domains

• summary change scores were unaffected by sociodemographic factors

• Face , construct and concurrent validity

Practical aspects of administering and scoring

• Privacy• • frame 1 – degree of difficulty• • frame 2 – due to health conditions• • frame 3 – in the past 30 days• • frame 4 – averaging good and bad days• • frame 5 – as the respondent usually does the

activity• • frame 6 – items not experienced in the past 30

days are not rated.

Frame of reference 1 – degree of difficulty

• • increased effort• • discomfort or pain• • slowness• • changes in the way the person does the

activity.

Frame of reference 2 – due to health conditions

• diseases, illnesses or other health problems• • injuries• • mental or emotional problems• • problems with alcohol• • problems with drugs.

Scoring

• “none” (1), • “mild” (2) • “moderate” (3), • “severe”(4) and • “extreme” (5)

Simple vs complex scoring

• Questions A1–A5: Demographic and background information1: Cognition – understanding and communicating• 2: Mobility – moving and getting around• 3: Self-care – attending to one’s hygiene, dressing, eating and staying alone• 4: Getting along – interacting with other people• 5: Life activities – domestic responsibilities, leisure, work and school• 6: Participation – joining in community activities, participating in society.• Questions F1–F5: Face sheet

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