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Assessing disability – world health organization disability assessment WHO DAS 2.0

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Universal generic assessment of disability using the WHO Disability Assessment Schedule 2.0

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Assessing disability – world health organization disability assessment WHO DAS 2.0

  1. 1. 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),Dip MedEd(Dundee),FHEA(UK),FFST(Ed),FAcadMEd(UK). Senior Consultant Hand Surgeon Alexandra Health, SINGAPORE
  2. 2. Disability and Damage Injury/Illness Treatment Intervention Outcome
  3. 3.  43 year-old female, right-handed, cook Traumatic amputation of right thumb and index finger 
  4. 4. Unreplantable thumb
  5. 5. Underwent right thumb reconstruction with right big toe osteoplastic wraparound flap 1 week post-injury, after counseling and consenting
  6. 6. Toe wrap based on dorsalis pedis
  7. 7. • 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:
  8. 8. 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/
  9. 9. Psychometrics construction and validation of measurement instruments such as questionnaires, tests, and personality assessments
  10. 10. 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
  11. 11. 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
  12. 12. 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
  13. 13. Why is disability assessment important? • “there are no diseases, but patients” • There are no disabilities but people with problems that affect their lives
  14. 14. 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
  15. 15. 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
  16. 16. Disability assessment • identifying needs • matching treatments and interventions • measuring outcomes and effectiveness • setting priorities • allocating resources.
  17. 17. 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
  18. 18. WHODAS 2.0 practical, 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.
  19. 19. 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
  20. 20. 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
  21. 21. 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
  22. 22. 36-item version • interviewer-administered, self-administered and proxy-administered • most detailed • 20 minutes.
  23. 23. 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.
  24. 24. 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 computeradaptive testing (CAT). • 20 minutes.
  25. 25. 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
  26. 26. 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.
  27. 27. Frame of reference 1 – degree of difficulty • • • • • increased effort • discomfort or pain • slowness • changes in the way the person does the activity.
  28. 28. 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.
  29. 29. Scoring • • • • • “none” (1), “mild” (2) “moderate” (3), “severe”(4) and “extreme” (5) Simple vs complex scoring
  30. 30. • Questions A1–A5: Demographic and background information 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. • Questions F1–F5: Face sheet
  31. 31. THANK YOU

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