THE ULTIMATE GOAL of rehabilitation in people with

Transcription

1 210 Psychometric Properties of the Impact on Participation and Autonomy Questionnaire Mieke Cardol, OT, Rob J. de Haan, RN, PhD, Bareld A. de Jong, MD, PhD, Geertrudis A.M. van den Bos, PhD, Imelda J.M. de Groot, MD, PhD ABSTRACT. Cardol M, de Haan RJ, de Jong BA, van den Bos GAM, de Groot IJM. Psychometric properties of the impact on participation and autonomy questionnaire. Arch Phys Med Rehabil 2001;82: Objective: To examine the homogeneity, test-retest reliability, construct validity, and concurrent validity of the Impact on Participation and Autonomy Questionnaire (IPAQ). Design: Cross-sectional study with a test-retest subsample. Patients: One hundred twenty-six persons from 5 diagnostic groups recruited from the outpatients clinics of 2 rehabilitation centers and the rehabilitation department of an academic hospital. Interventions: The IPAQ and 3 other self-administered questionnaires (Sickness Impact Profile [68-item version], London Handicap Scale [LHS], Medical Outcome Study Short- Form Health Survey). The IPAQ was completed twice by 75 respondents within approximately 2 weeks. Results: The IPAQ addresses autonomy and participation in 5 domains: autonomy indoors, family role, autonomy outdoors, social relations, and work and educational opportunities. Cronbach s alpha for the several domains ranged between.81 and.91, indicating good homogeneity. On item level, weighted kappas ranged between.56 and.90. On domain level, the test-retest reliability of the IPAQ was good: intraclass correlation coefficients ranged between.83 and.91. Convergent validity was largely supported by the correlations between 4 domains of the LHS and the IPAQ. Discriminant validity was best demonstrated by low correlations between the IPAQ and 2 domains of the LHS representing theoretically different constructs. Conclusion: The IPAQ is a reliable and valid instrument for assessing autonomy and participation in chronic disorders. Its responsiveness requires further study. Key Words: Rehabilitation; Netherlands; Disability evaluation; Assessment; Patient outcome by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation From the Departments of Rehabilitation (Cardol, de Jong, de Groot), Clinical Epidemiology and Biostatistics (de Haan), and Social Medicine (van den Bos), Academic Medical Center, University of Amsterdam, Amsterdam; and the National Institute of Public Health and Environment, Dept for Health Services Research (van den Bos), Bilthoven, The Netherlands. Accepted in revised form May 15, Supported in part by the Albert Heijn Trust Fund. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated. Reprint requests to Mieke Cardol, Dept of Rehabilitation, Academic Medical Center, PO Box 22660, 1100 DD Amsterdam, The Netherlands, m.cardol@amc.uva.nl /01/ $35.00/0 doi: /apmr THE ULTIMATE GOAL of rehabilitation in people with chronic health problems is to optimize their participation in society, thereby preventing or reducing perceived handicaps. In the International Classification of Impairments, Disabilities, and Handicaps (ICIDH), 1 handicap reflects the outcome of a complex relationship between the person with impairment or disability and the physical, social, and cultural environment. The ICIDH and its concept of handicap have triggered much discussion. Currently, the ICIDH is being revised. In the proposed revision (ICIDH-2), 2 the name of the handicap domain has been changed to participation to improve clearness, understanding, and use of the concept. This new domain of participation refers more to autonomy and the personal fulfillment of roles rather than a normal role fulfillment, as stated in the current ICIDH. Because the environment is important in the handicapping process, a list with environmental factors has been added to the ICIDH-2. However, the definition of participation still focuses on an individual s ability to participate, rather than on the context. 3 It is argued that it is useless to classify social situations, because their relevance differs between individuals and the amount and nature of environmental factors is infinite. 3 Some instruments have been developed to assess a person s handicap or restriction in participation. Generally, these instruments do not reflect an individual s perception and needs, but are normative and focus on general abilities, tasks, and roles. 4 For this reason, we developed the Impact on Participation and Autonomy Questionnaire (IPAQ). Rather than focusing on ability or capacity, the IPAQ focuses on autonomy and participation of people with chronic disorders. The scale was developed for use as a profile for disease severity assessment, needs assessment, and outcome assessment (evaluation). It is selfadministered and presently consists of 5 domains: social relations, autonomy in self care, mobility and leisure, family role, and work and educational opportunities. One item was added concerning overall perceived participation (living the life one wants). The IPAQ s homogeneity, content validity, and construct validity (by factor analysis) have been previously reported. 5 Strictly speaking, one cannot establish reliability and validity of an instrument at a single point in time; rather one can support some application of that instrument in a specific sample. 6 Because the IPAQ is intended to be a generic questionnaire, the present study sought to repeat the factor analysis and to test the homogeneity of the IPAQ in a different sample. We also report here on the test-retest reliability and the convergent and discriminant validity of the IPAQ. METHODS Study Population The IPAQ was tested in 5 diagnostic groups of regular consumers of rehabilitation treatment: persons with respectively, neuromuscular disease, stroke, spinal cord injury (SCI), rheumatoid arthritis, or fibromyalgia. Excluded were persons younger than 18 years or older than 75 years, and people with difficulty in comprehending the Dutch language.

2 IMPACT ON PARTICIPATION AND AUTONOMYQUESTIONNAIRE, Cardol 211 We included 150 consecutive individuals, 30 persons in each group. The participants were recruited from the outpatient clinics of a general rehabilitation center (stroke and SCI, n 60); from a rehabilitation center that specializes in rheumatologic conditions (rheumatoid arthritis and fibromyalgia, n 60); and from the outpatient rehabilitation department of an academic hospital in the Netherlands (neuromuscular disease, n 30). Persons who agreed to participate were sent the IPAQ and 2 validated and widely used questionnaires in rehabilitation medicine: the Sickness Impact Profile 68-item version (SIP68) 7,8 and the Medical Outcome Study Short-Form Health Survey (SF-36). 9,10 Another validated questionnaire, the London Handicap Scale (LHS), was also sent because of its concept of handicap. Completed questionnaires were returned to the researcher (MC) by mail. If questionnaires were not returned in time, reminders were sent. The IPAQ was completed twice in an interval of approximately 2 weeks by 75 respondents (randomly selected). Instruments The IPAQ assesses 2 aspects of participation: (1) perceived participation for each item (n 31), and (2) the perceived problem for each subdomain (n 8). The subdomains of the IPAQ cover all topics, also the topics that are combined in one domain. This second rating should reflect the personal burden of a perceived restriction in participation in every day life, and is important in relation to the goals that are set in the rehabilitation treatment program. Perceived participation is graded on a 5-point rating scale with discrete responses, ranging from 1 (very good) to 5 (very poor). The perceived problem score is graded on a 3-point rating scale ranging from 0 (no problem) to 2 (severe problem). For each domain the participation score and problem-experience score are calculated by summing the item scores. Higher scores denote more restrictions in participation and/or a higher problem experience on the specific domain. The SIP68, a short version of the SIP136, measures healthrelated functional status. 7,8 Its 68 items are divided into 3 broad domains. The physical domain includes the subscales somatic autonomy (eg, getting dressed, walking) and mobility control (behavior related to walking and arm function). The psychic domain consists of the subscales psychic autonomy and communication and emotional stability (the effect of health status on emotional behavior). The last domain addresses social and mobility aspects and consists of the subscales social behavior and mobility range (instrumental daily activities). The response options of the SIP68 are dichotomous. The positive item scores are added for each domain, with a higher score indicating more limitations in functional health status. The SF-36 is a questionnaire that rates general health perception; it consists of 8 multi-item subscales in 2 dimensions, physical and mental. The physical dimension consists of 4 subscales: physical functioning, role limitations caused by physical problems, bodily pain, and general health perception. The mental dimension contains these subscales: role limitations caused by emotional problems, social functioning, mental wellbeing, and vitality. 9,10 The item health change was added to the SF-36, but is not included in the 8 subscales. For each dimension, item scores are coded, summed, and transformed on a scale from 0 (worst health) to 100 (best health). The LHS is based on the ICIDH and generates a profile of handicaps on 6 dimensions and 1 overall handicap score. The 6 rather broadly defined dimensions encompass mobility (getting around), physical independence (getting dressed, shopping, looking after money, housework), occupation (work, gardening, traveling, reading, going out with friends), social integration (getting on with people), orientation (awareness of surroundings), and economic self-sufficiency (affording the things one needs). Each dimension contains 1 item with a weighted score. A lower score indicates greater handicap Because a Dutch version of the LHS is not available, we translated it into Dutch, using a forward-backward procedure with an native English speaker. Reliability of the IPAQ In this study, reliability concerns homogeneity and test-retest reliability of the IPAQ. Homogeneity refers to the statistical coherence of the scale items, and was expressed in Cronbach s alpha correlation coefficients. This coefficient is based on the (weighted) average correlation of items within an index. 14 Homogeneity is considered good if alpha ranges between.70 and Test-retest reliability refers to the score agreement between 2 measurements. On item level, the score agreement was quantified with Cohen s weighted kappa b Weighted kappa represents the proportion of agreement corrected for chance agreement in ordinal scales. Maximum weights are given to minimal disagreement. In general, with a value of kappa less than.40, the agreement is considered poor to fair, indicates moderate agreement, good agreement, and when kappa exceeds.80 the agreement is very good. 20 On domain level we used the intraclass correlation coefficient (ICC) for continuous variables. We calculated ICCs according to the 1-way random effects model, described by Shrout and Fleiss a The ICC can be regarded as the parametric variant of the kappa statistic, and can be interpreted accordingly. The procedure was based on 1-way analysis of variance, with the ratio of the variability between subjects to the total variability interpreted as a correlation coefficient. The differences between mean scores of the 2 measurements with their 95% confidence interval were also calculated. Construct Validity of the IPAQ Construct validity refers to the proposed underlying factors or theoretical concepts of a scale. 6 The theoretical construct of the IPAQ was analyzed with factor analysis, which explores the interrelationships among variables to discover factors measuring the same hypothetical construct. 25 The items addressing problem experience have not been analyzed, because they were considered to belong to a different construct. We strived for a factor structure somewhat similar to the structure yielded by our former factor analysis. 5 Convergent and Discriminant Validity of the IPAQ Convergent validity refers to the assumption that different methods of measuring the same theoretical concept yield similar results, whereas discriminant validity refers to the ability to differentiate the concept being measured from other constructs. 6 To support convergent validity, the scores of the IPAQ were associated (with Pearson s product moment correlation coefficient) to the domains of the LHS, SIP68, and SF-36 that measure related constructs. It was hypothesized, for instance, that (1) social relations and autonomy outdoors (IPAQ) should correlate with social integration (LHS), and that (2) autonomy outdoors (IPAQ) and the physical dimension of the SF-36 should show higher correlations than correlations between domains measuring different concepts. Similarly, to support discriminant validity, the correlations between different

3 212 IMPACT ON PARTICIPATION AND AUTONOMYQUESTIONNAIRE, Cardol constructs were analyzed. For example, it was assumed that (1) social relations (IPAQ) and economic self-sufficiency (LHS) and (2) autonomy indoors (IPAQ) and the social dimension of the SIP68 should show lower correlations than correlations between domains measuring similar constructs. RESULTS Study Population A total of 257 questionnaires were mailed; 126 questionnaires were returned (response rate, 49%). Response rates of the various diagnostic groups differed: 86% response for neuromuscular disease, 47% for SCI, 45% for stroke, 42% for rheumatoid arthritis, and 37% for fibromyalgia. Mean age standard deviation of the study population was years; 78 of the respondents were women. Median duration of disease ranged between 2 and 12 years, with the smallest range in the group with stroke. Thirty-five percent of the respondents lived alone, 24% were employed, and 11% had a cultural background other than Dutch. Characteristics of the study population are presented in table 1. Construct Validity and Homogeneity Oblique rotations (assuming dependent factors) and varimax rotations (assuming independent factors) produced the same factor solutions. In addition, the differences in loading between the pattern and structure matrix were not substantial, indicating that the factors are essentially orthogonal. 26 For this reason, we present only the results of the varimax rotation. Varimax rotation with a 4-factor solution showed that the factors could best be interpreted according to the following domains of participation: autonomy indoors, family role, autonomy outdoors, and social relations (table 2). With this factor solution, 67% of the total variance could be explained. Most variance was explained by the factor addressing autonomy indoors (43%). The domain addressing work and educational opportunities (n 6 items) was left out of the factor analysis, because this combination of items was only applicable to 19 persons. Table 1: Characteristics of the Study Population (n 126) Mean age (yr) (SD) 52.6 (13.4) Diagnosis (n) (%) Median duration of disease, range Neuromuscular disease 31 (25) 12yr (1 54) Rheumatoid arthritis 25 (20) 26yr (4 47) Fibromyalgia 22 (17) 2yr (1 10) Stroke 27 (21) 2yr (1 6) Spinal cord injury 21 (17) 4yr (1 27) Median disease duration for total group, range 4yr (1 54) Gender Men 48 (38) Women 78 (62) Living alone 44 (35) Professional help (care, therapy) 60 (48) Educational Level Primary school 15 (12) Secondary school 76 (60) High school 27 (21) University 8 (6) Employed 30 (24) No Dutch cultural background 14 (11) The homogeneity of the domains was good: Cronbach s alphas were.91 (autonomy indoors),.90 (family role),.81 (autonomy outdoors),.86 (social relations), and.91 (work and educational opportunities) Test-Retest Reliability of the IPAQ Seventy-five questionnaires were sent and 72 were returned (response rate, 96%). Mean duration between the 2 measurements was days (range, 9 27d). Weighted kappa ( w ) for the perceived participation score of separate items ranged between.56 and.90. The w for the problem-experience score ranged between.59 and.87 (table 3). In 3 items moderate agreement between the 2 measures was present: in 2 items addressing family role ( w.56,.59), and in the item addressing perceived problem in self-care ( w.59). With regard to test-retest reliability on domain level, no significant difference between the mean scores of the measurements was found, indicating good test-retest reliability. ICCs ranged from.83 (family role) to.91 (autonomy outdoors) (table 4). Convergent and Discriminant Validity Convergent validity was best supported by the correlations between the IPAQ and 4 domains of the LHS: mobility, physical independence, occupation, and social integration (table 5). As expected, the correlations between social relations and autonomy outdoors (IPAQ) (r.51) and social integration (LHS) (r.57) were substantial. Correlations between autonomy indoors, autonomy outdoors, and family role (IPAQ) and mobility, occupation, and physical independence (LHS) were also in agreement with our hypotheses (range, r.42 to.57), supporting convergent validity. The correlation between the physical dimension of the SIP68 and autonomy indoors was lower than expected (r.29). In accord with our hypothesis, correlations between autonomy indoors, family role, and autonomy outdoors (IPAQ) and the physical domain of the SF-36 were substantial (range, r.43 to.51). Discriminant validity was best supported between the IPAQ and 2 domains of the LHS, orientation, and economic selfsufficiency (table 5). As hypothesized, correlations between all domains of the IPAQ and the domains economic self-sufficiency and orientation (LHS) were low (range, r.01 to.29), demonstrating discriminant validity. Discriminant validity between the IPAQ and the domains of the SIP and SF-36 could only be demonstrated by the low correlation between the domain social relations (IPAQ) and the physical domain of the SF-36 (r.26) and the physical domain of the SIP (r.16). DISCUSSION Many authors have emphasized that it is not the instrument that has to be validated, but its application for a certain purpose in a certain population. 6,27-30 Because the IPAQ is meant to be a generic questionnaire, its psychometric properties were evaluated in a heterogeneous study population. In our sample, the response rate for persons with fibromyalgia was especially low. Response rates tend to be lower among the sick and the elderly, and to quantify the impact of nonresponse one should test for selection bias. 31 Unfortunately, we were not able to study the reasons for nonresponse, and therefore cannot reach to conclusions as to whether they were related to the health status or sociodemographic characteristics of the nonrespondents, or whether the reasons were related to our study design or the content of the questionnaires.

4 IMPACT ON PARTICIPATION AND AUTONOMYQUESTIONNAIRE, Cardol 213 Table 2: Factor Analysis: Rotated* Loadings for 4-Factor Solution (n 126) Factor Autonomy Indoors Family Role Autonomy Outdoors Social Relations Explained variance 43% 11% 7% 6% Items of the IPA Taking a bath and dress the way one wants Taking a bath and dress when one wants Going to bed at the time one wants 0.78 Going to the bathroom when one needs to 0.69 Eating and drinking when one wants Getting around indoors where one wants Getting around indoors when one wants Contribution to housekeeping Light household activities the way one wants Major household activities the way one wants 0.81 Household activities when one wants 0.89 Repairs and upkeep of the home 0.80 Fulfilling one s role at home Spending income the way one wants Visiting friends when one wants Making day trips, taking vacation, etc 0.74 Frequency of social contacts Living the life as one likes Leisure time as one likes Communication with nearest Relationship with nearest 0.86 Respect from nearest 0.81 Contact with acquaintances Respect from acquaintances Intimate relationship * Rotation is a statistical procedure to facilitate the identification of the underlying dimensions. Loadings represent the correlation coefficients between factors and items. When r.30, loadings are not presented in order to improve clarity. Table 3: Test-Retest Reliability of the IPAQ: Range of Weighted Kappas ( w ) for Each Domain and for Items on Problem Experience Domains for Perceived Participation w range Respondents (n) Autonomy indoors (7) Family role (7) Autonomy outdoors (5) Social relations (6) Work and education (6) (work), 11 (education) Rating for Problem Experience* w range Respondents (n) Autonomy in self-care (1) Autonomy in mobility (1) Family role (1) Spending income (1) Leisure (1) Social relations (1) Work (1) Education (1) * Items for problem experience were based on the subdomains, as explained in the Methods section. Homogeneity and test-retest reliability of the IPAQ are good. With regard to test-retest reliability on item-level, moderate agreement was present in only 3 items: the problemexperience regarding autonomy in self-care, perceived participation concerning heavy household activities and repairs and upkeep of the home to one s satisfaction. The agreement on domain level, as measured with ICCs, was good. However, ICCs are known to be dependent on the range of measurements, ie, the more variability between the subjects, the greater the correlation and the better the agreement. 23 From a clinical view, factor analysis revealed an adequate structure. The 5 domains consist of different aspects and the measure can be used as a starting point or end point of rehabilitation interventions. The items addressing leisure, spending income, and intimate relationship can be considered psychometrically weak, because they load on, ie, are correlated with, more than 1 factor. Spending income belongs to the theoretical construct of participation (ICIDH-2), but as in our former analyses, it does not clearly fit into 1 domain. A probable reason for this is that spending income consists of a single item and factor analysis cannot make a domain out of 1 item. Furthermore, psychometrics differ from reality. For instance, leisure time can be spent indoors and outdoors; this may be the reason for the small difference in loading between 2 domains. In view of clinical considerations, we decided that the item addressing intimate relationship corresponds best with the items in factor 4 (social relations). We were unable to obtain the same structure as in our former analysis, in which mobility appeared to be a separate domain that also encompassed leisure. 5 Part of factor analysis is more or less subjective, such as the chosen rotation and factor solution, and the best factor solution chosen in view of statistical and clinical considerations. 6 Furthermore, the ratio of subjects to items in our study was 126:25, less than the 10:1 ratio recommended for

5 214 IMPACT ON PARTICIPATION AND AUTONOMYQUESTIONNAIRE, Cardol Table 4: Results for Test-Retest Reliability: Mean Scores, Differences Between the Mean Scores, and ICCs Domains Test 1 Retest Mean CI ICC CI IPAQ (range of score) Mean Score Mean Score Difference Mean Difference ICC Indoors (0 35) to Family role (0 35) to Outdoors (0 25) to Social relations (0 30) to Abbreviation: CI, confidence interval. stable factors. For this reason, we repeated post hoc a factor analysis with the samples of this study (n 126) together with the sample from our previous study (n 100), for total 226 respondents. Apart from the items addressing leisure time and spending income, we did find the same structure as presented in this article. For this reason, we propose that the domains as presented here, together with a domain named work and educational opportunities, form the scale structure of the IPAQ (see appendix). However, a definite statement can only be made when the domain work and educational opportunities has been tested in a sample with sufficient working and school-going individuals. The domains of the empirically based factor solution of the IPAQ can be found in the theoretically based structure of the dimension participation of the ICIDH-2, although the composition of the domains is different. For example, in the ICIDH-2, participation in mobility is a separate domain, whereas in the IPAQ the items addressing mobility are divided into 2 domains: autonomy indoors (mobility indoors) and autonomy outdoors (mobility outdoors). Convergent validity was supported by the correlations between the domains of the IPAQ and the 4 domains of the LHS measuring theoretically similar concepts. The correlations between the physical dimension of the SIP and the domains of the IPAQ were lower than expected. This may be because the SIP stresses behavior and independence, whereas the IPAQ stresses autonomy in personal life roles and how these roles are performed. Dependency does not necessarily exclude autonomy as Table 5: Convergent and Discriminant Validity: Pearson s Correlation Coefficients Between the IPAQ and Domains Measuring Similar* or Different Theoretical Constructs IPAQ Indoors Family Role Outdoors Social Relations LHS Mobility Physical Independence Occupation Social integration Orientation Economic self-sufficiency SIP68 Physical Social Psychic SF-36 Physical Mental * Expected similar constructs are presented in bold. Expected different constructs are presented in italics. Scoring Direction: IPAQ, Higher scores indicate more restrictions in participation; LHS, Higher scores indicate less restrictions in participation; SIP, Higher scores indicate more limitations in functional health status; SF-36, Higher scores indicate better health. long as the support is in accord with the individual s wishes. This may be the explanation for the higher correlations with the physical and mental dimension of the SF-36, in which items regarding limitations in role performance are included. Discriminant validity was best supported by the low correlations between the IPAQ and 2 dimensions of the LHS, orientation and economic self-sufficiency. We believe that orientation is more related to impairments than to handicaps. However, the r s between orientation (LHS) and social relations (IPAQ) were higher than expected. Obviously, one must be aware of one s surroundings to be able to communicate with the people of one s choice. All questionnaires used address part of the health status of the individual, although they focus on different aspects. For example, vitality and mental wellbeing (SF-36) and mobility control (SIP68) will correlate with social participation, although they do not belong to the same theoretical construct. Perhaps to support further discriminant validity between the IPAQ and other questionnaires, we should have considered a totally different theoretical concept, such as coping or satisfaction with health care. CONCLUSION Based on our findings, we conclude that the IPAQ is related to other health status questionnaires as described above, but differs from them because of its focus on autonomy and participation as perceived by the person. The IPAQ can be regarded as complementary to health status instruments and important for rehabilitation practice, because optimizing participation is the ultimate goal in the rehabilitation of the chronically ill. Furthermore, the IPAQ can be considered a reliable and valid questionnaire for the assessment of autonomy and participation in a heterogeneous population. However, its responsiveness (ie, sensitivity to change) requires further study. Acknowledgments. The authors thank the respondents who took part in the study and the rehabilitation centers Revalidatie Centrum Amsterdam and Jan van Breemen Instituut for their cooperation in recruiting participants for this study. We also thank Anita Beelen for general support, and Professor C.D. Ward for translating the IPAQ. References 1. World Health Organization. The International Classification of Impairments, Disabilities, and Handicaps. Geneva: WHO; World Health Organization. ICIDH-2: International Classification of Impairments, Activities, and Participation. A manual of dimensions of disablement and health. Beta-1 draft. Geneva: WHO; WHO Collaborating Centre for the ICIDH in the Netherlands. Newsletter 2. Bilthoven: RIVM [National Institute of Public Health and the Environment]; Cardol M, Brandsma JW, De Groot IJM, Van Den Bos GAM, De Haan RJ, de Jong BA. Handicap questionnaires: what do they assess? Disabil Rehabil 1999;21: Cardol M, De Haan RJ, Van Den Bos GAM, De Jong BA, De Groot IJM. The development of a handicap assessment question-

6 IMPACT ON PARTICIPATION AND AUTONOMYQUESTIONNAIRE, Cardol 215 naire: the Impact on Participation and Autonomy (IPAQ). Clin Rehabil 1999;13: Polit DF, Hungler BP. Nursing research. Principles and methods. 6th ed. Philadelphia: Lippincott Williams & Wilkins; De Bruin AF, Diederiks JPM, De Witte LP, Stevens FCJ, Philpsen H. The development of a short generic version of the Sickness Impact Profile. J Clin Epidemiol 1994;47: Post MWM, De Bruin AF, De Witte L, Schrijvers A. The SIP68: a measure of health-related functional status in rehabilitation medicine. Arch Phys Med Rehabil 1996;77: Van Der Zee KI, Sanderman R. Het meten van de algemene gezondheidstoestand met de RAND-36: een handleiding. Groningen: Noordelijk Centrum voor Gezondheidsvraagstukken; Ware JE. SF-36 physical and mental health summary scales: a user s manual. Boston: Health Institute; Harwood RH, Ebrahim S. Manual of the London Handicap Scale. 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J Clin Epidemiol 1989;42: Jenkinson C. Evaluating the efficacy of medical treatment: possibilities and limitations. Soc Sci Med 1995;41: Kersten P, Mullee MA, Smith JAE, McLellan L, George S. Generic health status measures are unsuitable for measuring health status in severely disabled people. Clin Rehabil 1999;13: Van Den Bos GAM. The value of data on disability in surveys. J Rehabil Sci 1994;7: Suppliers a. SPSS 8.0 statistical software; SPSS Inc, 233 S Wacker Dr, 11th Fl, Chicago, IL b. StatXact, version 3.0; Cytel Software Corp, 675 Massachusetts Ave, Cambridge, MA APPENDIX: THE IMPACT ON PARTICIPAQTION AND AUTONOMY QUESTIONNAIRE Response options per item: very good, good, fair, poor, very poor. Response options for problem experience: no problems, minor problems, severe problems Autonomy indoors (n 7) 1. My chances of getting around in my house where I want 2. My chances of getting around in my house when I want 3. My chances of washing, bathing or showering, and dressing, the way I wish, either by myself or with help are 4. My chances of having a bath and dressing when I want to, either by myself or with help are 5. My chances of getting up and going to bed when I want 6. My chances of going to the toilet when I need 7. My chances of eating and drinking when I want Family role (n 7) 1. My chances of contributing to looking after my home the way I want 2. My chances of getting minor housework jobs done, either by myself or by someone else the way I want them done are 3. My chances of getting major housework jobs done, either by myself or by others, the way I want them done are 4. My chances of getting housework done, either by myself or by others, when I want them done are 5. My chances of getting minor repairs and maintenance work done in my house, either by myself or by others, the way I want them done are 6. My chances of fulfilling my role at home as I would like are 7. My chances of spending my own money as I wish are Autonomy outdoors (n 5) 1. My chances of visiting relatives and friends when I want 2. My chances of going on the sort of trips and holidays I want to go on are 3. My chances of seeing people as often as I want are 4. My chances of living life the way I want are 5. My chances of spending leisure time the way I want Social relations (n 6) 1. My chances of talking to people close to me on equal terms are 2. The quality of my relationship with people who are close to me is 3. The respect I receive from people who are close to me is 4. My chances of having an intimate relationship are 5. My relationships with acquaintances are 6. The respect I receive from acquaintances is

7 216 IMPACT ON PARTICIPATION AND AUTONOMYQUESTIONNAIRE, Cardol Paid work and education (n 6) 1. My chances of doing the paid work I want to do are 2. My chances of doing my job the way I want 3. My contacts with the people I work with are 4. My chances of maintaining or changing my working role as I would wish are 5. My chances of getting a different job are 6. My chances of getting the training or education I want are Items addressing problem experience (n 8) 1. With regard to your mobility, to what extent does your 2. With regard to your self-care, to what extent does your 3. With regard to your family role, to what extent does your 4. With regard to controlling your finances, does your health or disability cause problems? 5. With regard to your leisure time, to what extent does your 6. With regard to your relationships, to what extent does your 7. With regard to paid work, to what extent does your health or disability cause problems? 8. With regard to your education, to what extent does your