ADAPTATION OF THE MODIFIED BARTHEL INDEX FOR USE IN PHYSICAL MEDICINE AND REHABILITATION IN TURKEY

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1 Scand J Rehab Med 2000; 32: ADAPTATION OF THE MODIFIED BARTHEL INDEX FOR USE IN PHYSICAL MEDICINE AND REHABILITATION IN TURKEY Ayse A. Küçükdeveci, 1 Günes Yavuze, 1 Alan Tennant, 2 Nuben Süldü, 1 Bikan Sonel 1 and Tansu Aasil 1 Fom the 1 Depatment of Physical Medicine & Rehabilitation, Faculty of Medicine, Univesity of Ankaa, Ankaa, Tukey, and 2 Rheumatology & Rehabilitation Reseach Unit, School of Medicine, Univesity of Leeds, Leeds, UK The aim of this study was to adapt the modified Bathel Index fo Tukey and to detemine its eliability and validity. Afte the tanslation pocedue, 50 stoke patients and 50 spinal cod injuy patients, undegoing inpatient ehabilitation wee assessed by the newly adapted index at admission and dischage. Reliability was tested using intenal consistency, inte-ate eliability and the intaclass coelation coefficient. Constuct validity was assessed by association with impaiments (Bunnstom moto stages in stoke, Ameican Spinal Injuy Association moto/sensoy scoes and impaiment scale in spinal cod injuy) and by Rasch analysis. Intenal consistency was good at 0.93 fo stoke, and 0.88 fo spinal cod injuy. The level of ageement between two ates was sufficient with Kappa levels of above 0.5 fo spinal cod injuy and above 0.6 fo stoke. Inta-class coelation coefficients wee 0.99 and 0.77 fo stoke and spinal cod injuy, espectively. The newly adapted index showed expected associations with the impaiment scales, confiming its constuct validity. Howeve, Rasch analysis showed that bladde and bowel items compomise unidimensionality. In conclusion, adaptation of the modified Bathel Index has been successful and it can be used in Tukey as long as its limitations ae ecognized. Key wods: ehabilitation, outcome, Rasch, Bathel Index, disability. Scand J Rehab Med 2000; 32: Coespondence addess: Ayse A. Küçükdeveci, Gökkusagi Sitesi, Mo Blok, 12/25, Kaakusunla Ankaa, Tukey. ayse@tepa.com.t (Accepted Octobe 11, 1999) plan placement; to estimate cae equiements; and to detemine compensation (3). Many scales have been developed and utilized to detemine functional independence (1, 4). Each instument has its own unique application, fomat, advantages and disadvantages, as discussed in seveal ecent excellent citical eviews (2, 3, 5, 6). Among many available assessment scales, the Bathel Index (BI) is one of the most popula (7). Fo many yeas it has been the mainstay of measuing functional ability in ehabilitation. It has been utilized both in the management of individual patients, and in the evaluation of the efficacy of vaious ehabilitation pogams (8 12). The BI has ten items and the values assigned to each item ae based on the amount of physical assistance equied to pefom the task, being summed to give a total scoe anging fom 0 to 100 (0: fully dependent; 100: fully independent). In the oiginal vesion, each item is scoed in thee steps (7). A modified Bathel Index (MBI) with a five-step scoing system, developed by Shah et al. (13) was found to achieve a geate sensitivity and impoved eliability compaed with the oiginal vesion. The impotance of functional evaluation has been inceasingly ecognized among the ehabilitation medicine specialists in Tukey ove the last decade. Thus, intenationally accepted measues fo the assessment of functional disability have been used, especially in clinical eseach (14 16). Diffeent centes have used diffeent instuments afte tanslating them into Tukish. Howeve, these tanslations wee neithe popely adapted to Tukish cultue no tested fo validity and eliability. The BI has been one of the most widely used of these instuments. The aim of this study was to adapt the MBI fo the Tukish population and to detemine its eliability and validity. INTRODUCTION One of the pimay clinical objectives in ehabilitation medicine is to educe disability (1). Measuement of functional independence in patients with disabilities is an essential component of the ehabilitation pocess and has a vaiety of applications both in patient cae and clinical eseach (2). The puposes of such an assessment ae to povide objective and quantitative measues of patient function; to descibe and communicate levels of ability in self-cae and mobility skills; to monito changes in clinical status; to guide management decisions; to evaluate teatment efficacy; to pevent additional disability; to pedict pognosis; to PATIENTS AND METHODS Tanslation pocedue Fou health pofessionals (thee medical doctos and one physiotheapist) and an English teache who had been educated in the USA took pat in the tanslation pocess. The fist autho (AK) had had consideable expeience of ating the MBI while woking in a UK ehabilitation unit. This autho was one of the tanslatos and was subsequently involved in the taining pocess of the two MBI ates. Five Tukish people who wee fluent in English theefoe did independent liteal tanslations. The fist tanslated vesion was then discussed with a lay panel. Beyond the liteal tanslation, a conceptual tanslation was found to be necessay fo two of the items, as some of the activities explained in MBI wee not identical within the Tukish setting. Bathing was accepted as washing all ove eithe in a bath o in a showe o on a chai. Using toilet activity 2000 Taylo & Fancis. ISSN

2 88 A. A. Küçükdeveci et al. included not only the westen type of toilets with sitting closets but also the easten type with floo closets that equie squatting down on the heels. Afte the tanslation pocess, the ates (GY and BS) wee tained on the application of the MBI and applied the instument to a goup of 18 patients undegoing neuological ehabilitation in hospital as a test of face validity. Some modifications wee felt to be necessay fo the adaptation. Fo example some activities that opeationalize items such as cutting the meat, o opening the milk caton, wee not applicable to some patients. Cutting the bead and beaking the bead into pieces with finges wee thus added to desciptive activities associated with the fouth step of the feeding item. Cleaning the face with a piece of wet and soapy cloth if given by the helpe was common among patients with limited mobility, and this activity was included in the fouth step of the pesonal hygiene item. Afte these modifications, the final vesion was documented. Design and setting Fo the eliability and the validity studies, two diagnostic goups, patients with stoke and spinal cod injuy (SCI) wee ecuited. Consecutive patients with stoke and SCI admitted fo ehabilitation to the Depatment of Physical Medicine and Rehabilitation at the Medical Faculty of Ankaa Univesity, Tukey, fom 1993 to 1997 wee assessed using the adapted measue. The assessments wee undetaken by the same two ates involved in the ealie pilot study. Each patient was assessed at admission by the two ates and at dischage only by the fist ate (GY). Additional measues assessing impaiment wee applied concuently. Moto impaiment in stoke goup was evaluated accoding to the Bunnstom Moto Recovey Stages in 7 stages, indicating Stage 1 the highest impaiment, Stage 7 no impaiment (17). The degee of impaiment in SCI goup was gaded by the Ameican Spinal Cod Injuy Association (ASIA) Impaiment Scale, and the ASIA moto and the ASIA sensoy scoes wee also ecoded fo the detailed evaluation of moto and sensoy functions (18). Assessment of eliability Reliability is the consistency of a measue fom one use to the next. This is outinely tested by test-e-test eliability amongst patients who ae stable on the elevant constuct, and by intenal consistency. In addition, whee the scoe aises fom a pofessional who ates the patient, then inte-ate eliability is also impotant. Reliability of the Tukish vesion of MBI was detemined by testing the latte two, intenal consistency and inte-ate eliability. Intenal consistency was tested by Conbach s alpha (a) coefficient (19). This has taditionally been used as a measue of eliability and the extent to which items compising a scale measue the same concept. Recent wok has shown that while a can be used as an indication of the connectedness of items within a scale, it does not confim unidimensionality (20). Indeed, it is quite possible to have two o moe dimensions in a lage item set which nevetheless give a high a. Intenal consistency using a is thus no guide as to whethe o not the items of a scale belong to a single undelying constuct. Inte-ate eliability was assessed by the Kappa statistic (21). This is a atio of the popotion of times the ates agee, coected fo chance ageement, to the maximum popotion that the ates could agee, coected fo chance (22). Assessment of validity Validity is concened with whethe the instument measues the chaacteistic it pupots to measue. Whee thee is no gold standad against which to contast an instument, constuct validity is assessed. Hee the instument is contasted against othe measues whee thee would be an expected level of ageement (convegent validity) o disageement (divegent validity) (23). Some evidence that the items in the instument do measue a single constuct would also be sought. Constuct validity of the tanslated vesion of the MBI has been assessed in two ways. The fist, taditionally, by compaing the convegent validity of the instument with the impaiment measues fo both diagnostic goups. Although impaiments do not necessaily give ise to limitation in activities (disability), a modeate to stong association (>0.4) would be expected in the context of an acute ehabilitation wad. Secondly, a moe ecent innovation, by fit of the data to the one-paamete Item Response Theoy (Rasch) model. The Rasch Table I. Modified Bathel Index (MBI) scoes of patients with stoke (n = 50) Admission measuement model assumes that the data fom an instument ae unidimensional (24). Thus the model can be used to test whethe the items in the scale do belong to a single undelying constuct (25). Testing the fit of the data to the Rasch model is equivalent to a test of the theoetical constuct validity and adequacy of the scale (26). The data deived fom the MBI wee thus fitted to the Rasch model, opeationalized by the unconditional maximum likelihood appoach (27). Data wee analysed using the Statistical Package fo the Social Sciences (SPSS) (28), and a Rasch-Model Compute pogam BIGSTEPS (29). RESULTS Dischage Tansfe (0 15) (3) (10) Ambulation (0 15) (3) (12) Stais (0 10) (0) (5) Feeding (0 10) (5) (8) Dessing (0 10) (2) (5) Pesonal hygiene (0 5) (3) (4) Bathing (0 5) (1) (1) Use toilet (0 10) (2) (8) Bladde (0 10) (10) (10) Bowel (0 10) (10) (10) Total MBI (39) (69) Fifty patients with stoke and 50 with SCI wee assessed. The mean age of the stoke goup was 58 yeas and 74% wee female. The mean length of time since the stoke was 2.8 months, anging fom 1 to 10 months. All had unilateal hemiplegia, 44% of which wee ight-sided. Mean age of the SCI goup was 31.5 yeas and 56% wee female. Mean time since the injuy was 3.6 months, anging between 1 and 24 months. The level of the injuy was cevical in 22%, thoacic in 46% and lumba in 32%. Psychometic popeties of the tanslated MBI MBI scoes of patients with stoke and SCI ae pesented at Tables I and II. MBI scoes wee significantly inceased at Table II. Modified Bathel Index (MBI) scoes of patients with spinal cod injuy (n = 50) Admission Dischage Tansfe (0 15) (3) (8) Ambulation (0 15) (0) (5) Stais (0 10) (0) (0) Feeding (0 10) (8) (10) Dessing (0 10) (2) (8) Pesonal hygiene (0 5) (3) (5) Bathing (0 5) (1) (3) Use toilet (0 10) (0) (5) Bladde (0 10) (0) (5) Bowel (0 10) (0) (8) Total MBI (21) (51)

3 Modified Bathel Index in Tukey 89 Table III. Inte-ate eliability of Modified Bathel Index* SCI Stoke Tansfe Ambulation Stais Feeding Dessing Pesonal hygiene Bathing Use toilet Bladde Bowel Total * Kappa. dischage in both goups compaed with the admission levels (p < 0.001, Wilcoxon signed anks test). Reliability of the MBI. The intenal consistency of the MBI was tested by Conbach s alpha (a). At admission a was and upon dischage fo the stoke goup. Fo the SCI goup, a values wee 0.88 and 0.90 at admission and dischage, espectively. This suggests a consideable degee of connectedness of items in the scale with an acceptable level of intenal consistency fo both diagnostic goups. Inte-ate eliability esults of MBI in both diagnostic goups ae pesented at Table III. The level of ageement between the two ates was sufficient, eflected by Kappa levels above 0.5 with SCI and above 0.6 with stoke. Oveall ageement was good as expessed by the inta-class coelation coefficients of 0.77 in SCI and 0.99 in stoke. Convegent validity of the MBI. In SCI goup, total MBI scoe was found to be significantly elated to ASIA Impaiment Scale at both admission (Kuskal Wallis test, p = 0.005) and at dischage (p = 0.003). Coelation between the MBI scoes and the ASIA moto-sensoy scoes ae pesented in Tables IV and V. As expected, coelation of MBI with moto function was stonge than the coelation with sensoy function. These data suppoted the convegent validity of the new vesion fo the patients with SCI. In the stoke goup, distibution of the Bunnstom stages upon admission necessitated vaying levels of aggegation fo analytical puposes (Table VI). MBI scoes wee significantly elated to both lowe and uppe extemity Bunnstom stages (Kuskal Wallis, p < 0.01) and to hand function at admission but only to lowe and uppe extemity moto stages at dischage. Table IV. Coelation between Modified Bathel Index (MBI) and Ameican Spinal Injuy Association (ASIA) scoes* Admission Dischage MBI-ASIA moto MBI-ASIA sensoy * Speaman coelation analysis. p < p < Table V. Coelation of Ameican Spinal Injuy Association (ASIA) scoes with the items of Modified Bathel Index* ASIA Moto Tansfe Ambulation Stais Feeding Dessing Pesonal hygiene Bathing Use toilet Bladde Bowel * Speaman Coelation Analysis. ASIA Sensoy Table VI. Fequency of Bunnstom Moto stages at admission Scoe/Level Hand Uppe Lowe Total Constuct validity of the MBI by Rasch model. Within each diagnostic goup the data fom the MBI wee fitted to the Rasch patial cedit model (30). Table VII shows the fit of the 10 items fo stoke patients. Items ae odeed by thei level of difficulty, thus fo this goup of patients, climbing a flight of stais independently, dessing and ambulation ae the most difficult, wheeas independence in bladde and bowel will be the most easy to achieve (if not aleady independent upon admission). Fit of the items to the Rasch model is shown by two fit statistics, the infit and outfit statistics. Acceptable values fo infit and outfit ae within the ange The items bladde and bowel show consideable levels of misfit, as detemined by the OUTFIT statistic. OUTFIT is concened with esponses to items Table VII. Fit of admission Modified Bathel Index items to Rasch model in stoke goup Item Difficulty Eo Infit Outfit Point-biseial Stais Dessing Ambulation Use toilet Tansfe Bathing Feeding Pesonal hygiene Bladde Bowel Total

4 90 A. A. Küçükdeveci et al. Table VIII. Fit of admission Modified Bathel Index items to Rasch model in the spinal cod injuy goup Item Difficulty Eo Infit Outfit Point-Biseial Stais Use toilet Bathing Bladde Ambulation Bowel Tansfe Dessing Pesonal hygiene Feeding Total that ae fa emoved fom the pesons ability level. Thus some patients with a high level of disability will nevetheless have no poblems with bladde and bowel, and vice vesa. This eflects the discodance between impaiment and disability. If this analysis was concened with the development of a new scale, then these items would be omitted as they do not appea to measue the same constuct (disability) as the othe items. The hieachical odeing of items fo SCI goup as shown in Table VIII ae diffeent fom that fo stoke. Stais emains the most difficult item, while toiletting, bathing and bladde items follow in the ode of difficulty in achieving independence. Dessing and gooming ae the easiest items. Thus the items mak consideably diffeent levels of disability on the undelying constuct in two diagnostic goups. This pecludes a diect compaison of disability levels between these two goups. Bladde and bowel items continue to show levels of misfit to the undelying constuct fo patients with SCI. DISCUSSION The pesent study descibes the adaptation of the MBI (13) fo the Tukish neuo-ehabilitation patients. Two impaiment goups; stoke and spinal cod injuy wee chosen fo the eliability and the validity studies of the new vesion. Both diagnostic goups had consideably low MBI scoes at admission and showed significant inceases at dischage (Tables I and II), as would be expected fom those undegoing ehabilitation. The intenal consistency of the MBI in this study is satisfactoy, as shown by Conbach s alpha coefficients of 0.93 fo stoke and 0.88 fo SCI on admission. These findings wee consistent with pevious epots (8, 13). Inteate eliability of the Tukish MBI has poven to be adequate as expessed by the inta-class coelation coefficients of 0.77 in SCI and 0.99 in stoke. Although the level of ageement between the two ates was consideably good in stoke goup, confiming othe findings (31, 32), it could not each the same high level fo SCI goup. This might be due to the difficulty of ating some items (dessing, tansfe, bladde and bowel) in SCI. Fo example, ating both uppe and lowe body dessing in one item may cause confusion as a patient with SCI might be quite dependent in dessing the uppe body wheeas might have some difficulties in the lowe body. The level of assistance that a patient with SCI equies might change accoding to the place of tansfe (chai, toilet o bath) and this may also cause confusion while ating tansfe in SCI whee it is much easie to ate in stoke. Rating both the accidents and the assistance equied with the devices in the same level of activity fo bladde and bowel items may be difficult fo ates as these two functions may not be in concodance in SCI. Howeve this is not a poblem fo patients with stoke as they ae usually continent o may have an occasional accident (33, 34). As a matte of fact the kappa values of those fou items wee consideably low in SCI compaed with stoke. Relationship between the physical disability and the neuological impaiment in stoke has been investigated in vaious studies. Coelation coefficients between the BI and the stoke scales showing the seveity of neuological impaiment wee epoted to be aound 0.70 (35). Some authos demonstated significant associations of BI with am and leg moto function (33, 35). Shah et al. showed that admission Bunnstom stages wee highly coelated with dischage BI (36). In the pesent study, convegent validity of the newly adapted measue was assessed by investigating the elation with the impaiment levels in both patient goups. In stoke goup, MBI scoes wee significantly elated to lowe extemity, uppe extemity and to hand functions at admission, but only to lowe and uppe extemity functions at dischage. This expected finding suppoted the convegent validity in stoke goup, as simila esults had been epoted peviously (35, 37), validating the statement that stoke patients ae able to achieve independence in ADL without a coesponding impovement in am and hand ecovey; i.e. the patients may compensate by pefoming ADLs with one-handed techniques. Pevious studies on patients with SCI, aiming to detemine the factos that pedict functional outcome has evealed that completeness of the spinal cod lesion, level of injuy and moto function wee significant pedictos of Bathel scoe at dischage (38 40). Convegent validity of the Tukish MBI in SCI goup has been theefoe confimed by the demonstation of both significant elation with completeness of injuy (ASIA impaiment scale) and significant coelations with moto and sensoy functions. Rasch analysis has emeged as a useful technique to evaluate instuments that ae intended to measue scaled behaviou, including disability (24, 34, 41). The constuct validity of the newly adapted MBI was examined by Rasch analysis and the esults eveal that the hieachical odeing of the items ae not the same in two diagnostic goups. Howeve the elative difficulty of items between these goups paallels the actual natue of these goups medical condition, suppoting the validity of the measuement system. Fo example, the bladde and bowel items ae elatively easie to achieve independence with stoke but elatively hade to achieve in SCI. Also, dessing with one hand is elatively difficult fo a hemiplegic,

5 Modified Bathel Index in Tukey 91 while paaplegics may have fewe poblems while dessing. Ove thee-quates (78%) of ou SCI goup had thoacal/lumba injuies and thus they wee expected to have less poblems with dessing. Diffeences in the hieachical odeing of items pevent diect compaison between diffeent diagnostic goups. These ae new lessons that ae being leaned fom the application of Rasch analysis and appea to apply to most health status measues, including the FIM (34). Of cucial impotance fo coss-cultual studies, the hieachical odeing of items fo stoke in the adaptation fo Tukey is simila to that in the UK (42). The items stais, ambulation, dessing, toiletting and tansfe, as well as bladde and bowel, ae odeed (within one standad eo) in the same way as the UK vesion. Howeve, bathing is quite diffeent, and may eflect the changes that wee made to the opeating instuctions fo assignment to this item. In the UK vesion, bathing was the most difficult item upon which to achieve independence in a neuological ehabilitation wad, wheeas in Tukey it is an item of almost aveage difficulty. Bladde and bowel items showed consideable levels of misfit to the undelying constuct fo both diagnostic goups. This level of misfit on these items is consistent with othe findings on the MBI (42). The lack of in unidimensionality of the scale can compomise the esponsiveness of the instument. Fo the MBI, bladde and bowel is essentially a measue of the pesence o absence of the incontinence, and its fequency, athe than the management of incontinence. As such, the bladde and bowel items (impaiments) may be invaiant fo most patients with SCI, but some patients with stoke may be expected to ecove this function. Thus having items which measue two dimensions may obscue the tue change on the dimension of inteest, in this case disability. CONCLUSION The adaptation of the MBI has demonstated adequate levels of eliability, both intenal consistency and inte-ate eliability, as well as convegent constuct validity. Thee is some doubt about the unidimensionality of items given misfit to the Rasch model. Howeve, this has been found in the UK vesion, and thus is an inheent weakness of the scale, athe than a esult of the Tukish adaptation. The pocess of liteal and conceptual tanslation of the instument has shown not to be a sufficient condition fo coss-cultual validity. Adapting a measue to meet local cultual needs has been shown to shift the difficulty levels of some items and thus ende coss-cultual compaisons invalid, e.g. a scoe of 50 in the Tukish vesion would not imply the same level of disability in the same tasks as the English vesion. Othe limitations fo use, fo example between diagnostic goups, ae also likely to be found acoss cultues, just as the weakness of the constuct with espect to the bowel and bladde items has been shown elsewhee. Thus the instument can be used in Tukey in the field of neuological ehabilitation as long as these limitations ae acknowledged. ACKNOWLEDGEMENTS We gatefully acknowledge the financial suppot of the Bitish Council fo the collaboation of the authos. A shot vesion of this pape was pesented at the II Mediteanean Congess of Physical Medicine & Rehabilitation, May 1998, Valencia, Spain. REFERENCES 1. Wade DT. Measuement in neuological ehabilitation. Oxfod: Oxfod Univesity Pess, Roth E, Davidoff G, Haughton J, Adne M. Functional assessment in spinal cod injuy: a compaison of the Modified Bathel Index and the adapted Functional Independence Measue. Clin Rehab 1990; 4: Feinstein AR, Josephy BR, Wells CK. Scientific and clinical poblems in indexes of functional disability. 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