Facial disability index (FDI): Adaptation to Spanish, reliability and validity

Med O al Pa ol O al Ci Bucal. 2012 No 1;17 (6):e1006-12. Facial disabili y index e1006 Jou nal sec ion: O al Su ge y Publica ion Types: Resea ch Facial disabili y index (FDI): Adap a ion o Spanish, eliabili y and alidi y Edua do Gonzalez-Ca de o 1, Ped o In an e-Cossio 2, Au elio Cayuela 3, Manuel Acos a-Fe ia 4, Jose-Luis Gu ie ez-Pe ez 2 1 Residen , Depa men o O al and Maxillo acial Su ge y, Vi gen del Rocio Uni e si y Hospi al, Se ille, Spain 2 P o esso , Depa men o O al and Maxillo acial Su ge y, Vi gen del Rocio Uni e si y Hospi al, Se ille, Spain 3 Public Heal h Technician, Sou h Heal h Dis ic , Se ille, Spain 4 S a Su geon, Depa men o O al and Maxillo acial Su ge y, San a Lucia Uni e si y Hospi al, Ca agena (Mu cia), Spain Co espondence: Depa men o O al y Maxilo acial Su ge y Vi gen del Rocio Uni e si y Hospi al A . Manuel Siu o . 41013-Se ille, Spain pin an [email protected] Recei ed: 06/11/2011 Accep ed: 07/02/2012 Abs ac Objec i es: To adap o Spanish he acial disabili y index (FDI) desc ibed by VanSwea ingen and B ach in 1995 and o assess i s eliabili y and alidi y in pa ien s wi h acial ne e pa esis a e pa o idec omy. S udy Design: The p esen s udy was conduc ed in wo di e en s ages: a) c oss-cul u al adap a ion o he ques- ionnai e and b) c oss-sec ional s udy o a con ol g oup o 79 Spanish-speaking pa ien s who su e ed acial pa esis a e supe icial pa o idec omy wi h acial ne e p ese a ion. The c oss-cul u al adap a ion p ocess com- p ised he ollowing s ages: (I) ini ial ansla ion, (II) syn hesis o he ansla ed documen , (III) e o- ansla ion, (IV) e iew by a boa d o expe s, (V) pilo s udy o he p e- inal d a and (VI) analysis o he pilo s udy and inal d a . Resul s: The eliabili y and in e nal consis ency o e e y one o he a ing scales included in he FDI (C onbach’s alpha coe icien ) was 0.83 o he comple e scale and 0.77 and 0.82 o he physical and he social well-being subscales. The analysis o he ac o ial alidi y o he main componen s o he adap ed FDI yielded simila esul s o he o iginal ques ionnai e. Bi a ia e co ela ions be ween FDI and House-B ackmann scale we e posi i e. The a iance pe cen age was calcula ed o all FDI componen s. Conclusions: The FDI ques ionnai e is a speci ic ins umen o assessing acial neu omuscula dys unc ion which becomes a use ul ool in o de o de e mine quali y o li e in pa ien s wi h acial ne e pa alysis. Spanish adap ed FDI is equi alen o he o iginal ques ionnai e and shows simila eliabili y and alidi y. The p o en ep oducibi- li y, eliabili y and alidi y o his ques ionnai e make i a use ul addi ional ool o e alua ing he impac o acial ne e pa alysis in Spanish-speaking pa ien s. Key wo ds: Pa o idec omy, acial ne e pa alysis, acial disabili y. Gonzalez-Ca de o E, In an e-Cossio P, Cayuela A, Acos a-Fe ia M, Gu ie- ez-Pe ez JL. Facial disabili y index (FDI): Adap a ion o Spanish, eliabili y and alidi y. Med O al Pa ol O al Ci Bucal. 2012 No 1;17 (6):e1006-12. h p://www.medicinao al.com/medo al ee01/ 17i6/medo al 17i6p1006.pd A icle Numbe : 18054 h p://www.medicinao al.com/ © Medicina O al S. L. C.I.F. B 96689336 - pISSN 1698-4447 - eISSN: 1698-6946 eMail: [email p o ec ed] Indexed in: Science Ci a ion Index Expanded Jou nal Ci a ion Repo s Index Medicus, MEDLINE, PubMed Scopus, Embase and Emca e Indice Médico Español doi:10.4317/medo al.18054 h p://dx.doi.o g/doi:10.4317/medo al.18054 Med O al Pa ol O al Ci Bucal. 2012 No 1;17 (6):e1006-12. Facial disabili y index e1007 In oduc ion Facial ne e pa alysis is he main complica ion o su gi- cal ea men o pa o id gland umo s. As a esul , p e- se a ion o acial ne e unc ion is a key objec i e in his ype o in e en ion. Se e al s udies on acial ne e unc ion ollowing pa o idec omy show ha a empo- a y pa alysis o pa esis is common and occu s in be- ween 17 and 64.4% o pa ien s (1-5), wi h an incidence o pe manen pa alysis anging be ween 0 and 5.5%. Al hough he acial ne e is kep in ac a e su ge y, pa- ien s expe ience a acial pa esis o ansien ne e pa aly- sis which usually has a s ong unc ional and socio-labo al impac in hem. Pa ien s equen ly complain o impai ed speech, di icul y ea ing, di icul y closing eyelids and/o lips, aes he ic de o mi y o he ace, d ibbling, e c. Symp- oms imp o e g adually in days o weeks un il comple e eco e y o acial ne e unc ion is achie ed. Quali y o li e in ela ion o acial ne e pa alysis e e s o he subjec- i e assessmen pa ien s make o di e en aspec s o hei daily li e which a ec hei heal h condi ion be o e hey ge he ull unc ionali y o he acial ne e. Quali y o li e is assessed by means o a se ies o ques- ionnai es o scales which include i ems o ques ions dis- ibu ed in o domains o ields and which a e analysed ei he indi idually o globally. Gene al ques ionnai es o measu e quali y o li e like he SF-36 (Sho Fo m 36 Heal h Su ey) o he HRLQ (Heal h Rela ed Quali y o Li e) and e en o he head and neck-speci ic su eys ha e no p o ed use ul o disc imina e he ue di icul ies ex- pe ienced by pa ien s wi h acial mobili y diso de s. The Facial Disabili y Index (FDI; in Spanish IDF, Ín- dice de Discapacidad Facial) (6) is an ins umen wide- ly used in a g ea numbe o s udies which has no been adap ed o Spanish and whose aim is o assess speci ic quali y o li e seconda y o al e a ions o acial mimi- c y. The FDI is a sho , sel - epo ques ionnai e deal- ing wi h psychosocial and physical impai men aspec s associa ed wi h acial neu omuscula unc ion. The e is no o he speci ic ins umen in he Spanish language o e alua e pa ien s wi h acial pa alysis a e pa o id su ge y which allows physicians o ca y ou bo h he diagnosis o pa esis e ec s and he ea ly and long- e m ollow up o such impai men . Taking in o accoun his scena io, he aim o ou s udy has been o adap he o iginal FDI de ised by VanSwea ingen and B ach in 1995 (6) o ou linguis ic and cul u al milieu, ansla - ing i in o Spanish and pe o ming he anscul u al a- dap a ion in o de o p o ide, no only a speci ic ool o assess acial pa esis a e pa o id gland su ge y bu also o e alua e i s impac on he quali y o li e o pa ien s and e alua e he neu omuscula diso de s a ec ing a- cial mimic y. Ma e ial and Me hods In a p elimina y s age we pe o med a li e a u e sea ch o he 10 yea s p e ious o he onse o ou s udy in o - de o es ablish a ansla ion p o ocol consis en wi h he la es epo s published on his subjec . The main esea che con ac ed ia e-mail he c ea o s o he ques- ionnai e and ob ained hei consen o ca y ou he s udy. -S udy s ages The p esen s udy was conduc ed in wo di e en s ag- es: 1) c oss-cul u al adap a ion o he FDI ques ionnai e and 2) c oss-sec ional s udy in a con ol g oup o assess i s eliabili y and alidi y. The anscul u al adap a ion was ca ied ou using he ansla ion- e o ansla ion echnique (7-10). P io o any s ep in he p ocess, he c ea o s o he FDI ga e hei consen o he de elopmen o he p esen s udy and we e in i ed o ake pa in i . The wo ansla o s en olled o he s udy we e wo bilingual ce i ied ans- la o s whose i s o mo he ongue is Spanish and ha e Ame ican English as second language. They we e es- ponsible o ansla ing he o iginal FDI om Ame i- can English in o Spanish (s ep 1). Bo h ansla o s a ed he di icul y o ind he concep ual equi alen s in he ansla ion in a scale om 1 (minimum di icul y) o 10 (maximum di icul y). Then, one o he esea che s and an ex e nal expe econciled bo h ansla ions, ha is, hey analysed and compa ed he di e ences be ween hem in o de o app o e a inal Spanish d a (s ep 2). In o de o assess he co ec ness o he ansla ion, he ag eed e sion was in u n e o ansla ed in o Ame i- can English (s ep 3) by a bilingual speake (Ame ican English as mo he ongue and Spanish as second lan- guage), who did no know abou he ques ionnai e in i s o iginal ongue. T ansla o s we e asked o make a con- cep ual and no a li e al ansla ion. In a ollowing s ep, he e o ansla ion and he o iginal we e compa ed (s ep 4) analysing di e ences and con adic ions and an almos de ini i e Spanish e sion was w i en. The com- pa ison c i e ia we e: di e en , when he esul ing i em los i s o iginal meaning; li e al, when he esul was iden ical o he o iginal and simila o concep ual, when some wo d changed i s meaning bu he concep o he ques ionnai e was main ained. I ems we e e ised and modi ied acco ding o he esea che s’ c i e ia in o de o sol e disc epancies. The nex s ep was o pe o m an analysis o he comp ehensibili y and equi alence o he inal e sion submi ing i o he es o 20 pa ien s wi h acial pa esis a e pa o idec omy (s ep 5). A e he eal applica ion in pa ien s, he las equi ed modi ica ions we e made and he de ini i e adap ed FDI was ob ained (s ep 6). The ield su ey was conduc ed om 2008 h ough 2010 on a se ies o pa ien s admi ed in he O al and Maxillo acial Su ge y Depa men , Vi gen del Rocio Uni e si y Hospi al, Se ille (Spain). The Resea ch and E hics Commi ee o he hospi al ga e hei consen o Med O al Pa ol O al Ci Bucal. 2012 No 1;17 (6):e1006-12. Facial disabili y index e1008 pe o m he s udy. Inclusion c i e ia we e: inciden ca- ses co esponding o diagnosed pa ien s no ye ea ed o a benign umo in he supe icial lobe o he pa o id gland con i med by means o his ological examina ion by a ine needle aspi a ion biopsy o he umo al issue and an imaging s udy (CT/MRI), and pa ien s eligible o abla i e umo su ge y by means o supe icial pa- o idec omy wi h p ese a ion o he acial ne e. Ex- clusion c i e ia we e: pa ien s wi h a p e ious his o y o idiopa hic acial pa alysis o who su e ed om i a he momen o he s udy, su gical sec ion o one o mo e b anches o he acial ne e du ing su ge y esul ing in pe manen pa alysis, p e ious his o y o ce eb o as- cula acciden s, psychia ic o psychomo o diso de s which p e en he in e iew wi h he pa ien , illi e acy and egula esidence ou side he in luence a ea o he hospi al ( empo a y esiden s); we did no conside he le el o educa ion. Du ing he p e-su ge y isi , pa ien s we e in o med o hei pa icipa ion in he s udy; hey ecei ed he ques ionnai es, an acknowledgemen le e , w i en in o ma ion abou he p ojec and he in o med consen . -Ques ionnai e The FDI (Fig. 1) is in e na ionally alida ed sho - o m PHYSICAL FUNCTION SUBSCORE ITEM 1 How much di icul y did you ha e keeping ood in you mou h mo ing ood a ound in you mou h o ge ing ood s uck in you cheek while ea ing? ITEM 2 How much did you ha e d inking om a cup? ITEM 3 How much di icul y did you ha e saying speci ic sounds while speaking? ITEM 4 How much di icul y did you ha e wi h you eye ea ing excessi ely o becoming d y? ITEM 5 How much di icul y did you ha e wi h b ushing you ee h o insing you mou h? SOCIAL FUNCTIONING AND WELL-BEING SUBSCORE ITEM 6 How much o he ime ha e you el calm and peace ul? ITEM 7 How much o he ime did you isola e you sel om people a ound you? ITEM 8 How much o he ime did you ge i i able owa ds hose a ound you? ITEM 9 How o en did you wake up ea ly o wake up se e al imes du ing you nigh ime sleep? ITEM 10 How o en has you acial unc ion kep you om going ou o ea shop o pa icipa e in amily o social ac i i- ies? Fig. 1. O iginal e sion o he FDI. ques ionnai e ga he ing in o ma ion ela ed o he im- pac o acial pa alysis and he physical and social well- being impai men i p o okes. I is a speci ic, sho and simple ques ionnai e easy o be illed in by pa ien s, comp ising 10 i ems o ques ions dis ibu ed in o wo subscales: physical and social well-being (6). The high- e he sco e ob ained in he ques ionnai e, he be e he quali y o li e o he pa ien . The aim is o assess dis- abili y and he ou come o any in e en ion in e ms o a signi ican change in he physical disabili y and social well-being o pa ien s. -Analysis Conside ing ha all pa ien s esponded o 100% o he i ems, he easibili y and accep abili y o he ins umen we e aken o g an ed. We analyzed he ollowing as- pec s o he ansla ed ques ionnai e: The alidi y o he ques ionnai e was analysed using he ac o ial analysis o he main componen s. The aim was o iden i y eme ging and unde lying ac o s which become e iden when we y o g oup he i ems o ques- ions answe ed by pa ien s in he same di ec ion (11). We analysed he co ela ions ound in he answe s o he ansla ed ques ionnai e. This s a is ical analysis was used o iden i y he numbe o dimensions in a g oup o mul i a ia e i ems showing he con ibu ion o each i em o he speci ic dimension unde s udy. Reliabili y was de ined as in e nal consis ency (homo- genei y) o he o e all ques ionnai e and o i s subscales, calcula ing C onbach’s alpha coe icien o e e y one o hem. C onbach’s alpha coe icien is he adjus ed mean o he co ela ions be ween i ems o ques ions included in he scale. The expec ed alpha coe icien was es ima- ed a 0.70; so i was conside ed ha alpha alues abo e han his alue we e su icien o ensu e he eliabili y o he scale and o conside ha he ins umen would calcula e consis en and s able measu emen s. In o de o es he cons uc alidi y o he ansla ed ques ionnai e, we assessed he ela ionship be ween he esul s o he ansla ed ques ionnai e which e alua ed pa ien s’ disabili y and hei ue physical impai men using he in e na ional House-B ackmann scale (H-B) (12). This scale is a widely- alida ed s anda d me hod Med O al Pa ol O al Ci Bucal. 2012 No 1;17 (6):e1006-12. Facial disabili y index e1009 (13) o measu e acial ne e unc ion, con ol i s e o- lu ion o e ime, and assess eco e y and e ec s a e ea men . H-B scale classi ies he deg ee o pa esis in o 6 le els, om I (no pa esis) o VI ( o al pa esis). The o al sco e is ob ained by adding he esul o each o he 5 b anches in he acial ne e, hus ob aining an in e al o alues which may ange om 6 o 36. Pea son’s co - ela ion coe icien was used o de e mine such bi a ia e co ela ion. The esul o each o he subscales ob ained in he ac o ial analysis o he main componen s was compa ed wi h he physical examina ion. Finally, we de e mined whe he he speci ic ansla ed ques ionnai e p o ed mo e alid han o he gene al ins- umen s measu ing quali y o li e which ha e al eady been ansla ed in o Spanish and a e widely alida ed and employed. In o de o do so, we compa ed he FDI and he SF-36 su ey (14) once we had asked he © 2011 Quali yMe ic o he equi ed pe mission. The SF-36 su ey is a s anda dized sel - epo ins umen includ- ing 8 dimensions. We used he physical dimension o compa e i wi h he H-B scale. Pea son’s co ela ion co- e icien was used o such pu pose. Ou hypo hesis was o es ablish he lack o co ela ion o a sligh co ela ion be ween he SF-36 su ey and he H-B scale, compa ing i wi h he co ela ion be ween he FDI, he physical subscale o he SF-36 su ey and he H-B scale. A alue o p<0.05 was conside ed s a is- ically signi ican . Da a we e analysed using he so - wa e package SPSS .15.0 o Windows. Resul s F om Janua y 2008 h ough Decembe 2010 we ca ied ou a p ospec i e s udy o he da a co esponding o 79 SUBESCALA FUNCIONAMIENTO FÍSICO ITEM 1 ¿Cuán a di icul ad ha enido pa a gua da la comida en la boca, mo e la comida den o de la boca o man ene comida a ni el de los ca illos mien as come? ITEM 2 ¿Cuán a di icul ad ha enido en bebe de un aso? ITEM 3 ¿Cuán a di icul ad ha enido en deci sonidos especí icos mien as habla? ITEM 4 ¿Cuán a di icul ad ha enido espec o al lag imeo excesi o o sequedad en sus ojos? ITEM 5 ¿Cuán a di icul ad ha enido en la a se los dien es o en enjuaga se la boca? SUBESCALA FUNCIONAMIENTO SOCIAL Y BIENESTAR ITEM 6 ¿Cuán o iempo se sien e anquilo o calmado? ITEM 7 ¿Cuán o iempo se aísla de la gen e que le odea? ITEM 8 ¿Cuán o iempo se ha no ado i i ado hacia la gen e que es á a su al ededo ? ITEM 9 ¿Con qué ecuencia se le an a p on o o se despie a a ias eces du an e el sueño? ITEM 10 ¿En cuán as ocasiones su unción acial e i a que salga a come , de iendas, o le impide su pa ici- pación en ac i idades amilia es o sociales? Fig. 2. Spanish adap ed e sion o he FDI. pa ien s who had unde gone conse a i e supe icial pa o idec omy wi h p ese a ion o he acial ne e o pleomo phic adenoma o he pa o id gland supe icial lobe and me he inclusion c i e ia. Mean age o pa ien s was 40 y s in an in e al be ween 24 and 81 y s. Pa- ien s we e handed he FDI ques ionnai e h ee mon hs a e he in e en ion. The di icul y o he ansla ion was a ed by 2 ansla- o s wi h a mean sco e o 3. In he end, once he de ini- i e adap a ion was e alua ed we ob ained he comple e equi alence in all he i ems in he ques ionnai e. Figu e 2 shows he inal ansla ion o each o he ques ions in he FDI. Fo example, some changes we e in oduced in i em 1, “How much di icul y did you ha e keeping ood in you mou h, mo ing ood a ound in you mou h o ge ing ood s uck in you cheek while ea ing?”, which was ansla ed in o Spanish as “¿Con qué di icul ad ha man enido la comida en la boca, ha mo ido la comida en el in e io de u boca o ha apa ado la comida a un lado de la boca mien as comías?”. Ne e heless, he inal adap a ion was: “¿Cuán a di icul ad ha enido pa a gua da la comida en la boca, mo e la comida den o de la boca o man ene comida a ni el de los ca illos mien as come?”. Likewise, i em 4: “How much di - icul y did you ha e wi h you eye ea ing excessi ely o becoming d y?”, was ansla ed as “¿Con qué di i- cul ad sus ojos han lag imeado excesi amen e o se han secado?”, bu he inal adap a ion: “¿Cuán a di icul ad ha enido espec o al lag imeo excesi o o sequedad en sus ojos?”, was less con using o pa ien s and ex- plained mo e clea ly he physical diso de i a emp ed o measu e (eye hyd a ion in pa ien s wi h pa esis o he oph halmic b anch o he acial ne e). Med O al Pa ol O al Ci Bucal. 2012 No 1;17 (6):e1006-12. Facial disabili y index e1010 Reliabili y was measu ed using C onbach’s alpha co- e icien bo h o he comple e scale and o he wo dimensions (physical and social well-being unc ions) es ablished by he analysis o he main componen s. The da a ob ained showed adequa e eliabili y a 3 mon hs a e su ge y. C onbach’s alpha coe icien was 0.83 o he comple e scale and 0.77 and 0.82 o he physical and social well-being subscales, espec i ely. In an a emp o imp o e homogenei y, we calcula ed C onbach’s co- e icien excluding in each case one o he i ems. Fo all and e e y one o he i ems we ob ained lowe eliabili y le els han o he global scale (Table 1). Excluded i em C onbach´s alpha coe icien 10,82 20,82 30,81 40,80 50,82 60,79 70,78 80,78 90,81 10 0,82 Table 1. Assessmen o eliabili y and in e - nal consis ency (C onbach’s alpha coe icien ) o he adap ed FDI, excluding each one o he i ems. As ega ds he analysis o he main componen s, we ca ied ou a ac o ial analysis wi h Va imax o a ion and ac o ex ac ion wi h an eigen alue >1; ha is, he analysis o he componen s should show mo e a iance in he o e all ins umen han any o he i ems in he ques ionnai e. This analysis con i med ha he i ems included in he physical subscale o med a homogene- ous g oup, clea ly apa om he social well-being sub- scale. Table 2 highligh s hose alues >0.5 showing he sepa a ion be ween he i s componen (physical sub- scale) and he second one (social well-being subscale). The SF-36 su ey was illed in by 34 pa ien s. Table 3 shows bi a ia e co ela ions be ween FDI and H-B scale, and be ween SF-36 su ey (physical unc ion dimension) and H-B scale. As we expec ed, when we compa ed he esul s o he FDI wi h he ue physical dys unc ion o he pa ien measu ed by means o he H-B scale, we obse ed a s a is ically signi ican co - ela ion be ween he physical subscale and he clinical diagnosis o acial pa esis measu ed by means o he H-B scale (Table 3, i em a). The analysis o he co ela- Componen 1 2 IDF 1 -,053 ,876 IDF 2 ,271 ,788 IDF 3 ,156 ,647 IDF 4 ,415 ,677 IDF 5 ,245 ,592 IDF 6 ,823 ,183 IDF 7 ,719 ,428 IDF 8 ,804 ,282 IDF 9 ,739 ,291 IDF 10 ,626 -,026 Table 2. Analysis o he main componen s o he FDI us- ing o a ed componen ma ix ( ac o ex ac ion me hod wi h analysis o main componen s and Kaise Va imax o a ion). Componen 1: physical subscale. Componen 2: social well-being subscale Values > 0.5 a e indica ed in bold ion be ween he o al FDI and he H-B scale e ealed a lowe co ela ion han he one obse ed wi h he physi- cal subscale on i s own (Table 3, i em b). As we hypo h- esized, a di ec ela ion was no obse ed be ween he physical scale in he SF-36 su ey and he ue physical unc ion o he pa ien measu ed by means o he H-B scale (Table 3, i em c), he way i is obse ed in he case o FDI (physical subscale). Table 4 shows he analysis o a iance pe cen age e- ealed by each o he FDI componen s, which coincides wi h he alida ion o he o iginal ins umen . The a i- ance pe cen ages o he i s and second componen s we e 31.12 and 29.96, espec i ely. Discussion The esul s o he p esen s udy sugges ha he Spanish adap ed FDI is equi alen o he o iginal ques ionnai e and shows simila eliabili y and alidi y as well as simi- la limi a ions. C onbach’s alpha coe icien s o he scales and dimensions o he adap ed FDI a e simila o hose o he o iginal ques ionnai e wi h alues anging om 0.70 o 0.90. In o de o boos he esea ch we ha e conduc ed a p ospec i e s udy o homogeneous inciden cases, all o hem wi h he same ype o umo in he same ana omical loca ion and ea ed wi h he same su gical echnique. As ega ds eliabili y, he FDI assessed quali y o li e accu a ely and wi h adequa e in e nal alidi y. Reliabil- i y su passes 0.7 (0.83), a le el conside ed adequa e o ca y ou compa isons and o moni o ize acial disabil- i y in he same pa ien wi h sel - epo ins umen s and shows a deg ee o in e nal consis ency simila o ha ob ained by means o o he ques ionnai es which com- Med O al Pa ol O al Ci Bucal. 2012 No 1;17 (6):e1006-12. Facial disabili y index e1011 To al H-B FDI: physical subscale FDI: social well-being subscale To al H-B Pea son’s co ela ion (bila e al) signi icance 1(a) ,405(**) ,001 … FDI: physical subscale Pea son’s co ela ion (bila e al) signi icance ,405(**) ,001 1,464(**) ,000 FDI: social well-being subscale Pea son’s co ela ion (bila e al) signi icance 1,41 ,272 ,464(**) ,000 1 O e all FDI Pea son’s co ela ion (bila e al) signi icance (b) ,264** ,001 --- --- SF-36 Pea son’s co ela ion Physical dimension (0-100) (bila e al) signi icance (c) ,134 ,449 (n=34) ,435(*) ,010 (n=34) ,361(*) ,036 (n=34) Table 3. Bi a ia e co ela ions be ween he FDI, H-B scale and SF-36 su ey. ** 0,01 (bila e al) accoun s o signi ican co ela ion FDI Componen Ini ial sel - alues Sums o squa es o ac o ex ac ion sa u a ions Sum o squa es o a ion sa u a ions To al Va iance % Accumula ed % To al Va iance % Accumula ed % To al Va iance % Accumula ed % 14,635 46,345 46,345 4,635 46,345 46,345 3,112 31,123 31,123 21,475 14,747 61,092 1,475 14,747 61,092 2,997 29,969 61,092 Table 4. Va iance pe cen age exp essed o each one o he FDI componen s. Componen 1: physical subscale. Componen 2: social well-being subscale p ise he same numbe o i ems (15). This con i ms ha he in e nal alidi y o he ques ionnai e has no been al e ed by he ansla ion p ocess. Unlike he o iginal ins umen (6), we obse e a sligh ly lowe eliabili y in he physical dimension (0.77) han in he social well- being dimension (0.82), al hough in iew o he small di e ence i is no conside ed ele an . In any case, bo h alues a e alid o s a e he eliabili y o he FDI. To ca y ou ac o ial analysis, we ha e used a di e en sample han o pe o m he alida ion o he o iginal ins umen , as a as size, sampling echnique, language and cul u e a e conce ned. Bo h samples a e he e oge- neous and comp ise di e en ypes o people and he sampling echnique has been non p obabilis ic, as i is no a equi emen o alida ion. The e o e, as he e- sul s ob ained a e simila o hose ob ained in he analy- sis o he o iginal ques ionnai e, we can a i m ha he ques ionnai es measu e he same, despi e he di e- ences be ween he samples. Simila i y is obse ed in bo h ac o g oups, almos iden ical, which con i ms he hypo hesis ha he c oss-cul u al adap a ion does no al e he ques ionnai e. A e calcula ing C onbach’s al- pha coe icien disca ding 1 i em in each case, we ound ha he global scale o he FDI was e en mo e eliable o he o e all ins umen han o each isola ed i em. Taking in o accoun he lack o a s anda dized measu e- men o acial pa esis, we used H-B scale o alida e he cons uc (12). Such alidi y has been p o ed o he co ela ion be ween he FDI and he clinical measu e- men o acial mo emen (Table 3). This co ela ion also con i med he concep ual ela ionship be ween dys- unc ion and disabili y, which unde lies acial unc ion eco e y. The expec ed co ela ion was highe be ween he physical subscale and he H-B scale (0.405) (Table 3, i em a) in compa ison wi h a global measu emen o he FDI and he H-B scale (0.264) (Table 3, i em b), which suppo s he alidi y in he subscales o ma . Howe e , ag eeing wi h ou hypo hesis, unlike he case wi h he ansla ed ques ionnai e, no co ela ion was obse ed be ween he physical dimension o he SF-36 Med O al Pa ol O al Ci Bucal. 2012 No 1;17 (6):e1006-12. Facial disabili y index e1012 su ey and he clinical measu emen o acial pa esis. This may be explained by he lack o speci ici y o his la e su ey o e alua e acial neu omuscula dys unc- ion (Table 3, i em c). The SF-36 su ey has no p o ed use ul in he e alua ion and ollow-up o pa ien s as i measu es di e en aspec s o physical disabili y and ocuses on o he heal h p oblems apa om acial neu- omuscula dys unc ion. The Spanish ansla ed and adap ed FDI ope a es as a speci ic ques ionnai e p o iding aluable in o ma ion o e alua e acial neu omuscula dys unc ion. The ob- jec i e assessmen o quali y o li e in ela ion o acial unc ion using alida ed ins umen s may play a key ole in he diagnosis and ollow up o ou pa ien s (16). In his sense, he FDI can be i s ly used as a diagnos ic ins umen and in a subsequen s age as a ollow-up ool a e ea men o su ge y (6). The FDI is a sho , simple and easy sel - epo ins umen which can be adminis- e ed in abou 4 minu es. I has been widely accep ed by pa ien s, as he ansla ion is comp ehensible and is adap ed o Spanish language. Resea che s ha e ne e been equi ed o explain he i ems o ques ions du ing he comple ion o he ques ionnai e and physicians ha e ne e complained abou incomp ehensible exp essions o di icul y in i s use. Due o he simplici y o mos o he i ems in he ques- ionnai e, a li e al ansla ion was p e e ed o hal o hem (i ems numbe 2,3,5,7 and 8) and a concep ual one o he o he hal (i ems numbe 1,4,6,9 and 10). The ansla ions made sepa a ely by he bilingual ansla- o s showed almos no di e ences when compa ed. The desc ip i e, clea and concise language o he o iginal ques ionnai e a o ed he almos comple e ag eemen be ween ansla o s. Unde no ci cums ance has he meaning o he ques ions been modi ied in o de o main ain he objec o he ques ion in he o iginal ins- umen . Nei he has i been conside ed app op ia e o c ea e any new i em o modi y he meaning o any o hem. Du ing he pilo s udy and du ing he alida ion p ocess, we ha e no ound any p oblem wi h he ques- ions; none o hem we e misleading o di icul o un- de s and. None o he pa ien s has equi ed any u he explana ion o ill in he o e all ques ionnai e. To sum up, he esul s o he p esen s udy show ha he Spanish adap ed FDI is eliable and alid ins umen bo h o esea ch and o applica ion in daily clinical p ac ice. I is a use ul ool o assess he impac o acial disabili y associa ed o acial pa alysis /pa esis ollow- ing pa o idec omy; i is accessible o Spanish speaking pa ien s and physicians in ol ed in he ea men and ollow-up o hese pa ien s. Fu u e wo k in his ield should ocus on he applica ion o his ins umen o an- alyze he di e en acial neu omuscula diso de s and o op imize he managemen , ea men and ehabili a- ion o acial pa esis o pa alysis in he long e m. Re e ences 1. Ha ney M, Walsh P, Conlon B, Hone S, Timon C. Pa o id gland su ge y: a e ospec i e e iew o 108 cases. 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BMJ. 1993;306:1440-4. 12. House JW, B ackmann DE. Facial ne e g ading sys em. O o- la yngol Head Neck Su g. 1985;93:146-7. 13. E ans RA, Ha ies ML, Baguley DM, Mo a DA. Reliabili y o he House and B ackmann g ading sys em o acial palsy. J La yn- gol O ol. 1989;103:1045-6. 14. Wa e JE, She bou ne CD. The MOS 36-i em sho - o m heal h su ey (SF-36). I. Concep ual amewo k and i em selec ion. Med Ca e. 1992;30:473-83. 15. Je e AM, Da ies AR, Clea y PD, Calkins DR, Rubens ein LV, Fink A, e al. The unc ional s a us ques ionnai e: eliabili y and a- lidi y when used in p ima y ca e. J Gen In e n Med. 1986;1:143-9. 16. P aena C espo M, Lo a Espinosa A, Aquino Llina es N, Sánchez Sánchez AM, Jiménez Co és A. The Spanish e sion o he New- cas le As hma Knowledge Ques ionnai e o pa en s o child en wi h as hma (NAKQ). T anscul u al adap a ion and eliabili y analysis. An Pedia (Ba c). 2009;70:209-17. Acknowledgmen s The au ho s wish o hank o Rocio Valdes-Galla do and Vic o ia P a s-Golcze o hei coope a ion wi h he collec ion o da a and especially o Jessi VanSwea ingen (Uni e si y o Pi sbu gh) o he aluable help in he e iew o he p esen pape . The p esen s udy has been gi en inancial suppo by he Ins i u o de Salud Ca los III-Fondo de In es igación Sani a ia (070048/2007), Minis e io de Sanidad y Consumo, España.