Document Type : Original Article
Authors
- Seyed Jalaleddin Hadei 1
- Payam Khomand 2
- Farzad Fatehi 3
- Vera Bril 4
- Carolina Barnett 4
- Shahriar Nafissi 1
1 Neuromuscular Research Center, Tehran University of Medical Sciences, Tehran, Iran Department of Neurology, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
2 Dalhousie University, Department of Neurology, Saint John Regional Hospital, Saint John, NB, Canada
3 Neuromuscular Research Center, Tehran University of Medical Sciences, Tehran, Iran Neurology Department, University Hospital of Leicester NHS Trust, Leicester, UK
4 Division of Neurology, Department of Medicine, University Health Network, Toronto, Canada
Abstract
Background: The Myasthenia Gravis Impairment Index (MGII) is a valid and reliable tool for assessing patients with myasthenia gravis (MG), originally developed in English. This study evaluates the validity, reliability, and responsiveness of a Persian translation of the MGII in Iran.
Methods: The MGII was translated through a multi-step process for cultural adaptation. Content validity was assessed via face validity, Content Validity Index (CVI), and Content Validity Ratio (CVR). Construct validity was evaluated by correlating MGII scores with the Myasthenia Gravis Composite (MGC), Quantitative Myasthenia Gravis (QMG) score, Myasthenia Gravis Activities of Daily Living Scale (MG-ADL), and 15-item Myasthenia Gravis Quality of Life (MGQOL-15). Test-retest reliability was assessed using the Intraclass Correlation Coefficient (ICC) in stable patients. Additionally, responsiveness was evaluated by comparing pre- and post-treatment MGII scores and their correlation with other measures.
Results: One hundred patients with MG participated in the study. The Persian version of the MGII demonstrated good face and content validity, excellent test-retest reliability (ICC > 0.90 for most scores), and good inter-rater reliability (ICC > 0.80). The floor effect was low at 4%. A significant improvement in total MGII score (-18.9 ± 12.6) was noted in 26 patients after treatment changes, with moderate to high correlations observed between changes in the MGII scores and changes in the MGC, QMG, MG-ADL, and MGQOL-15 scores.
Conclusion: This study exhibits the validity and reliability of the Persian version of MGII, supporting its use in assessing patients with MG and their response to treatment in the Iranian population.
Keywords
Main Subjects
- Oosterhuis HJ. The natural course of myasthenia gravis: a long term follow up study. J Neurol Neurosurg Psychiatry 1989; 52(10): 1121-7.
- Lazaridis K, Tzartos SJ. Autoantibody Specificities in Myasthenia Gravis; Implications for Improved Diagnostics and Therapeutics. Front Immunol 2020; 11: 212.
- Dresser L, Wlodarski R, Rezania K, Soliven B. Myasthenia Gravis: Epidemiology, Pathophysiology and Clinical Manifestations. J Clin Med 2021; 10(11): 2235.
- Regnault A, Morel T, De la Loge C, Mazerolle F, Kaminski HJ, Habib AA. Measuring Overall Severity of Myasthenia Gravis (MG): Evidence for the Added Value of the MG Symptoms PRO. Neurol Ther 2023; 12(5): 1573-90.
- Nafissi S, Okhovat AA, Sinaei F, Ansari B, Ayramloo H, Basiri K, et al. Iranian Consensus Recommendations for Treatment of Myasthenia Gravis. Arch Iran Med 2022; 25(1): 37-49.
- Wolfe GI, Herbelin L, Nations SP, Foster B, Bryan WW, Barohn RJ. Myasthenia gravis activities of daily living profile. Neurology 1999; 52(7): 1487-9.
- Bedlack RS, Sanders DB. On the concept of myasthenic crisis. J Clin Neuromuscul Dis 2002; 4(1): 40-2.
- Burns TM. History of outcome measures for myasthenia gravis. Muscle Nerve 2010; 42(1): 5-13.
- Mullins LL, Carpentier MY, Paul RH, Sanders DB. Disease-specific measure of quality of life for myasthenia gravis. Muscle Nerve 2008; 38(2): 947-56.
- Barnett C, Bril V, Kapral M, Kulkarni A, Davis AM. Development and validation of the Myasthenia Gravis Impairment Index. Neurology 2016; 87(9): 879-86.
- Barnett C, Bril V, Kapral M, Kulkarni AV, Davis AM. Myasthenia Gravis Impairment Index: Responsiveness, meaningful change, and relative efficiency. Neurology 2017; 89(23): 2357-64.
- De Meel RHP, Barnett C, Bril V, Tannemaat MR, Verschuuren J. Myasthenia Gravis Impairment Index: Sensitivity for Change in Generalized Muscle Weakness. J Neuromuscul Dis 2020; 7(3): 297-300.
- Pasqualin F, Barnett C, Guidoni SV, Albertini E, Ermani M, Bonifati DM. Validation of the Italian version of the Myasthenia Gravis Impairment Index (MGII). Neurol Sci 2022; 43(3): 2059-64.
- Jaretzki A 3rd, Barohn RJ, Ernstoff RM, Kaminski HJ, Keesey JC, Penn AS, et al. Myasthenia gravis: recommendations for clinical research standards. Task Force of the Medical Scientific Advisory Board of the Myasthenia Gravis Foundation of America. Neurology 2000; 55(1): 16-23.
- Ostovan VR, Fatehi F, Davoudi F, Nafissi S. Validation of the 15-item myasthenia gravis quality of life questionnaire (MG-QOL15) Persian version. Muscle Nerve 2016; 54(1): 65-70.
- Muscle Study Group. A trial of mycophenolate mofetil with prednisone as initial immunotherapy in myasthenia gravis. Neurology 2008; 71(6): 394-9.
- Barth D, Nabavi Nouri M, Ng E, Nwe P, Bril V. Comparison of IVIg and PLEX in patients with myasthenia gravis. Neurology 2011; 76(23): 2017-23.
- Guillemin F, Bombardier C, Beaton D. Cross-cultural adaptation of health-related quality of life measures: literature review and proposed guidelines. J Clin Epidemiol 1993; 46(12): 1417-32.
- Beaton DE, Bombardier C, Guillemin F, Ferraz MB. Guidelines for the process of cross-cultural adaptation of self-report measures. Spine (Phila Pa 1976) 2000; 25(24): 3186-91.
- Sperber AD. Translation and validation of study instruments for cross-cultural research. Gastroenterology 2004; 126(1 Suppl 1): S124-8.
- Barohn RJ, McIntire D, Herbelin L, Wolfe GI, Nations S, Bryan WW. Reliability testing of the quantitative myasthenia gravis score. Ann N Y Acad Sci 1998; 841: 769-72.
- Li M, Gao Q, Yu T. Kappa statistic considerations in evaluating inter-rater reliability between two raters: which, when and context matters. BMC Cancer 2023; 23(1): 799.
- Martínez Pérez JA, Pérez Martin PS. Coeficiente de correlación intraclase [Intraclass correlation coefficient]. Semergen 2023; 49(3): 101907.
- Almanasreh E, Moles R, Chen TF. Evaluation of methods used for estimating content validity. Res Social Adm Pharm 2019; 15(2): 214-21.
- Madadizadeh F, Bahariniya S. Tutorial on how to calculating content validity of scales in medical research. Perioper Care Oper Room Manag 2023; 31: 100315.
- Farmakidis C, Pasnoor M, Dimachkie MM, Barohn RJ. Treatment of Myasthenia Gravis. Neurol Clin 2018; 36(2): 311-37.
)