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Individualized Neuromuscular Quality of Life Questionnaire (INQoL)
Availability
Please visit this website for more information about the instrument:
Classification
Supplemental: Facioscapulohumeral muscular dystrophy (FSHD) and Myotonic Dystrophy (DM)
Short Description of Instrument
Originally developed and validated in the United Kingdom the Individualized Neuromuscular Quality of Life questionnaire (INQoL) is used to assess health related quality of life of individuals suffering from neuromuscular diseases (muscle disease and myotonic disorders). (Vincent et al., 2007) There are versions with additional symptom impact scores for diplopia, ptosis and dysphagia undergoing evaluation at the moment. (Han et al., 2022) The INQoL consists of 45 questions within 10 sections and is a neuromuscular disease specific quality of life measure for adults.
Comments/Special Instructions
Neuromuscular Quality of Life questionnaire (INQoL) is specific to muscle disease and unlike other QoL measures allows for individual variation. (Vincent et al., 2007) It is currently used to assess the disease burden in patients with various neuromuscular diseases. (Kacar et al., 2018) Landfeldt et al., 2019)
Scoring and Psychometric Properties
Scoring: The INQoL consists of 45 questions within 11 subscales. (Han et al., 2022) These subscales are classified into 3 dimensions.
 
The 'symptoms' dimension has seven subscales, weakness, locking, pain, fatigue, droopy eyelids, double vision, and swallowing difficulties, which are specific to neuromuscular disorders. The 'life domains' dimension has five sub-scales that look at the impact of NMD on particular areas of life: activities, independence, social relationships, emotions, and body image. Finally, the 'treatment effects' dimension, comprised of two subscales solicits the positive and negative effects of treatment both perceived and expected treatment effects. (Burns et al., 2012; Han et al., 2022; Vincent et al., 2007)
 
All INQoL items are scored on a 7-point Likert scale from 0 to 6 or from 1 to 7. The higher the subscale score, the greater the impact of the disease on the individual's symptoms or life domains.
 
Responses to items looking at symptoms and the impact of NMD on life domains are weighted by the perceived importance of the item, assigned by the participant. The final score is presented as a percentage of the maximum detrimental impact with a higher percentage indicating greater impact. (Vincent et al., 2007; Han et al., 2022)
 
Participants' perception of their treatment is represented by two scores which reflect the trade-off between the positive and negative effects of treatment now and in the future. Scores for each section can be presented as a profile and a composite score representing overall QoL, is calculated based on scores from the five sections which assess the impact of NMD on particular areas of life. (Burns et al., 2012;Vincent et al., 2007)
 
Psychometric Properties:
 
The INQoL has been validated for UK adults with a variety of muscle diseases that include congenital myopathies, limb-girdle muscular dystrophies, facioscapulohumeral muscular dystrophy, dystrophic and nondystrophic myotonias, and inflammatory myopathies. Vincent et al., (2007) verified the 45-items in the INQoL by a postal survey and test-retest, reliability, validity and responsiveness to change were all satisfactorily appraised. (Burns et al., 2012;Vincent et al., 2007)
Rationale/Justification
Strengths: The INQoL is specific to muscle disease and unlike other QoL measures allows for individual variation. (Vincent et al., 2007). The measure has been translated and validated in several countries, including the United States (Sadjadi et al., 2022), Italy (Sansone et al., 2010), the Netherlands (Seesing et al., 2015), Serbia (Peric et al., 2011), Spain (Fagoaga et al., 2017), Korea (Han et al., 2022) and Japan (Fujino et al., 2018).
 
Weaknesses:
A study by Sadjadi and colleagues showed that while "the INQoL is appropriate for use in US population there may be differences in the importance that US subjects attach to certain aspects of QoL that could be the basis for further study. If these differences are confirmed then this may have implications for the interpretation of QoL outcomes in multi-national trials." (Sadjadi et al., 2011)
References
Key References:
Rose M, Brooks V, Walburn J, Sanders D, Pandya S, Kissel J et al. Validation of the UK Individualised Neuromuscular Quality of Life measure for use in the USA. Neuromuscular Disorders 2006; 16 supplement: S176 (Abstract).
 
Vincent KA, Carr AJ, Walburn J, Scott DL, Rose MR. Construction and validation of a quality of life questionnaire for neuromuscular disease (INQoL). Neurology. 2007 Mar 27;68(13):1051-7.
 
Additional References:
Burns TM, Graham CD, Rose MR, Simmons Z. Quality of life and measures of quality of life in patients with neuromuscular disorders. Muscle Nerve. 2012 Jul;46(1):9-25.
 
Fagoaga J, Girabent-Farres M, Bagur-Calafat C. Traduccion y validacion de la escala Individualized Neuromuscular Quality of Life para la poblacion española: evaluacion de la calidad de vida para personas afectas de enfermedades neuromusculares [Translation and validation of the Individualised Neuromuscular Quality of Life scale for the Spanish population: quality of life assessment for persons with neuromuscular diseases]. Rev Neurol. 2017 Mar 1;64(5):194-200.
 
Fujino H, Saito T, Takahashi MP, Takada H, Nakayama T, Ogata K, Rose MR, Imura O, Matsumura T. Validation of The Individualized Neuromuscular Quality of Life in Japanese patients with myotonic dystrophy. Muscle Nerve 2018;58:56-63.
 
Han HJ, Lee SA, Choi YC, Rose MR, Park HJ. Validation of the Individualized Neuromuscular Quality of Life Questionnaire in Korean Patients With Genetic Neuromuscular Diseases. J Clin Neurol. 2022 Sep;18(5):514-521.
 
Kacar A, Bjelica B, Bozovic I, Peric S, Nikolic A, Cobeljic M, Petrovic M, Stojanov A, Djordjevic G, Vukojevic Z, Dominovic-Kovacevic A, Stojanovic M, Stevic Z, Rakocevic-Stojanovic V, Lavrnic D, Basta I. Neuromuscular disease-specific questionnaire to assess quality of life in patients with chronic inflammatory demyelinating polyradiculoneuropathy. J Peripher Nerv Syst. 2018 Mar;23(1):11-16.
 
Landfeldt E, Nikolenko N, Jimenez-Moreno C, Cumming S, Monckton DG, Gorman G, Turner C, Lochmüller H. Disease burden of myotonic dystrophy type 1. J Neurol. 2019 Apr;266(4):998-1006.
 
Moradi K, Jamal-Omidi S, Masoudi M, Bagheri S, Nafissi S, Fatehi F. Validation of Persian Individualized Neuromuscular Quality of Life in patients with muscular dystrophies. Curr J Neurol. 2020 Jan 5;19(1):13-9.
 
Peric S, Sansone V, Lavrnic D, Meola G, Basta I, Miljkovic M, et al. Serbian validation of the Individualized Neuromuscular Quality of Life Questionnaire (INQoL) in adults with myotonic dystrophy type 1. J Neurol Res 2011;1:153-160.
 
Rose M, Brooks V, Walburn J, Sanders D, Pandya S, Kissel J et al. Validation of a quality of life measure for myasthenia gravis. Neuromuscular Disorders 2006; 16 supplement: S152 (Abstract).
 
Sadjadi R, Vincent KA, Carr AJ, Walburn J, Brooks VL, Pandya S, Kissel JT, Jackson CE, Rose MR; Muscle Study Group. Validation of the individualised neuromuscular quality of life for the USA with comparison of the impact of muscle disease on those living in USA versus UK. Health Qual Life Outcomes. 2011 Dec 16;9:114.
 
Sansone VA, Panzeri M, Montanari M, Apolone G, Gandossini S, Rose MR, Politano L, Solimene C, Siciliano G, Volpi L, Angelini C, Palmieri A, Toscano A, Musumeci O, Mongini T, Vercelli L, Massa R, Panico MB, Grandi M, Meola G. Italian validation of INQoL, a quality of life questionnaire for adults with muscle diseases. Eur J Neurol. 2010 Sep;17(9):1178-1187.
 
Seesing FM, van Vught LE, Rose MR, Drost G, van Engelen BG, van der Wilt GJ. The individualized neuromuscular quality of life questionnaire: cultural translation and psychometric validation for the Dutch population. Muscle Nerve. 2015 Apr;51(4):496-500.
 
Document last updated October 2024