Translation and validation of the Individualised Neuromuscular Quality of Life scale for the Spanish population: quality of life assessment for persons with neuromuscular diseases

The Individualized Neuromuscular Quality of Life (INQoL) is a questionnaire that evaluates the quality of life related to the health of adults with neuromuscular diseases. To validate and analyze the reliability of the Spanish version of the INQoL scale as an instrument for measuring quality of life related to health in individuals with neuromuscular diseases. A translation-back translation of the INQoL in the Spanish population is performed and, subsequently, for the analysis of reliability, two measurements are carried out; test retest, with 50 patients aged between 19 and 67 years. In this way we assess the intraobserver concordance and assess the internal consistency of the scale. The study of the reliability of the intraobserver concordance index has a value of excellent in seven of the ten subdimensions as well as in the total score of the quality of life. It has a value of good in two and of moderate in one subdimension. The analysis of Cronbach's alpha for the subdimensions of the INQoL has a value of excellent (> 0.818) in seven of them, as well as in the total score of the quality of life related to health (0.928), a value of good internal consistency in three of the subdimensions, and of moderate in one. The Spanish version of the INQoL is a valid and reliable instrument as a tool for measuring quality of life in adult patients with neuromuscular diseases.