How to measure person-centred care in people living with ALS: development and validation of the patient experience PEMALS questionnaire

<i>Objective:</i> Person-centredness is a fundamental aspect of care for people with amyotrophic lateral sclerosis (plwALS). Systematic assessment of patient experiences is essential to reflect their perspectives and needs in care. This study aimed to develop and evaluate the psychometric properties of the Patient Experience Measure in ALS care (PEMALS), and to assess the care experience of Dutch plwALS. <i>Methods:</i> We developed a preliminary questionnaire based on literature and input from two representatives, each from a different patient association and three healthcare professionals. In an online survey study, plwALS from the population-based national registry were invited to complete the Dutch questionnaire twice within a 3-day interval. We evaluated test-retest reliability, structural validity, and internal consistency. After item reduction, a total PEMALS score was computed and analyzed for reliability, measurement error, and associations with demographic and clinical patient characteristics. <i>Results:</i> The preliminary questionnaire included 28 items and was completed by 245 plwALS. After item reduction, the final PEMALS contained 16 items. Factor analysis confirmed unidimensionality, with a Cronbach's α of 0.97. Test-retest reliability had an ICC of 0.81 (95% CI 0.72-0.87), and a measurement error of 0.43 points (scale 1 to 10). There was no systematic difference between test-retest (mean difference 0.02, 95% CI 0.05-0.10, <i>p</i> = 0.510). PlwALS rated ALS care with a median score of 9.6 (IQR 8.7-10); 31.4% scored the maximum. Older participants reported significantly higher PEMALS scores (Spearman's r = 0.199, <i>p</i> = 0.002). <i>Conclusions:</i> The PEMALS is a valid and reliable measure for assessing patient experience in ALS care and enables systematic monitoring of person-centered quality of care.