Validation of the Paediatric Nijmegen Questionnaire in Sweden: A Self‐Screening Tool for Dysfunctional Breathing

Background The Nijmegen Questionnaire (NQ) is used to identify Dysfunctional Breathing (DB) in individuals with asthma. However, it has not been validated for use in children and adolescents. Objective This study aimed to validate a Swedish NQ for this population. Methods Participants aged 10–17 years with asthma were included ( n = 124). In Cohort I ( n = 22), audiotaped semi‐structured interviews were conducted to adapt and refine the questionnaire analyzed by qualitative content analysis, resulting in NQ version 1. Forty‐eight participants (11 from Cohort I, 37 new) then completed version 1 to assess internal redundancy, consistency (Spearman's Rho, Cronbach's alpha) and item clarity, leading to version 2. Cohort II ( n = 60 new) completed NQ version 2 alongside the Paediatric Asthma Quality of Life Questionnaire (PAQLQ) and Childhood/Adult Asthma Control Test (cACT/ACT) to assess construct validity. Cohort III ( n = 54, 48 from Cohort II, 6 new) completed NQ version 2 again after 2 weeks for test–retest reliability. Results Content analysis prompted revisions for clarity and relevance. Internal redundancy ranged from r s = 0.00–0.69 and internal consistency was 0.85 (Cronbach's alpha). The NQ correlated moderately with cACT/ACT (r s = −0.54) and PAQLQ subscales Symptoms, Activity limitation and Emotional function, r s −0.52, −0.48, −0.39 (CI 0.32;0.70, 0.24;0.66, 0.14;0.60) respectively. Test–retest reliability was 0.86 (Kw) ( p < 0.0001). Conclusion The Swedish Paediatric NQ seems to be a valid and reliable tool for identifying DB in children and adolescents with asthma.