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 rs = 0.00-0.69 and internal consistency was 0.85 (Cronbach's alpha). The NQ correlated moderately with cACT/ACT (rs = -0.54) and PAQLQ subscales Symptoms, Activity limitation and Emotional function, rs -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.