Quality of Life after Brain Injury in children aged six and seven years (QOLIBRI-KIDDY) – development and scale analysis of the first disease-specific self-report instrument for young children after traumatic brain injury

To date, there are no age-appropriate instruments for assessing the subjective impact of pediatric traumatic brain injury (TBI) sequelae on multiple domains of health-related quality of life (HRQoL) in young children. The present study therefore aims to develop and examine the psychometric properties of a new disease-specific, self-reported HRQoL instrument, the Quality of Life after Brain Injury for children aged 6-7 years (QOLIBRI-KIDDY). Questionnaire development included focus group interviews, cognitive debriefings, and Delphi expert panels. The pilot version of the instrument was tested in 72 children (6.00-7.92 years of age; 60% boys; 86% after mild TBI). After item reduction based on a confirmatory scale analysis considering the six-factor structure of the questionnaire versions for older children, adolescents, and adults (Cognition, Self, Daily Life & Autonomy, Social Relationships, Emotions, Physical Problems), its reliability and validity were investigated. The final version of the QOLIBRI-KIDDY comprises 23 items. Psychometric analyses indicated internal consistency to be satisfactory (ɑ = 0.49-0.72; ω = 0.57-0.78). Construct validity suggested the expected overlap between generic HRQoL and TBI-specific HRQoL (r = 0.17-0.36). There were small (r > 0.2) to moderate (r > 0.3) correlations between lower TBI-specific HRQoL and participants with lower learning rates, anxiety, depression, and post-concussion symptoms, particularly on the Cognition, Social Relationships, Emotions, and Physical Problems scales. The comparison of known groups revealed significant moderate and significant effects for lower HRQoL in children with depressive symptoms on the Emotions scale (d = - 0.46) and with post-concussion symptoms on the Cognition (d = - 0.42) and Social Relationships scales (d = - 0.56). The QOLIBRI-KIDDY is a comprehensive, yet economical tool, comparable in content and items to the other age-adapted QOLIBRI versions. Its application has the potential to provide longitudinal data on subjects after TBI from childhood to older age, with a subjective perspective that can contribute to improving the therapy, rehabilitation, and daily life of young children.