Title: Development and Content Validation of the Pediatric Dizziness Index (PDI)

Abstract

Background Approximately, 3 million children are impacted by dizziness nationally, and as a result are at a greater risk of intellectual and learning disability. Given the wide variations between children and adults in brain morphology, maturity, and perceptions of injury impact, valid, age-specific patient reported outcome measures are crucial to capture the breadth of disability from dizziness. The purpose of this study was to develop and examine content validity of the PDI to evaluate activity limitation and participation restriction due to dizziness. Methods This was a cross sectional, observational study conducted primarily at an academic institute. Eight pediatric clinical and research content experts participated in the Modified Delphi Process. PDI was developed in four steps: 1) item development, 2) item evaluation, 3) content validity ratio and index calculation, and 4) cognitive interviews to ensure face validity, and comprehension of the items. A comprehensive literature search and review of the International Classification of Functioning, Disability and Health- Children and Youth model was conducted to identify potential items. Content validation process followed the COnsensus based Standards for the selection of health status Measurement Instruments (COSMIN) guidelines. Six children (8–16 years) participated in the cognitive interviewing. Content validity ratio (CVR) was calculated using Lawshe’s formula CVR = (ne – N/2)/N/2 (ne = number of experts identified an item as essential; N = total number of experts). Finally, content validity index (CVI) was calculated (CVI > 0.8 indicated good content validity). Results After two rounds of modified Delphi process, the initial item bank of 33 items was condensed to 10 items in final version of PDI. Three items on the PDI were revised post cognitive testing. The final version of PDI demonstrated good content validity (CVI = 0.87). Conclusion PDI is the first comprehensive patient reported measure specific to dizziness and provides evidence of strong content validity. Further research to establish factor structure and construct validity is recommended.