Protocol for a Modified Delphi Consensus Study on the * Clinical Assessment of Children with Suspected Olfactory Dysfunction

Background Olfactory dysfunction (OD) affects approximately 22% of the general population, yet children account for only around 2% of specialist olfactory clinic attendees -- a striking disparity that likely reflects systematic under-detection rather than lower disease prevalence. There are currently no internationally endorsed clinical guidelines governing the assessment of children with suspected OD. A recent international survey of 167 paediatric otolaryngologists across 36 countries found that more than half never perform psychophysical olfactory testing, a majority routinely order neuroimaging, and that multidisciplinary collaboration is largely lacking - findings that collectively motivate this consensus effort. Materials and Methods This is a prospectively registered, multi-round modified Delphi consensus study. A steering committee of seven international experts spanning paediatric otorhinolaryngology, chemosensory science, neuropaediatrics, and research methodology will generate an initial set of candidate consensus statements across 12 pre-defined clinical domains, derived from a structured narrative evidence review and practice-gap data. A panel of 15-25 international experts will vote anonymously over two to three sequential rounds using a 9-point Likert scale. Consensus is defined a priori as a median score [≥]7 with [≥]75% of panellists rating 7-9 and an IQR of [≤]2. A post-Delphi virtual ratification meeting will follow voting rounds. Patient and Public Involvement (PPI) is embedded throughout: a family advisory group of 4-6 parents, caregivers, and young people with lived experience of paediatric OD, recruited in partnership with anosmie.org, will review candidate statements before Round 1, and PPI findings will inform statement framing before expert voting begins. This study was assessed using the Health Research Authority (HRA) online decision tool for England and found not to require NHS Research Ethics Committee (REC) review. The study will be conducted in accordance with the Research Governance Framework for Health and Social Care (2nd Edition). Discussion The final consensus statements and supporting methodology will be submitted for peer-reviewed publication. The study will be reported in compliance with the ACCORD and DELPHISTAR reporting standards for consensus methods. The protocol has been pre-registered prospectively on the Open Science Framework (OSF) prior to data collection.