Diagnostic yield of electroencephalographyin the emergency department: protocol for the EMINENCE-M multicentre retrospective observational study.

introductionEmergency EEG (emEEG) is increasingly used in the emergency department (ED), but its diagnostic yield remains uncertain. This protocol describes a multicentre observational study aiming to evaluate emEEG findings and their relationship with diagnostic pathways and therapeutic management of patients admitted to the ED. METHODS AND ANALYSIS: This multicentre retrospective study will analyse emEEGs performed on patients admitted to the ED of some Italian teaching and community hospitals over a 1-year period with a target sample size of 3850 patients. The diagnostic yield of emEEG will be evaluated by assessing abnormal and epileptiform findings and the relationship between emEEG findings and subsequent clinical decisions, including confirmation or revision of the initial diagnostic suspicion, decisions regarding home discharge or hospitalisation and medication changes. EEG will be classified according to the terminology of the American Clinical Neurophysiology Society. Clinical and instrumental data will be respectively reviewed by emergency physicians and neurologists/neurophysiologists. In particular, via traditional biostatistics and interpretable machine learning models, the study will evaluate the diagnostic yield of emEEG and its association with subsequent clinical management across defined clinical scenarios in the ED. ETHICS AND DISSEMINATION: This first large-scale multicentre protocol will provide valuable insights for emergency department (ED) clinicians in selecting appropriate candidates for an emergency EEG (emEEG), supporting ethically sound, proportionate use of this resource in a time- and risk-critical setting. By clarifying diagnostic yield and its relationship with subsequent clinical decisions, the study is expected to generate robust evidence to guide emEEG ordering, reduce unnecessary testing and delays, and promote safer, more equitable decision-making (including appropriate home discharge) while minimising potential harms from misdiagnosis or overtreatment. The study has been approved by the Ethics Committee Regione Toscana - Area Vasta Centro (n. 27241). Findings will be disseminated through peer-reviewed publications, conference presentations and engagement with relevant clinical societies to inform international recommendations and facilitate translation into ED practice. Furthermore, developed models will be made openly available for external and public validation.