EEG in the Emergency Department: When the Neurophysiological Test Can Be Avoided in Emergency Diagnostic Workups? The EMINENCE Study.

Introduction: This study was conducted to determine whether specific emergency physician (EP) diagnoses and/or neurological signs/symptoms upon admission to the Emergency Department (ED) were associated with normal/non-informative emergency electroencephalogram (emEEG). Methods: Data from consecutive patients admitted to the ED of our tertiary hospital over a two-year period (1 January 2023-31 December 2024) were analyzed retrospectively. We evaluated the correlation between normal/non-specific emEEGs and EP admission diagnoses and neurological signs/symptoms on admission. Epileptic discharges and sharp waves with triphasic morphology were considered specific patterns. Results: A total of 2008 patients underwent emEEG recording during the study period. EmEEGs were considered non-informative in 100% of global amnesia diagnoses, 100% of cases of mild head trauma, 100% of cases of migraine with aura, 98.3% of transient ischemic attacks (TIAs), 95.6% of transient losses of consciousness (TLCs) when seizure was not the primary suspected diagnosis, and in 92.7% of falls of unknown dynamics. Epileptic patterns were detected in 4% of patients presenting with TLC and in 2.4% of those with falls of unknown dynamics, with approximately half of these patients having a pre-existing diagnosis of epilepsy. Triphasic waves were detected in 4.9% patients with falls of unknown dynamics, in 1.7% with TIA, and in 0.4% with TLC. All of these patients had fever/sepsis or metabolic/electrolyte disorders. Overall, across all clinical scenarios, emEEGs were considered non-informative in 385 (19.1%) tested patients. Conclusions: emEEGs are almost non-informative in the diagnostic pathway for patients with global amnesia, mild head trauma, and migraine with aura, and in patients with TIA, TLC, or falls of unknown dynamics. EPs can safely consider avoiding emEEGs in the absence of previous epilepsy diagnosis, fever/sepsis, metabolic/electrolyte disturbances, or drug abuse.