Sponge EEG is equivalent regarding signal quality, but faster than routine EEG.

Objective: Emergency diagnostics, such as acquisition of an electroencephalogram (EEG), are of great diagnostic importance, but there is often a lack of experienced personnel. Wet active electrode sponge-based electroencephalogram (sp-EEG) systems can be applied rapidly and by inexperienced personnel. This makes them an attractive alternative to routine EEG (r-EEG) systems in these settings. Here, we examined the feasibility and signal quality of sp-EEG compared to r-EEG.

Methods: In this case-control, single-blind, non-randomized study, EEG recordings using a sp- and a r-EEG system were performed in 18 individuals with a variety of epileptiform discharges and 11 healthy control subjects. The time was stopped until all electrodes in both systems displayed adequate skin-electrode impedances. The resulting 58 EEGs were visually inspected by 7 experienced, blinded neurologists. Raters were asked to score physiological and pathological graphoelements, and to distinguish between the different systems by visual inspection of the EEGs.

Results: Time to signal acquisition for sp-EEG was significantly faster (4.8 min (SD 2.01) vs. r-EEG 13.3 min (SD 2.72), p < 0.001). All physiological and pathological graphoelements of all 58 EEGs could be identified. Raters were unable to distinguish between sp-EEG or r-EEG based on visual inspection of the EEGs alone.

Conclusions: Sp-EEG represents a feasible alternative to r-EEG in emergency diagnostics or resource-limited settings.

Significance: Given shortage of trained personnel or resources, the easy implementation and comparable quality of a novel sp-EEG system may increase general availability of EEG and thus improve patient care.