Clinical NeuroscienceA novel hydrogel electrolyte extender for rapid application of EEG sensors and extended recordings

ObjectiveDense-array EEG recordings are now commonplace in research and gaining acceptance in clinical settings. Application of many sensors with traditional electrolytes is time consuming. Saline electrolytes can be used to minimize application time but recording duration is limited due to evaporation. In the present study, we evaluate a NIPAm (N-isopropyl acrylamide:acrylic acid) base electrolyte extender for use with saline electrolytes.MethodsSensor-scalp impedances and EEG data quality acquired with the electrolyte extender are compared with those obtained for saline and an EEG electrolyte commonly used in clinical exams (Elefix).ResultsThe results show that when used in conjunction with saline, electrode-scalp impedances and data across the EEG spectrum are comparable with those obtained using Elefix EEG paste.ConclusionsWhen used in conjunction with saline, the electrolyte extender permits rapid application of dense-sensor arrays and stable, high-quality EEG data to be obtained for at least 4.5 h.SignificanceThis is an enabling technology that will make benefits of dense-array EEG recordings practical for clinical applications.

Highlights► Quality of EEG data acquired with a novel hydrogel electrolyte extender is equivalent to standard paste-electrolyte for up to 4.5 h. ► This technology removes a costly, time barrier associated with electrode preparation in dense-array EEG recordings while maintaining high quality EEG data over an extended time period. ► Removal of this barrier enables dense-array EEG recordings to be performed routinely in both research and clinical settings.