Abstracts

Rationale: A prototype dry electrode EEG system developed by Quantum Applied Science and Research (QUASAR), Inc. utilizes a dry electrode system that allows for acquisition of electroencephalographic (EEG) data without use of collodion or gels between the electrode and the scalp. The critical innovation of the sensors used in this device is the proprietary technology creating the ability to measure physiologic signals with large contact impedances, directly combined with a high input impedance amplifier built into the electrode. This system offers easy and quick application and could be used for an EEG telemedicine project whereby non-EEG technologist staff at remote clinics could acquire EEG and transfer it to central site for interpretation.Methods: Twelve EEGs were acquired using both the standard routine scalp EEG system (XLTEK) and also with a QUASAR dry electrode prototype system at the same encounter, producing 24 recordings. The amount of time required to set up for each recording was measured. Subjects were surveyed as to how comfortable they perceived the QUASAR system to be. Three American Board of Clinical Neurophysiology (ABCN) certified clinical neurophysiologists reviewed the 24 EEG recordings using the web-based EEGnet system (blinded to the type of recording equipment) and rated the technical quality of each on a five-point scale. Results: The average time required to apply electrodes and prepare to record was 15.5 minutes for standard routine EEG and 4.8 minutes for the QUASAR system. Nine of 12 subjects rated the QUASAR system as either very comfortable (4 subjects) or somewhat comfortable (5 subjects). Three subjects rated the QUASAR system as mildly uncomfortable and no subjects rated the QUASAR system as very uncomfortable . Eleven of twelve subjects preferred to have the procedure performed with the QUASAR system over the standard system. The EEG technologist performing the recordings thought the QUASAR system was easy to use and preferred it over standard EEG. On a five point scale (5 best quality, 1- worst quality), the average rating by the three clinical neurophysiologists for the standard EEGs was 4.5 (SD 0.81) and for the QUASAR system was 3.3 (SD 0.83). The Fleiss kappa correlation for inter-rater agreement was 0.51, indicating moderate agreement. All neurophysiologists thought that all of the standard EEGs were interpretable. For the QUASAR EEGs, the one neurophysiologists thought all were interpretable, one thought 11 out of 12 interpretable, and one thought 10 out of 12 interpretable. The most common artifact reported for the standard EEGs was sweat artifact (4 EEGs) and for the QUASAR EEGs was electrode pops (all EEGs) and poor signal at a single electrode (5 EEGs). Conclusions: The QUASAR dry electrode EEG recording system offers quick and easy setup and is well tolerated by subjects. The technical quality of the recordings is less than standard EEG, although most recordings are interpretable. If improved a little, this system could be useful for a telemedicine approach to EEG recording within the VA Health System.