EPOC outside the shield: comparing the performance of a consumer-grade EEG device in shielded and unshielded environments.

Low-cost, portable electroencephalography (EEG) devices have become commercially available in the last 10 years. One such system, Emotiv's EPOC, has been modified to allow event-related potential (ERP) research. Although the EPOC has been shown to provide data comparable to research-grade equipment and has been used in real-world settings, how EPOC performs without the electrical shielding, commonly used in research-grade laboratories, is yet to be systematically tested. In the current article we address this gap by conducting a simple EEG experiment in shielded and unshielded contexts. Participants (n = 13, mean age = 23.2 years, SD = 7.9) monitored the presentation of human versus wristwatch faces, responding whether the images were inverted or not. This method elicited the face-sensitive N170 ERP. In both shielded and unshielded contexts, the N170 amplitude was larger when participants viewed human faces and peaked later when a human face was inverted. More importantly, Bayesian analysis showed no difference in the N170 measured in the shielded and unshielded contexts. Further, the signal recorded in both contexts was highly correlated. The EPOC appears to reliably record EEG signals without a purpose-built electrically-shielded room.

Measuring the face-sensitive N170 with a gaming EEG system: A validation study.

BACKGROUND: The N170 is a "face-sensitive" event-related potential (ERP) that occurs at around 170ms over occipito-temporal brain regions. The N170's potential to provide insight into the neural processing of faces in certain populations (e.g., children and adults with cognitive impairments) is limited by its measurement in scientific laboratories that can appear threatening to some people. NEW METHOD: The advent of cheap, easy-to-use portable gaming EEG systems provides an opportunity to record EEG in new contexts and populations. This study tested the validity of the face-sensitive N170 ERP measured with an adapted commercial EEG system (the Emotiv EPOC) that is used at home by gamers. RESULTS: The N170 recorded through both the gaming EEG system and the research EEG system exhibited face-sensitivity, with larger mean amplitudes in response to the face stimuli than the non-face stimuli, and a delayed N170 peak in response to face inversion. COMPARISON WITH EXISTING METHOD: The EPOC system produced very similar N170 ERPs to a research-grade Neuroscan system, and was capable of recording face-sensitivity in the N170, validating its use as research tool in this arena. CONCLUSIONS: This opens new possibilities for measuring the face-sensitive N170 ERP in people who cannot travel to a traditional ERP laboratory (e.g., elderly people in care), who cannot tolerate laboratory conditions (e.g., people with autism), or who need to be tested in situ for practical or experimental reasons (e.g., children in schools).