Building an Ear-EEG System by Hacking a Commercial Neck Speaker and a Commercial EEG Amplifier to Record Brain Activity Beyond the Lab

Abstract

Electroencephalography (EEG) allows measuring human brain activity for scientific, diagnostic and therapeutic purposes. For scientific purposes, EEG is traditionally used to study the brain-behaviour relationship under well controlled laboratory conditions while the participant sits quietly in a room. Consequently, our knowledge regarding the brain-behaviour relationship was limited to human behaviour under constrained conditions. The development of mobile EEG hardware in the last years allows moving beyond the lab and studying brain activity in everyday life. Most EEG systems record from electrodes that are distributed over the head, kept in place with an elastic cap or net. For long term EEG recordings, to study natural behaviour in public, these systems are not optimal, as they are rather bulky and unpleasant to wear for longer periods. We argue for " transparent", ear-centered EEG systems instead. Transparent in the sense that both the person wearing the EEG system as well as the people interacting with that person are not disturbed by it. We describe here the integration of a commercially available research-grade mobile EEG amplifier and a commercially available neck speaker as a mounting system to be used in combination with ear electrodes (cEEGrid). This nEEGlace can be used for ear-EEG recordings in public over extended periods of time. The integrated microphone and the integrated speakers provide the possibility to play and record sound. This allows conducting experiments on auditory perception beyond the lab by both studying the brain responses to naturally occurring sounds as well as to experimental auditory stimuli. We describe the general design, present a working prototype, outline a number of use cases and discuss future improvements of the proposed design.

CameraEEG: Synchronized Recording of Video with Electroencephalogram data on an Android Application

“…The recording sessions of eyes closed and eyes open have been used to validate the performance of our application like in previous works [29], [30]. The peak in the spectra for eyes closed task in comparison to eyes open walking task concur with previous research and shows the proper recording of EEG by the application.…”

Recording brain activity with ear-EEG (cEEGrids)

“…For longer experiment, the amplifier can be taped to the cloths 17 or body 2 , stored in custom-made straps, or taped to headphones worn around the neck 1 or a neck protector commonly used for mountain biking. We have developed a prototype that combines a neckspeaker (for presenting auditory stimuli) with a mobile EEG amplifier and connectors to the cEEGrid 5 . We have used this approach successfully in a recent study (in preparation) in which we recorded ear-EEG for four hours while participants work in the office.…”

“…The cEEGrid consists of ten Ag/AgCl electrodes printed on flexprint material 3 . Combined with a miniaturized, mobile amplifier and a smartphone for data acquisition 4, 5 , cEEGrids can be used to collect ear-EEG for extended durations 1 .…”

“…Recently, we have complemented our transparent ear-EEG setup with new hardware and software developments. First, we have built the nEEGlace, a mobile EEG amplifier integrated into a neckspeaker 5 . The nEEGlace can be placed around the neck and the cEEGrids can be plugged in directly, making the setup faster and more comfortable for participants.…”

On the encoding of natural music in computational models and human brains

“…For instance, wireless EEGs were used for hyper-scanning two pianists performing a piano duet ( Zamm et al, 2020 ); and wireless systems were used to simultaneously collect physiological activity (e.g., electrocardiogram, facial muscle electromyogram, respiration, heart rates) from whole audiences (∼40 participants per concert) attending live string quintet performances ( Czepiel et al, 2021 ; Merrill et al, 2021 ; Tschacher et al, 2021 ). In particular, the feasibility of a wireless in-ear EEG system has drawn considerable attention ( Looney et al, 2014 ; Bleichner and Emkes, 2020 ; Nithya and Ramesh, 2020 ). A built-in EEG system in everyday devices (e.g., wireless in-ear headphones) might open a new possibility of collecting neural data from millions of people while they listen to their favorite music in their day-to-day lives.…”