Measurement of neural signals from inexpensive, wireless and dry EEG systems

Abstract

Electroencephalography (EEG) is challenged by high cost, immobility of equipment and the use of inconvenient conductive gels. We compared EEG recordings obtained from three systems that are inexpensive, wireless, and/or dry (no gel), against recordings made with a traditional, research-grade EEG system, in order to investigate the ability of these 'non-traditional' systems to produce recordings of comparable quality to a research-grade system. The systems compared were: Emotiv EPOC (inexpensive and wireless), B-Alert (wireless), g.Sahara (dry) and g.HIamp (research-grade). We compared the ability of the systems to demonstrate five well-studied neural phenomena: (1) enhanced alpha activity with eyes closed versus open; (2) visual steady-state response (VSSR); (3) mismatch negativity; (4) P300; and (5) event-related desynchronization/synchronization. All systems measured significant alpha augmentation with eye closure, and were able to measure VSSRs (although these were smaller with g.Sahara). The B-Alert and g.Sahara were able to measure the three time-locked phenomena equivalently to the g.HIamp. The Emotiv EPOC did not have suitably located electrodes for two of the tasks and synchronization considerations meant that data from the time-locked tasks were not assessed. The results show that inexpensive, wireless, or dry systems may be suitable for experimental studies using EEG, depending on the research paradigm, and within the constraints imposed by their limited electrode placement and number.

Automated seizure detection systems and their effectiveness for each type of seizure

“…A group used four electrodes installed in a 20 cm area and demonstrated that this is feasible and comparable to a 10-20 EEG system [44]. The Emotiv EPOC is a low-cost wireless system with 14 electrodes and a battery life of 12 hours enabling the device to be worn during the day [50,51]. The B-Alert is a wireless EEG head unit with 21 channels (20 electrodes), in which the data is transmitted to the receiver [50].…”

“…The Emotiv EPOC is a low-cost wireless system with 14 electrodes and a battery life of 12 hours enabling the device to be worn during the day [50,51]. The B-Alert is a wireless EEG head unit with 21 channels (20 electrodes), in which the data is transmitted to the receiver [50]. These two systems were compared and B-Alert (in two different versions) was the most similar to a research-grade system and it detected all of the EEG expected features [50,51].…”

“…The B-Alert is a wireless EEG head unit with 21 channels (20 electrodes), in which the data is transmitted to the receiver [50]. These two systems were compared and B-Alert (in two different versions) was the most similar to a research-grade system and it detected all of the EEG expected features [50,51]. Another wireless system was developed for ambulances and emergency departments with a short preparation time because it is a cap with six channels [52].…”

Brain Computer Interface applications and classification techniques

“…The ERD occurs in the 1 s that precedes a response in both the mu (8-14 Hz) and beta bands (14-25 Hz). In contrast, the ERS is only shown in the beta band and is strongest in the 1-2 s period after a response [11].…”

Impedance analysis of ZnO nanowire coated dry EEG electrodes

“…In recent years, different types of dry electrodes, such as polymer foam electrode, solid-gel electrode, textile electrode, pin-shaped metallic electrode have been developed. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] To evaluate the performance of these electrodes, comparing the spontaneous EEG signals (e.g., the alpha wave) or the evoked potential acquired by the dry electrodes and conventional Ag/AgCl electrodes qualitatively or quantitatively is a common approach. [2][3][4][11][12][13] However, the signal quality is not only affected by the electrode itself, but also the acquisition components of the EEG system.…”