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Concealed, Unobtrusive Ear-Centered EEG Acquisition: cEEGrids for Transparent EEG

View Article: PubMed Central - PubMed

ABSTRACT

Electroencephalography (EEG) is an important clinical tool and frequently used to study the brain-behavior relationship in humans noninvasively. Traditionally, EEG signals are recorded by positioning electrodes on the scalp and keeping them in place with glue, rubber bands, or elastic caps. This setup provides good coverage of the head, but is impractical for EEG acquisition in natural daily-life situations. Here, we propose the transparent EEG concept. Transparent EEG aims for motion tolerant, highly portable, unobtrusive, and near invisible data acquisition with minimum disturbance of a user's daily activities. In recent years several ear-centered EEG solutions that are compatible with the transparent EEG concept have been presented. We discuss work showing that miniature electrodes placed in and around the human ear are a feasible solution, as they are sensitive enough to pick up electrical signals stemming from various brain and non-brain sources. We also describe the cEEGrid flex-printed sensor array, which enables unobtrusive multi-channel EEG acquisition from around the ear. In a number of validation studies we found that the cEEGrid enables the recording of meaningful continuous EEG, event-related potentials and neural oscillations. Here, we explain the rationale underlying the cEEGrid ear-EEG solution, present possible use cases and identify open issues that need to be solved on the way toward transparent EEG.

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Single subject sleep EEG recording. Shown are three right ear cEEGrid EEG channels (blue), the horizontal electrooculogram (green), the electrocardioagram (red), and the head motion, as measured by the Smarting amplifier gyroscope (purple). Different characteristic sleep patterns are clearly visible, such as (A) theta activity, (B) k-complexes, and (C) slow wave sleep.
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Figure 7: Single subject sleep EEG recording. Shown are three right ear cEEGrid EEG channels (blue), the horizontal electrooculogram (green), the electrocardioagram (red), and the head motion, as measured by the Smarting amplifier gyroscope (purple). Different characteristic sleep patterns are clearly visible, such as (A) theta activity, (B) k-complexes, and (C) slow wave sleep.

Mentions: Figures 6, 7 show cEEGrid data recorded from one of the authors (SD) over a period of 9 h. One cEEGrid was attached to the right ear and the amplifier was attached to the neck with medical tape. Wireless data acquisition was performed with a smartphone placed at bedside. The Smarting amplifier allows for continuous monitoring of channel voltage and impedance data. This enabled us to monitor channel impedances over night. As can be seen in Figure 6, impedances dropped initially and then remained fairly constant throughout the night (with one exception at approximately 10 p.m., which was caused by physical interference of the cEEGrids with frame sides (from a pair of glasses). As illustrated in Figure 7, different EEG sleep features comprising theta activity, k-complexes and slow wave sleep could be captured with the cEEGrid. Compared to in-ear EEG (Zibrandtsen et al., 2016) the cEEGrid ear-EEG amplitudes are somewhat larger.


Concealed, Unobtrusive Ear-Centered EEG Acquisition: cEEGrids for Transparent EEG
Single subject sleep EEG recording. Shown are three right ear cEEGrid EEG channels (blue), the horizontal electrooculogram (green), the electrocardioagram (red), and the head motion, as measured by the Smarting amplifier gyroscope (purple). Different characteristic sleep patterns are clearly visible, such as (A) theta activity, (B) k-complexes, and (C) slow wave sleep.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5383730&req=5

Figure 7: Single subject sleep EEG recording. Shown are three right ear cEEGrid EEG channels (blue), the horizontal electrooculogram (green), the electrocardioagram (red), and the head motion, as measured by the Smarting amplifier gyroscope (purple). Different characteristic sleep patterns are clearly visible, such as (A) theta activity, (B) k-complexes, and (C) slow wave sleep.
Mentions: Figures 6, 7 show cEEGrid data recorded from one of the authors (SD) over a period of 9 h. One cEEGrid was attached to the right ear and the amplifier was attached to the neck with medical tape. Wireless data acquisition was performed with a smartphone placed at bedside. The Smarting amplifier allows for continuous monitoring of channel voltage and impedance data. This enabled us to monitor channel impedances over night. As can be seen in Figure 6, impedances dropped initially and then remained fairly constant throughout the night (with one exception at approximately 10 p.m., which was caused by physical interference of the cEEGrids with frame sides (from a pair of glasses). As illustrated in Figure 7, different EEG sleep features comprising theta activity, k-complexes and slow wave sleep could be captured with the cEEGrid. Compared to in-ear EEG (Zibrandtsen et al., 2016) the cEEGrid ear-EEG amplitudes are somewhat larger.

View Article: PubMed Central - PubMed

ABSTRACT

Electroencephalography (EEG) is an important clinical tool and frequently used to study the brain-behavior relationship in humans noninvasively. Traditionally, EEG signals are recorded by positioning electrodes on the scalp and keeping them in place with glue, rubber bands, or elastic caps. This setup provides good coverage of the head, but is impractical for EEG acquisition in natural daily-life situations. Here, we propose the transparent EEG concept. Transparent EEG aims for motion tolerant, highly portable, unobtrusive, and near invisible data acquisition with minimum disturbance of a user's daily activities. In recent years several ear-centered EEG solutions that are compatible with the transparent EEG concept have been presented. We discuss work showing that miniature electrodes placed in and around the human ear are a feasible solution, as they are sensitive enough to pick up electrical signals stemming from various brain and non-brain sources. We also describe the cEEGrid flex-printed sensor array, which enables unobtrusive multi-channel EEG acquisition from around the ear. In a number of validation studies we found that the cEEGrid enables the recording of meaningful continuous EEG, event-related potentials and neural oscillations. Here, we explain the rationale underlying the cEEGrid ear-EEG solution, present possible use cases and identify open issues that need to be solved on the way toward transparent EEG.

No MeSH data available.


Related in: MedlinePlus