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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.

No MeSH data available.


Grand average single channel result for an auditory attention paradigm as described in Bleichner et al. (2016). (A) cEEGrid channel pair that was used to compute data show in (B,C). (B) The grand average ERPs for attended tones (green) and unattended tones (red) showed clear differences in amplitude. Shaded gray areas indicate the standard error of the mean. (C) The effect size over time is given as Hedges' g (absolute) values.
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Figure 5: Grand average single channel result for an auditory attention paradigm as described in Bleichner et al. (2016). (A) cEEGrid channel pair that was used to compute data show in (B,C). (B) The grand average ERPs for attended tones (green) and unattended tones (red) showed clear differences in amplitude. Shaded gray areas indicate the standard error of the mean. (C) The effect size over time is given as Hedges' g (absolute) values.

Mentions: In the second study, cEEGrids and high-density cap-EEG data were compared in a spatial auditory attention paradigm (Bleichner et al., 2016). In this study, the participants had to attend to one of three simultaneously presented sound streams. The 3 s long sound streams originated from center, left and right locations and differed in a number of sound features as well as in the number of tones presented (3, 4, and 5, respectively). In this study, a replication of earlier multi-channel cap-EEG results (Choi et al., 2013) was possible with both high-density cap-EEG as well as cEEGrid ear-EEG. For both setups clear attention modulated ERPs in response to the attended sound stream were detected (Figure 5), and comparable single-trial classification accuracies at around 70% were achieved. Classification performance was not significantly different between cap-EEG and ear-EEG, which further suggests that the source configuration driving the condition effect in this paradigm was captured well enough with ear-EEG, resulting in no clear loss of information when compared to cap-EEG.


Concealed, Unobtrusive Ear-Centered EEG Acquisition: cEEGrids for Transparent EEG
Grand average single channel result for an auditory attention paradigm as described in Bleichner et al. (2016). (A) cEEGrid channel pair that was used to compute data show in (B,C). (B) The grand average ERPs for attended tones (green) and unattended tones (red) showed clear differences in amplitude. Shaded gray areas indicate the standard error of the mean. (C) The effect size over time is given as Hedges' g (absolute) values.
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Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383730&req=5

Figure 5: Grand average single channel result for an auditory attention paradigm as described in Bleichner et al. (2016). (A) cEEGrid channel pair that was used to compute data show in (B,C). (B) The grand average ERPs for attended tones (green) and unattended tones (red) showed clear differences in amplitude. Shaded gray areas indicate the standard error of the mean. (C) The effect size over time is given as Hedges' g (absolute) values.
Mentions: In the second study, cEEGrids and high-density cap-EEG data were compared in a spatial auditory attention paradigm (Bleichner et al., 2016). In this study, the participants had to attend to one of three simultaneously presented sound streams. The 3 s long sound streams originated from center, left and right locations and differed in a number of sound features as well as in the number of tones presented (3, 4, and 5, respectively). In this study, a replication of earlier multi-channel cap-EEG results (Choi et al., 2013) was possible with both high-density cap-EEG as well as cEEGrid ear-EEG. For both setups clear attention modulated ERPs in response to the attended sound stream were detected (Figure 5), and comparable single-trial classification accuracies at around 70% were achieved. Classification performance was not significantly different between cap-EEG and ear-EEG, which further suggests that the source configuration driving the condition effect in this paradigm was captured well enough with ear-EEG, resulting in no clear loss of information when compared to cap-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.

No MeSH data available.