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A tactile P300 brain-computer interface.

Brouwer AM, van Erp JB - Front Neurosci (2010)

Bottom Line: We did not find a difference in SWLDA classification performance between the different numbers of tactors.In a second set of experiments we reduced the stimulus onset asynchrony (SOA) by shortening the on- and/or off-time of the tactors.The SOA for an optimum performance as measured in our experiments turned out to be close to conventional SOAs of visual P300 BCIs.

View Article: PubMed Central - PubMed

Affiliation: TNO Human Factors Soesterberg, Netherlands. anne-marie.brouwer@tno.nl

ABSTRACT
In this study, we investigated a Brain-Computer Interface (BCI) based on EEG responses to vibro-tactile stimuli around the waist. P300 BCIs based on tactile stimuli have the advantage of not taxing the visual or auditory system and of being potentially unnoticeable to other people. A tactile BCI could be especially suitable for patients whose vision or eye movements are impaired. In Experiment 1, we investigated its feasibility and the effect of the number of equally spaced tactors. Whereas a large number of tactors is expected to enhance the P300 amplitude since the target will be less frequent, it could also negatively affect the P300 since it will be difficult to identify the target when tactor density increases. Participants were asked to attend to the vibrations of a target tactor, embedded within a stream of distracters. The number of tactors was two, four or six. We demonstrated the feasibility of a tactile P300 BCI. We did not find a difference in SWLDA classification performance between the different numbers of tactors. In a second set of experiments we reduced the stimulus onset asynchrony (SOA) by shortening the on- and/or off-time of the tactors. The SOA for an optimum performance as measured in our experiments turned out to be close to conventional SOAs of visual P300 BCIs.

No MeSH data available.


EEG averaged across participants and presented separately for targets (solid lines) and distracters (dashed lines) in the four conditions of Experiment 1. Only data from electrode Pz is presented.
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Figure 3: EEG averaged across participants and presented separately for targets (solid lines) and distracters (dashed lines) in the four conditions of Experiment 1. Only data from electrode Pz is presented.

Mentions: Figure 3 depicts the mean Pz EEG samples from 200 ms before stimulus onset until 800 ms after, for each condition, and separately for target and standard presentations (solid and dashed curves respectively). Pz is a location where the P300 is usually strongly displayed (e.g. Ravden and Polich, 1999; Srinivasan, 2007). Clearly, a P300 is present in all conditions, even in condition Two, although the amplitude seems to be smaller. The P300 occured later than 300 ms after the start of the stimulus. This corresponds to many P300 studies that report this as well (e.g. Ravden and Polich, 1999; Bledowski et al., 2004; Gerson et al., 2006).


A tactile P300 brain-computer interface.

Brouwer AM, van Erp JB - Front Neurosci (2010)

EEG averaged across participants and presented separately for targets (solid lines) and distracters (dashed lines) in the four conditions of Experiment 1. Only data from electrode Pz is presented.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2871714&req=5

Figure 3: EEG averaged across participants and presented separately for targets (solid lines) and distracters (dashed lines) in the four conditions of Experiment 1. Only data from electrode Pz is presented.
Mentions: Figure 3 depicts the mean Pz EEG samples from 200 ms before stimulus onset until 800 ms after, for each condition, and separately for target and standard presentations (solid and dashed curves respectively). Pz is a location where the P300 is usually strongly displayed (e.g. Ravden and Polich, 1999; Srinivasan, 2007). Clearly, a P300 is present in all conditions, even in condition Two, although the amplitude seems to be smaller. The P300 occured later than 300 ms after the start of the stimulus. This corresponds to many P300 studies that report this as well (e.g. Ravden and Polich, 1999; Bledowski et al., 2004; Gerson et al., 2006).

Bottom Line: We did not find a difference in SWLDA classification performance between the different numbers of tactors.In a second set of experiments we reduced the stimulus onset asynchrony (SOA) by shortening the on- and/or off-time of the tactors.The SOA for an optimum performance as measured in our experiments turned out to be close to conventional SOAs of visual P300 BCIs.

View Article: PubMed Central - PubMed

Affiliation: TNO Human Factors Soesterberg, Netherlands. anne-marie.brouwer@tno.nl

ABSTRACT
In this study, we investigated a Brain-Computer Interface (BCI) based on EEG responses to vibro-tactile stimuli around the waist. P300 BCIs based on tactile stimuli have the advantage of not taxing the visual or auditory system and of being potentially unnoticeable to other people. A tactile BCI could be especially suitable for patients whose vision or eye movements are impaired. In Experiment 1, we investigated its feasibility and the effect of the number of equally spaced tactors. Whereas a large number of tactors is expected to enhance the P300 amplitude since the target will be less frequent, it could also negatively affect the P300 since it will be difficult to identify the target when tactor density increases. Participants were asked to attend to the vibrations of a target tactor, embedded within a stream of distracters. The number of tactors was two, four or six. We demonstrated the feasibility of a tactile P300 BCI. We did not find a difference in SWLDA classification performance between the different numbers of tactors. In a second set of experiments we reduced the stimulus onset asynchrony (SOA) by shortening the on- and/or off-time of the tactors. The SOA for an optimum performance as measured in our experiments turned out to be close to conventional SOAs of visual P300 BCIs.

No MeSH data available.