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Brain–Computer Interfaces - Index of

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Toward Ubiquitous BCIs 359<br />

BCI Challenges<br />

Sensors<br />

Tasks<br />

Brain Effects<br />

Related Disciplines<br />

Electronics<br />

Signal Processing<br />

HCI<br />

Cognitive Neurosci.<br />

Communications<br />

Medicine<br />

Psychology<br />

Manufacturing<br />

Wearable Computing<br />

ExG Sensors<br />

Fig. 1 Key factors in BCI adoption and catalysts<br />

Key Factors<br />

Cost<br />

(financial, help, expertise, training,<br />

invasiveness, time, attention, fatigue)<br />

Throughput<br />

(alphabet, accuracy,<br />

speed, latency, effective throughput)<br />

Utility<br />

(support, flexibility, reliability, illiteracy)<br />

Integration<br />

(functional, distraction quotient,<br />

hybrid/combined BCIs, usability)<br />

Appearance<br />

(cosmesis, style, media, advertising)<br />

manufacturing, or wearable computing, improvements in these or other related<br />

disciplines will have a greater effect on BCI sensors.<br />

2.1 BCI Catalysts<br />

Sensors refer to devices used to monitor brain activity. Most BCIs rely on noninvasive<br />

electrical measures <strong>of</strong> brain activity [44] – that is, brainwaves recorded from the<br />

surface <strong>of</strong> the scalp. In ten years, most BCIs will probably still use scalp recorded<br />

EEGs, but this view is far from universal. There has been great attention in the<br />

BCI literature to BCIs based on other brain monitoring technologies such as fMRI,<br />

MEG, or fNIR [84]. These approaches are overrated for BCI applications. None <strong>of</strong><br />

these approaches has allowed an ITR comparable to EEG-based BCIs. fMRI and<br />

MEG require equipment that is not remotely portable and costs millions <strong>of</strong> dollars.<br />

fNIR is a bit more promising, since it is less expensive and more portable. Similarly,<br />

there has been more work describing invasive BCI systems recently [16, 31, 34, 38,<br />

71] and corresponding enthusiasm for providing much greater benefits to patients<br />

(see Chapters “Intracortical BCIs: A Brief History <strong>of</strong> Neural Timing”, BCIs Based<br />

on Signals from Between the Brain and Skull”, and “A simple, Spectral–Change<br />

Based, Electrocorticographic Brain–Computer Interface” in this book).<br />

How can BCI sensors be improved? Modern laboratory EEG sensors have several<br />

problems. An expert must rub the scalp to clean the skin and remove dead<br />

skin cells, precisely position the electrodes, squirt electrode gel to get a good<br />

S<strong>of</strong>tware and Hardware

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