I think the author means single channel and not single electrode. At least the picture suggests that there are three electrodes (one to the skull two white ear clips for ground&#x2F;reference). For bipolar electrodes you need three:  channel, ground and reference. For unipolar electrodes, just two.<p>You can remove artifacts like eye and muscle movements with prepossessing, not as well as with electrodes, but still.<p>I&#x27;m more worried about electrode connections and electrode quality in these amateur EEG applications. You also want high quality active electrodes if you take EEG outside laboratory. I&#x27;m also skeptical about these dry skin electrodes (no alcohol scrubbing and conductive paste).  NeuroSky devices are surprisingly cheap. I would be very interested to know how well they work in practice.