Is there a risk involved with using NeuroSky's products for an extended period of time?

NeuroSky’s EEG headset does not send electricity or anything else into the brain or through the body. The headset simply listens, like a microphone, and is completely non-invasive. This is not a medical device. It is completely safe to use this device as often as you like.

IEC601 speaks to the safety of medical devices that depend on AC current. Since NeuroSky headsets are dependent on batteries (1.5 - 6 volts), the IEC601 standard does not apply.