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EEG sensors are sensitive
enough to detect small
electrical signals on the
cortex. Occasionally, sensors
may lie directly atop a blood
vessel. When this occurs,
sensors may detect the
subject’s pulse. Slightly move
the sensors to reduce pulse
artifacts.
Power lines operate between
50 and 60 Hz. Unsecure
power sources may leak
electromagnetic frequencies.
Because EEG records
frequencies from 1hz to about
40hz, power line noise may
negatively impact recordings
on all channels. This is
especially the case when
connection between sensor
and scalp is poor.
UnderstandingReadings
PulseArtifact
MildPowerLineArtifact
To avoid power line artifacts,
have subjects sitting at
least 3 feet from power
cords, plugged-in devices,
and lighting or overhead
uorescent lights. The
Quick-20r shields the sensors
from environmental noise,
but issues can still occur
with poor skin contact. If
power line artifacts appear
on all channels, lightly wet A1
Reference Drypad Ear Sensor.
StrongPowerLineArtifact
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