Impedance is the measure of electrical resistance to flow. In electrophysiology, we want the patient's electrical response to stimuli to flow through electrode wires to feed into the amplifier for graphing.
Before Checking Impedance
Clean the surface of the skin where necessary, and apply electrodes. Make sure to plug each electrode into its specified amplifier port.
From the test window, click on IMPED (short for Impedance).
Clicking this opens up a secondary window which depicts an image of the amplifier. The amplifier can be in one of two modes.
Indicates whether or not a connection is made.
FAIL = not connected
OK = connected
Indicates the quality of electrode connection using both a color scale & numerical readings in units of kOhm.
GREEN 0-5 = good to go
YELLOW 6-10 = alright, try pressing on the (skin) electrode connection
RED 11-15 = not ideal, try pressing on the (skin) electrode or reposition the DTL corneal electrode
Impedance greater than 15; remove and reapply the electrode
Each port of the physical amplifier is surrounded by a red LED ring. When IMPED is selected, the rings in need of electrode connections will illuminate.
Steady State Illumination = OK, Green
Slow Paced Blinking = OK, Yellow
Fast Paced Blinking = OK, Red
Dimly Lit = FAIL