Skin Conductance
Definition:
A galvanic skin response (GSR) sensor is used to measure the electrical conductance of the skin, which varies with its moisture level.
Skin conductance level (SCL):
typically 2-20 µS
Skin conductance response (SCR):
typically 0.1-1.0 µS
Frequency of non-specific skin conductance response:
1-3 per minute
Typical Applications:
Physiologically, GSR quantifies sweat gland activity and changes in the sympathetic nervous system. Measured from the palm or fingertips, there are changes in relative conductance of a small electrical current between the electrodes. The activity of sweat glands in response to sympathetic nervous stimulation (increased sympathetic activation) results in an increase in conductance. There is a relationship between sympathetic activity and emotional arousal, although one cannot identify the specific emotion being elicited.
Typical BioRadio Configuration:
- For SCL measurements:
- Coupling: DC
- Range: ±2 V
- Gain: 158.7258
- Offset: -0.1533
- Filter: 4th order, lowpass, Butterworth with lower cutoff of 0.05 Hz
- For SCR measurements:
- Coupling: AC
- Range: ±100 mV
- Gain: 0.1587258
- Offset: -0.1533
- Filter: 4th order, Bandpass, Butterworth with upper cutoff of 1 Hz and a lower cutoff of 0.05 Hz
Typical Setup:
Step 1:
Clean location with an alcohol wipeStep 2:
Wait until the location is dry before placing the sensor.
Common Questions:
Q: Why are the conductance readings varying so rapidly?
A:
Skin conductance varies with its moisture level—the presence of sweat could result in altered data. See Typical Setup for tips about how to optimize the GSR signal.