| Skin conductance (which used to be known as the | | | | state to monitor has been emotional states. One of |
| galvanic skin response) is becoming one of the more | | | | the key uses for skin conductivity changes is in lie |
| common measuring tools for the autonomic nervous | | | | detector tests, since the stress level of a subject |
| system as well as stress levels. When external or | | | | can shift in very small ways when moving between |
| internal stimuli occur that change stress or attention | | | | truth and lies. Heart rate and blood pressure are |
| levels in any number of internal systems there is a | | | | impacted when stress levels rise but the shifts take |
| brief moment when the skin actually becomes a | | | | a bit of time to happen and by the time the changes |
| better conductor of electricity. This is also known as | | | | are noticeable the triggering stimulus is long past. The |
| the electrodermal response and this change in | | | | electrodermal response is very rapid and easy to |
| conductivity can be measured, allowing for a wide | | | | measure, making it a fast and reliable way to track |
| range of tests. | | | | changes in both emotions and stress levels. |
| The skin of a person in a state of relaxation does | | | | There are only a few places where it’s feasible |
| not conduct electricity well. This high resistance is | | | | to measure skin conductance response because of |
| usually measured as about 40 mV negative when | | | | the presence of eccrine sweat glands, which are |
| compared to tissue inside the body. Sweat gland | | | | highly responsive to emotional and other psychological |
| activity changes these properties by increasing skin | | | | stimuli. The palms of the hands and the soles of the |
| conductance and changing the balance of positive and | | | | feet have a high level of eccrine sweat glands and so |
| negative ions in the sweat. When a person gets | | | | electrodes are usually placed on the skin in these |
| more stressed there is a rise in the conductivity of | | | | areas. A tiny electrical charge is passed between the |
| skin and these changes tend to occur in waves. The | | | | electrodes and when the electrodermal response |
| term phasic is used to refer to these wavelike | | | | raises in conductivity level the change is measured |
| increases. | | | | and analyzed, allowing for a fast, accurate measure |
| One of the more difficult aspects of a patient’s | | | | of internal emotions and stress levels. |