The Science Behind Electrodermal Activity

February 20, 2023 | Raquel Paz Bergia | Biotechnology

EDA is a measuring tool of the electric signals of the body in response to sweat secretion. Most EDA devices have a Silver Chloride attachment to the skin that allows it to monitor the activity and transfer it to a recording machine. 

This article provides insight into the use of Electrodermal Activity, its functions, and its applicabilities. 

How does it work?

EDA signals measure the electoral signals radiating from the body. It utilizes technology that tracks ER-SCR, also known as Event-Related Skin Conductance Response. An increase in the levels of sweat for an individual is indicated by an increase in the ions present on the skin. The presence of many ions can increase the electric conductance of the skin.

Applicability: Seizures

An epileptic seizure is a transient occurrence of signs or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. A study conducted showed epileptic activity did the following: HR ↑⇒ SpO2 ↓⇒EDA ↑. A combination of EDA and ECG scans increases the recognition of neonatal seizures (a condition of recurring seizures in babies), and therefore it has a high chance of applying to children and adults. 

Overall, it can be understood that an EDA can track the way the brain behaves during seizures and epileptic episodes. A famous case of an epileptic seizure was Cameron Boyce, who died in 2020. He was diagnosed with epileptic seizures for many years, but he had no way of constantly tracking his brain activity. With these new technologies, when he underwent the seizure, his brain activity would have changed dramatically. The EDA monitor would have recorded this change and it would have been better understood by EMTs. 

Applicability: Neurological Trauma after Illness and Injury

Research conducted in 2015 showed that continuous EDA potentially opens a new avenue for autonomic function monitoring in neurocritical ill patients. The procedure they followed surrounded Cardiac Arrest Survivors who had experienced a lot of neurological damage. These patients were going through hypothermic therapy and they were being monitored with an EDA. This technology allowed the researchers to understand that the hypothermic therapy that they underwent increased their brain activity. Their normothermic brain activity was very low but increased exponentially when undergoing the therapy. This shows one of the many applications of an EDA for monitoring tracking post-illness or post-injury.

Another research study conducted in 2018 explained how EDAs can track pain. Specifically, electrodermal activity (EDA) can identify features of stress and anxiety induced by varying pain levels. A summary of a report conducted surrounding patients in vegetative states showed how people’s brains had a different activity based on the level of brain damage. Those with no damage had a high amount of brain activity, while those completely vegetative had little to no brain activity. Even though patients considered vegetative are not considered brain dead, it has been proven that they do not experience any electrodermal activity recorded with an EDA. EDA trackers can be used to regulate and track the progress of brain activity after the formation of the disorder.