What Can Electrodermal Activity Measurements Tell You?
Electricity is everywhere. It’s in the air, it’s deep inside the earth, and it’s even in our bodies. Our cells conduct electrical currents, and electricity is needed for the body and the brain to communicate.
The skin also conducts electricity in the body. Thanks to scientific advancements, variations in the electrical characteristics of the skin can be measured. This is called electrodermal activity (EDA).
Also known as skin conductance, electrodermal response (EDR), psychogalvanic reflex (PGR), and galvanic skin response (GSR), measurements of electrodermal activity may tell us a variety of things about the state of the body, including the following.
Perhaps the most well-known application of electrodermal activity testing is determining emotional states of the mind. Like other applications of EDA, emotional reactions can be observed from the body’s response to a stimulus. A word, image, sound, or other stimulus can illicit an emotional response, which manifests as a change in the electrical conductivity of the skin.
Studies have confirmed that electrodermal activity does indeed correlate to emotional states. For example, one study conducted in the 1980s found that subjects who had high scores on an anxiety test had lower skin conductance levels and lower skin conductance response amplitudes compared to subjects with low anxiety.1 Similarly, a 2018 study found that skin conductance levels were lower for depressive subjects compared non-depressed subjects.2
Interestingly, EDA responses also correlate to introversion and extroversion. A 1991 study found that introverts react more strongly to negative mood induction, while introverts react more strongly to positive mood induction.3 Additionally, electrodermal activity may help detect aggressive and violent behavior tendencies when combined with heart-rate monitoring.4
In addition to emotions, another cognitive state that electrodermal activity can help determine is attention. For instance, recent research shows that the performance of mentally demanding tasks increases electrodermal response.5 Previous research has also found that tonic skin conductance, one of the two components of electrodermal response, changes “mainly as a function of cognitive activity.”6
It’s clear from these and other studies that electrodermal activity varies depending on the components and parts of the brain that are being engaged. We can also observe from these measurements that high-stress individuals may have more difficulty accomplishing complex cognitive tasks that are also highly stressful.
Depth of hypnotic trance
Establishing the depth of a trance helps hypnotists improve experience and outcomes in therapeutic and experimental settings. Although a hypnotist can ask a subject questions to help determine trance depth and level of suggestibility, electrodermal activity measurements provide more immediate, accurate feedback.
One study suggests that during the induction stage of hypnosis, highly hypnotizable people experience a shift to right-sided electrodermal dominance, while low hypnotizable people experience a left-sided shift.7 Another study conducted in the 1960s found a high positive correlation between basal skin resistance and the depth of hypnotic states.8
These and other similar studies show that electrodermal activity can not only be useful in practice but also for better understanding what’s happening in the brain during hypnotic states. For example, the correlation between skin conductance and hypnotic states may explain why hypnosis is effective for treating disorders strongly related to the sympathetic nervous system.9
If you’ve lived with someone who is prone to seizures, you know that they can be difficult to detect and respond to in a timely manner. Electrodermal activity, however, can be used to help accurately detect seizures. Better yet, devices that measure electrodermal activity are more practical and cost-efficient than electroencephalography (EEG) and video monitoring.
Research has shown that accelerometry with EDA measurement greatly improve the accuracy of seizure detection.10 Wristbands such as the Embrace2 device incorporate these two measurements along with an app that notifies loved ones when help is needed. These devices can be invaluable for the roughly 50 million people worldwide who suffer from epilepsy.11
One area where electrodermal activity is being utilized more and more frequently is physical performance. EDA measurements give athletes, coaches, and trainers insights into the psychophysiological aspects of performance. This knowledge can then be used to make an athlete more successful in their sport.
In the case of physical performance, electrodermal activity monitoring is often combined with electromyography (EMG) and electrocardiography (ECG). Together, these monitoring methods can lead to improved psychological interventions, such as relaxation and attentional strategies. In turn, these interventions can improve motor functions and make athletes more capable of achieving peak performance.12
Electrodermal activity monitoring can also provide an athlete with information related to their stress load. This information can help the athlete better understand the sources of their stress and how that stress impacts their performance.13
Vulnerability to schizophrenia
It’s estimated that more than 50 million people worldwide suffer from schizophrenia. The majority of those who don’t receive treatment are not aware that they have this disorder. Electrodermal activity can assist in properly diagnosing these individuals.
Research indicates that schizophrenics have an over-aroused electrodermal response, including elevated skin conductance level and frequent non-specific skin conductance responses.14 A hyperactive responder pattern has also been found to correlate to poor outcomes of acute schizophrenic episodes, as well as increased risk of schizophrenia in children.15
Did you know that electrodermal activity measurements are a key component of polygraph machines, better known as lie detectors? Combining EDA with blood pressure, pulse, and respiration monitoring, the polygraph is a powerful tool for detecting deception.
Research shows that electrodermal activity increases when the behavior inhibition system (BIS) is activated.16 It is believed that the BIS responds to threats and punishments by means of avoidance behavior. Thus, an increase in electrodermal activity may indicate that the subject is trying to deceive in order to avoid punishment.
Studies have shown that EDA combined with cardiovascular and respiratory measures are effective at determining whether a person is telling the truth or lying.17 A study in 1978, for example, revealed significant discrimination between guilty and innocent prisoners in a mock crime.18
Biological coherence to wellness options
People often choose supplements and other wellness options based on limited information. But electrodermal activity measurements can help you determine which products and options your body prefers, or your biological coherence. This takes the guesswork out of wellness decisions because options are presented to the body and the body responds objectively.
Similar to lie detector testing, biological coherence is determined by first establishing a baseline galvanic skin response measurement. Then, the changes in galvanic skin response are measured as digital signatures representing biomarkers in the body and external factors are introduced. Finally, digital signatures of wellness products and other options can be introduced to the body and we can see which ones are the most biologically coherent in relation to the significant biomarker responses. This is how a basic ZYTO biocommunication scan, or bioscan, works.
ZYTO scanning builds on advancements in electrodermal screening to provide a picture of wellness. The individualized, objective information in ZYTO reports helps wellness professionals and their clients make better wellness decisions.
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