Electrodermal activity measured by the Moodmetric ring

Electrodermal activity

With any sympathetic nervous system activation, skin reacts and becomes a better conductor of electricity. This can result from emotional, cognitive or other psychological origin. The phenomenon is known as electrodermal activity (EDA) and it is widely adopted in psychological research (1). Other commonly used terms for this phenomenon are skin conductance response and galvanic skin response.

EDA is generated by the activity of the sweat glands.  Moodmetric measures the palmar skin on your finger. The palmar skin is the recommended EDA measurement location, since it has the highest eccrine sweat gland density (2). You can measure EDA elsewhere as well but the reliability is not as high or as easily achieved.

The unconscious actions of the human body are regulated by the autonomic nervous system. It consists of the sympathetic part and the parasympathetic part. The parasympathetic part controls the body’s rest-and-digest functions and the sympathetic part controls the fight-or-flight reactions. With EDA, we can examine the latter.

The sweat glands are exclusively innervated by the sympathetic nervous system. This makes EDA an ideal measure for sympathetic activation (2). Electrodermal activity correlates to general cognitive and emotional intensity, and high responses are caused by e.e. stress, enthusiasm, anxiety, joy, anger (1, 3).

Mobile EDA devices have been used by scientists for some time (2, 4). The Moodmetric ring is an unobtrusive option to follow EDA responses real-time and in long term.

Signal accuracy

The signal accuracy has been proven in a study of 24 people by the Finnish Institute of Occupational Health by J. Torniainen et al.. The accuracy against a laboratory grade reference was found to be 83 %. They conclude:

“Clearly the ring sensor can be used to measure a valid EDA signal as indicated by the similarity of both event-related responses and the calculated features. The accuracy of the Moodmetric EDA Ring is adequate for psychological and physiological research when weighted against the advantage of conducting ecologically valid experiments outside laboratory conditions.”

The results were accepted for publication in the 2015 conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2015, August 25-29).

The Moodmetric measurement has also been proven to be accurate by THe University of Tampere, Finland. The correlation with the reference equipment Nexus-10-MK II was good. Comparison details in charts below.

With skin conductance level (SCL) we refer here to raw measured skin conductance without any filtering. The figures below show the comparison of the two devices. 

References

1 Mendes, W.B. (2009). Assessing the autonomic nervous system. In: Harmon-Jones   E. ja Beer J.S. Methods in social neuroscience. New York: Guilford Press. p. 118-147.

2 Setz C., Arnrich B., Schumm J. and La R. (2010) Discriminating Stress From Cognitive Load Using a Wearable EDA Device. IEEE Trans. Inf. Technol. Biomed. 14(2). p. 410-417.

3 Nikula R. (1991) Psychological correlates of nonspecific skin conductance responses. Psychophysiology. 28(1). p.86-90.

4 Poh M.Z, Swenson N.C. and Picard R.W. (2010) A Wearable Sensor for Unobtrusive, Long-Term Assessment of Electrodermal Activity. IEEE Trans. Biomed. Eng. 57(4). p. 1243-1252.

 

 

Summer reading

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Things seem to be so much brighter without the everyday  lurch in the stomach when the alarm clock goes off. Morning coffee without hurry, sun and laziness ahead for the day.. Yet this perfect battery charging is only allowed in limited doses for the most of us.

The work, studies, school – they will begin. La rentrée – the return, has an effect on each one of us. But how big and what kind?

The children get to buy new things for school and meet again with the friends. Most of them really enjoy the start of their duties. The adults mostly seem to stress about it all: the autumn hits with dozens of things and tasks, the work being only part of the palette.

Would you like to measure the effect? To know exactly how much does your stress and anxiety increase when starting the engines again? The summer reading (not meaning the pick of holiday novels) has been low, your mind has been calm.

The emotional level reading is about get higher during the autumn. For many people the change is not significant, but the numbers might increase alarmingly.

The Moodmetric smart ring measures your stress levels from the changes in the skin conductance. Find out more from our blog, and inquire about pre-ordering at [email protected].

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What is moodtech? – Science behind Moodmetric

Moodmetric measures the electrodermal activity (EDA) of the skin, which is widely adopted in psychological research 1. EDA is generated by activity of the sweat glands.  Moodmetric measures the palmar skin on your finger. The palmar skin is the recommended EDA measurement location, since it has the highest sweat gland density2.

The unconscious actions of the human body are regulated by the autonomic nervous system. It consists of the sympathetic part and the parasympathetic part. The parasympathetic part controls the body’s rest-and-digest functions and the sympathetic part controls fight-or-flight reactions. When bodily functions are not of interest and the emotional side is, sympathetic nervous system is your choice.

The sweat glands are exclusively innervated by the sympathetic nervous system. This makes EDA an ideal measure for sympathetic activation.2 Electrodermal activity correlates to general emotional intensity, negative emotion, concern, and anxiety. 1, 3 These emotions cause almost similar electrodermal responses, which makes them very hard to differentiate. However, Moodmetric will tell you if certain parts of your day have brought up emotions or not. Inversely, Moodmetric tells you weather you are calm or not. This is particularly useful during your mindfulness, meditation and other calming exercises.

Mobile EDA devices have been used by scientists for some time2, 4, and now we bring this technology within everyone´s reach.

Signal accuracy

The signal accuracy has been proven in a study of 24 people by the Finnish Institute of Occupational Health by J. Torniainen et al.. The accuracy against a laboratory grade reference was found to be 83 %. They conclude:

“Clearly the ring sensor can be used to measure a valid EDA signal as indicated by the similarity of both event-related responses and the calculated features. The accuracy of the Moodmetric EDA Ring is adequate for psychological and physiological research when weighted against the advantage of conducting ecologically valid experiments outside laboratory conditions.”

The results have been accepted for publication in the 2015 conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2015, August 25-29).

Our measurement has been proven to be accurate also by University of Tampere, Finland. The correlation with the reference equipment Nexus-10-MK II was good. Comparison details in charts below.

image1 image2 image3 image4

1 Mendes, W.B. (2009). Assessing the autonomic nervous system. In: Harmon-Jones   E. ja Beer J.S. Methods in social neuroscience. New York: Guilford Press. p. 118-147.

2 Setz C., Arnrich B., Schumm J. and La R. (2010) Discriminating Stress From Cognitive Load Using a Wearable EDA Device. IEEE Trans. Inf. Technol. Biomed. 14(2). p. 410-417.

3 Nikula R. (1991) Psychological correlates of nonspecific skin conductance responses. Psychophysiology. 28(1). p.86-90.

4 Poh M.Z, Swenson N.C. and Picard R.W. (2010) A Wearable Sensor for Unobtrusive, Long-Term Assessment of Electrodermal Activity. IEEE Trans. Biomed. Eng. 57(4). p. 1243-1252.

 

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