The Moodmetric smart ring for preventive stress management is an invention of a Finnish company Vigofere Oy. The inventor Henry Rimminen (Ph.D.) has a solid background in sensor technology and physiological measurements. He came up with the idea of incorporating the electrodermal activity (EDA) measurement into a ring in 2011. The phenomenon measured is also known as skin conductance (SC) and galvanic skin response (GSR). The measurement signal accuracy is comparable to laboratory devices and the research by the Finnish Institute of Occupational Health (Torniainen et al. 2015) has found the device valid for field research.

Electrodermal activity (EDA) is one of the most studied psychophysiological markers of the functioning of the autonomous nervous system and it has been applied in psyhcophysiological research for over 100 years (Boucsein 2012). EDA is an indicator of the sympathetic activity of the autonomous nervous system that is associated with emotion, cognition, and affection (e.g. Critchley 2002).

The skin becomes a better conductor of electricity when the eccrine sweat glands process sweat to skin surface. Eccrine glands are innervated by the sympathetic nervous system and are part of ​the fight or flight response​ system. The palmar site of the skin or sole provide the best measurement points due the great intensity of the eccrine sweat glands. (e.g. Boucsein 2012.)

The Moodmetric index is calculated by an algorithm developed by Vigofere Oy. It describes arousal of a person on a scale of 1 to 100. High arousal can be both positive and negative, e.g. being enthusiastic or in anguish. The sympathetic nervous system is very active. When the index numbers are low, the parasympathetic nervous system works and enhances recovery. The Moodmetric index daily average number is an indicator of the balance of the autonomous nervous system. This balance is important when the target is to prevent chronic stress. Clinical studies starting in spring 2018 aim to further validate research based information supporting these hypothesis.

There are little ambulatory measurement applications for stress available. Long term measurement is needed when a) wanting to understand is high stress load momentary or going on for weeks or months indicating chronic stress b) motivating a person to efficient stress management with real time feedback. The Moodmetric smart ring fits these purposes well. Read more about physiological measurement of stress in our series of five articles:

Diseases relating to the functionality of the autonomous nervous system may affect electrodermal activity. Patients with hyper- or hypothyroidism have been recorded with unusual EDA measurements (e.g. Dolu et al. 1997; Dolu et al. 1999). Within a variety of anxiety disorders (e.g. panic disorder and posttraumatic stress disorder), increased electrodermal activity and reactivity has been observed (Braune et al., 1994; Hoehn et al., 1997, Lader & Wing, 1964; Blechert et al., 2007). However, in depression electrodermal activity is often reduced (Argyle, 1991; Ward et al., 1983). Electrodermal activity measurement has not been largely applied in clinical research until now. It has been limited to laboratory environment before the entry of wearable devices.

Download PDF with references here
The Moodmetric cloud service

From the mobile app it is possible to download the data to the Moodmetric cloud. The cloud enables long term remote monitoring, and uploading the data from the cloud to further analysis in csv or excel format.

Software developer KIT

The Moodmetric SDK allows everyone to develop their own application using the Moodmetric measurement data. To ensure operation of 3rd party applications in any mobile platform or computer operating system, Moodmetric provides interface documentation directly to the ring. The platform running the 3rd party application must be Bluetooth smart ready. With the SDK you can access e.g. the Instant Indicator and the Moodmetric Index.

The Instant indicator

The Instant indicator is a fast indicator on how the person reacts to different stimuli. These can be what you see, hear, smell or sense by touch at a certain moment. The response can be seen as an upward spike, which starts approximately after 1.5 seconds after the stimulus and peaks approximately after 2.5-3.0 seconds

The Moodmetric Index

The Moodmetric Index / the MM level is a continuous indicator on the wearer´s stress level on a scale of 1 too 100. The index is resistant to motional artefacts and comparable among different users.

Access raw data with the Windows PC logging software

The Moodmetric ring does not store raw data. It can only be viewed with live streaming. For this purpose we have developed a the Windows PC logging software that works with a BLE dongle.

Contact [email protected] for more information

Frequently asked questions

Read more

A short review and primer on electrodermal activity in human computer interaction applications (Benjamin Ultan Cowley, Jari Torniainen)

Past Moodmetric research projects with Universities


University cooperation and research projects: Jari Jussila –  [email protected] +358 40 717 8345