Biosignals: Measurement and analysis

with applications in psychology Nadica Miljković, Olga Dubljević, Bojana Bjegojević, and Nikola Milosavljević

University of Belgrade – School of Electrical Engineering

and

Department of Psychology and Laboratory for research of individual differences, Faculty

of Philosophy, University of Belgrade

26th Empirical Studies in Psychology, Symposium “Emotion: Elicitation and physiological assessment”, October 15-18, 2020

I am

• Nadica Miljković

• Associate Professor at the University of Belgrade – School of Electrical Engineering

• My main research interest is biomedical engineering – I am measuring and analyzing biosignals

a lot!

• I have >10 years long experience in Academia and >6 years in industry

• For more than a year I have successful collaboration with LIRA members – This presentation and symposium are

result of that collaboration.

– I’ll try to answer to “What have we done and what can we do together?”

Photograph is taken by Assist. Prof. Miodrag Tasić, PhD at the University of

Belgrade – School of Electrical Engineering.

What to expect?

• Presentation of multi-, inter-, and cross-disciplinary research: – Biosignals: definition

– Overview of biosignal applications in psychology

– Opportunities, but also disadvantages and limitations

– Message to take home or to laboratory

• EIP Symposium on “Biosignals: Measurement and analysis with

applications in psychology” – Nadica Miljković et al., “Biosignals: Measurement and analysis with

applications in psychology”

– Marija Kušić et al., “Imaginal provocation test as a way to induce emotions in the labs”

– Bojana Bjegojević et al., “In pursuit of objectivity: Physiological measures as a means of emotion induction procedure validation”

– Nenad B. Popović et al., “Effects of violent stimulus on gastric activity: Electrogastrography-based case study”

– Milan Antić, et al., “CardioPRINT: Individual features hidden in electrocardiogram and impedance-cardiogram”

BIOSIGNALS

Signal vs. biosignal

• “Generally speaking, Biosignals refer to signals recorded from the human body. They can be either electrical (e.g. Electrocardiogram (ECG), Electroencephalogram(EEG), Electromyogram (EMG), etc.) or non-electrical (e.g. breathing, movements, etc.)”, Naït-Ali, Amine, ed. Advanced biosignal processing. Springer Science & Business Media, 2009.

• It usually refers to electrical biosignals i.e., electrophysiological signals.

– EMG, ECG, EEG, EGG, ENG, EHG … sound familiar?

• How biosignals differ from other signals:

– “human body” from the definition – very complex to analyze

– high sensitivity to artifacts (noise), since it has a small amplitude and it can be affected by power hum, cell phone, movement, contact, other biosignals …

What is biosignal and where is noise?

Originally, EMG (electromyography) signal with ECG (electrocardiography) noise was recorded from Pectoralis

muscle. Aftermath, we could extract heart beats with EMG artifact.

Image is taken from N. Miljković, Digital biosignal processing with R, satRday Conference in Belgrade,R

Consortium, Belgrade, Serbia,October 27,2018, [CD-ROM, Online], https://github.com/NadicaSm/satRday-

Belgrade-2018 Assessed December 5, 2019, and https://belgrade2018.satrdays.org/,Assessed December 5, 2019.

Biosignals

EEG

ECG

EMG

EGG

Special thanks to my PhD student Nenad B. Popović for preparing this slide.

BIOSIGNALS &

EMOTION ASSESSMENT

I am

• Olga Dubljević

• MSc of Psychology and

member of LIRA

• I will give an overview of

what we can measure

with BIOPAC in terms of

Psychological research and

why

Photo: Emotion Recognition by fotologic; Flickr https://www.flickr.com/photos/fotologic/23742687222/; CC BY 2.0 Generic.

How engineers see emotion recognition?

Photo: Emotion Recognition by fotologic; Flickr https://www.flickr.com/photos/fotologic/23742687222/; CC BY 2.0 Generic.

How psychologists see emotion recognition?

Photo: Emotion Recognition by fotologic; Flickr https://www.flickr.com/photos/fotologic/23742687222/; CC BY 2.0 Generic.

How psychologists see emotion recognition?

Image: with kind permission from iMotions, https://publish.imotions.com/wp-content/uploads/2019/11/Sympathetic-parasympathetic-nervous-systems.png

Why we work together?

• Measuring and analyzing biosignals can be used for quantitative assessment of person’s state.

• Possible applications:

– Emotion detection

– Monitoring behavior

– Studying individual differences

– Arousal assessment

– Biofeedback

– …

Engineers know how to use

measurement hardware and

software, and what to do with the

signal.

Psychologists know how to create

protocols, provoke emotions, and

interpret results.

SAMPLE

MEASURES

Electrodermal

Activity – EDA ___________________

Photographs are taken at the Laboratory for research of individual differences, Faculty of Philosophy, University of Belgrade

What can influence EDA and

its parameters?

Physical activity

Psychological activity

BIOPAC: dry and wet electrodes

Very interesting study

• They measured physiological reactions to the loss of data. How sadness influences EDA? – Reference: Lost data research report: Astrid

Carolus et al., “Lost data: Research report”, Kaspersky Lab, Julius-Macimilians-University Wuerzburg, Germany, https://media.kaspersky.com/pdf/Lost_Data_Research_Report_Final.pdf, conducted in 2017, Assessed on December 6, 2019.

• They also measured facial thermal activity.

Photo: Thermography by highlander411; Flickr https://www.flickr.com/photos/highlander411/1764226014/; CC BY 2.0 Generic.

Impedance Cardiography (ICG)

Electrocardiogram (ECG or EKG)

Electrogastrogram (EGG)

Electromyography (EMG)

LETS SEE A DEMO

Photo: Angry by Clemens v. Vogelsang; Flickr https://www.flickr.com/photos/vauvau/3466024918; CC BY 2.0 Generic.

Takeaway

• Biosignals are complex

• Many factors influence them – For example, H-reflex amplitude can be affected by the ambient light; ambient sounds; head

orientation; body position; leg movements: caffeine and nicotine uptake; body temperature; pressure over nerve during stimulation … Challenging indeed!

• You should always be careful when designing protocols and performing studies.

• Qualitative and quantitative procedures

• Experience helps a lot (quote: https://twitter.com/SpringerNature/status/1196367469050507264).

person

Acknowledgement

We are very grateful to all LIRA members, especially to Senior Research Associate Ljiljana Lazarević, Assistant Professor Danka Purić, Associate Professor Iris Žeželj, and Professor Goran Knežević.

All pictures if not stated otherwise are taken at the Laboratory for research of individual differences, Faculty of Philosophy, University of Belgrade or at the School of Electrical Engineering, University of Belgrade.

Special thanks to Denis Ćoragić who agreed to participate as a model subject for this presentation.