Introduction

This training is intended for researchers and students who want to learn how to measure fEMG with the BIOPAC system.  

This page can be used in three ways: 

• As a guide for trainers delivering fEMG training 

• As a digital handout for trainees 

• As reference material when running an fEMG study with BIOPAC 

This training assumes all equipment is already correctly set up and connected. If you need assistance with hardware setup, please contact labsupport@fsw.leidenuniv.nl.  

Estimated duration: ~ 30 minutes 

Learning Goals

By the end of this training, you will be able to: 

• Have basic knowledge about BIOPAC 

• Know what fEMG is 

• Understand how the BIOPAC fEMG equipment is set up and how to use it safely 

• Prepare a participant and apply 5 fEMG electrodes correctly 

• Use AcqKnowledge to record fEMG data 

• Obtain good data 

Not included in this training: 

• Experimental design 

• Physiological data analysis 

Materials

The following is required for this training: 

• BIOPAC equipment including an EMG module (EMG100C with EL254S and EL254 leads or EMG2R with  BN-EL15-Lead3 and BN-EL15-Lead2 leads and EL654 reusable snap electrodes). The BIOPAC should be connected to a PC on which AcqKnowledge is installed. 
• EMG reusable electrode
• Electrode sticker rings (13x5 mm)
• Electrode gel (Signa)
• Plastic syringe with curved tip
• Scrub gel (NuPrep)
• Non-woven swabs or Q-tips
• Gloves
• Incidin OxyWipe

Step-by-Step Training Plan

Introduction to fEMG, BIOPAC and AcqKnowledge

1. Read the Introduction section of the fMEG page to obtain a basic understanding of fEMG. 
2. On the BIOPAC page read the following sections: 
   • The Introduction section 
   • The Safety section 
   • Read the section corresponding to your specific fEMG module on the BIOPAC page:  
     • EMG100C 
     • EMG2-R 
3. Open AcqKnowledge and follow the Creating an AcqKnowledge template instructions to create a template for your fEMG module.  
   • On SSH/FSW Lab PCs, create your own folder in C:\ExperimentData (e.g. “Training”).  
   • Save your template as Graph Template (.gtl) in your folder. 

Participant setup

Follow the skin preparation and electrode placement parts of the Protocol described on the fEMG page. Make sure to involve the participant in the process: 

• Explain what fEMG measures 

• Describe the skin preparation and electrode placement process 

• Describe how to use EL-CHECK 

• Ask for consent before touching the participant or preparing their skin 

• Remind the participant they can stop at any time 

Recording the fEMG signal

1. Open the AcqKnowledge template you created earlier. 
2. Start the recording.  
3. Explore AcqKnowledge features: 
   • Use the magnifying glass to zoom into the fMEG waveform. 
   • Right-click the graph > Autoscale Single Waveform or Autoscale Waveforms. 
   • See additional helpful options in the Preferences and View section on the AcqKnowledge page. 
4. Read the Tips & Tricks on the fMEG page. See what happens when:  
   • The participant moves around. 
   • One of the electrodes comes loose. 
   • For the wireless module (EMG2-R), see what happens when the receiver and transmitter lose connection, i.e. move the participant with the transmitter away from the receiver. When the connection starts to deteriorate, the signal will show short flat lines. 

Clean-up

1. Stop the recording and save the recording in the folder you created in C:\ExperimentData. Make sure to save the file as Graph (.acq) file. Close AcqKnowledge. 

1. Follow the Cleaning up section on the fEMG page. 

1. Turn off the BIOPAC. 

Further considerations

Safety

Review general safety information for participant-based research here: Safety - SOLO Research Wiki. 

Markers

Event markers are crucial when measuring physiological data.  

See: 

• Markers and Events - SOLO Research Wiki for more information on markers. 

• Marker channel - SOLO Research Wiki for adding a marker channel to your AcqKnowledge template. 

Equipment choice

BIOPAC has wired (EMG100C) and wireless (EMG2-R) fEMG options. In most studies, any of these modules can be used. Wireless equipment may be preferred when participants need to move around (but beware of movement artifacts in the fEMG signal). Note that wireless connections may drop if the participant moves too far from the receiver. In most cases, it does not matter which equipment is used. 

Compatibility with other signals and equipment

FEMG measurements can often be combined with many other signals and equipment such as EEG, ICG, skin conductance, respiration, blood pressure, ECG, virtual reality, etc. When you want to measure multiple signals with BIOPAC, consult the Grounding section on the BIOPAC page. 

Analysis options

Several software options exist for preprocessing and analyzing fEMG data collected with BIOPAC.  

• We recommend checking out the PhysioData Toolbox, which allows for easy batch-processing of fEMG data.  

• For analysis with AcqKnowledge, more information can be found on the BIOPAC website: AcqKnowledge Data Acquisition and Analysis Software and Webinars | BIOPAC.  

Experimental design

Make sure to consider your preferred measurement outcome when designing your experiment. fEMG can measure subtle muscle contractions that indicate emotions, and electrical patterns that capture their intensity and time course.  

Please check the literature for current recommendations. 

Further reading

• AcqKnowledge webinar: Using AcqKnowledge for Recording & Analyzing Physiological Data. 

• BIOPAC fMEG webinar: How to Record Great Facial EMG Data | BIOPAC