Cutting Through the Noise—Simple Ways to Remove Artifact

With the variety of modern data acquisition tools at our disposal, acquiring high quality physiological data has become much less of a challenge than in times past. Following some basic guidelines will usually result in very good data without a lot of mystery or guesswork. But because there is no perfect scenario, there are occasions when unwanted noise or artifact creeps into the data, which can skew the analysis. Formerly, we were stuck with these outliers in the data, and forced to ignore or compensate for them in some fashion.

An analogy to this can be found in the way music is recorded. In the early days of recorded music, not only was the sound quality poor, the performance was recorded directly to a wax cylinder. If the performance was flawed, or the musician shuffled his feet or made some other bodily sound, it was immortalized. The stakes were very high for delivering a technically perfect performance. With the advent of magnetic tape, it became easier to correct errors by repeating a performance until a good take was achieved, or even splicing tape from different performances together. However, in modern digital recording, the degree of control over unwanted artifact or small errors is surgically precise. if a noise creeps into an otherwise faultless recording, the flaw can often simply be snipped out of the performance, leaving the good parts intact. Larger errors can be corrected via edits or equalizing out unwanted frequencies.

This is similar to what we can achieve with modern data acquisition software such as AcqKnowledge or BSL PRO. There is a robust suite of tools for eliminating noise or artifact from an otherwise usable experiment. Let’s briefly explore some of these tools.

If the data is simply a bit noisy overall, median smoothing is a very effective tool for removing artifact because it removes the fast-moving components that are noise related. Noise can be identified as “blips” in the waveform that are not physiologically related. Smoothing helps tone this artifact down and add clarity to the waveform. Smoothing can be pre-emptively applied in a calculation channel while recording or applied after the acquisition as a transformation.

There are also a number of filters that can be applied, such as FIR, IIR, Adaptive or Comb Band Stop. The type of filter used is often dictated by the type of data being acquired. For example, EDA skin conductance data can be enhanced by performing median smoothing followed by a low pass IIR filter fixed at 1 Hz.

A quick way to remove a “blip” or noise artifact over a small area is to simply select the portion of data in the waveform containing the blip and select Transform > Math Functions > Connect Endpoints. This action performs a linear interpolation between the left and right edges of the selected area, effectively removing the artifact and leaving the valid data intact.

There are also processes in AcqKnowledge for setting up automated scripting to comb through the data and remove detected outliers. This is especially useful for long experiments where it might become tedious to scroll through and manually identify areas of noise and artifact. Once the script is set up, it can be accurately repeated on subsequent data files with one click.

This brief journey represents but a small sampling of the tools available for removing imperfections and non-physiological artifacts from data. For a more in-depth look at enhancing and refining data, we invite you to view the following free, on-demand webinars.

BIOPAC offers a wide array of wired and wireless equipment that can be used in your research. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, respiration, and more using any platforms mentioned in this blog post, you can visit the individual application pages on the BIOPAC website.

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A Brief Tour of Psychophysiology

Why are we interested in psychophysiological measurements? Which measurements are these exactly? By “measurements,” we are talking about micro-facial expressions, pupil dilation, peristaltic contractions of the intestines, heart activity, breathing patterns, electrodermal activity, and other responses not visibly apparent.

In the 1880s, an English philosopher named William James was among the first to explore what constitutes an “emotion.” James believed that everything, big and small, that happens to us and around us elicits a constant stream of feelings and responses. These responses can range from indifference, fear, excitement, happiness, stress—virtually the full gamut of the human emotional palette.

Why does this happen and how do we measure it?

There is always a response in our bodies as a consequence of input delivered via our senses, and there is a resulting “feeling” that happens. Sometimes the feeling doesn’t have much impact but at other times, its effect is profound. The term “emotion” is the label that we assign to these feelings. These feelings result in a response that affects our physiology. These physiological responses to ongoing events are objectively measurable and referred to as “affect.”

Data enters the brain via our senses, but it takes a small period of time to process the input; about 50 milliseconds if the event is a sound, and 100 milliseconds if visual. When data comes in, it travels through various neural pathways and our response to it is informed by our previous experiences. An extreme example to external input causing profound affective changes would be in someone with post-traumatic stress disorder (PTSD), in which certain sounds, or other situational input can trigger pronounced panic or discomfort. People with phobias (for example, fear of cats) will exhibit physiological changes far out of proportion to the actual danger posed by the perceived input. Someone who loves cats would undoubtedly experience a warm fuzzy feeling, whereas a person with a cat phobia would be panicked, resulting in dramatic and measurable changes in heart rate, respiration, and eccrine activity (skin sweating).

An evolutionary motivation baked in to our consciousness is the “fight or flight” response, in which we respond to danger and make a quick decision whether to run or defend ourselves. We all have different thresholds for which input might trigger this response. The line is often blurred between what constitutes actual danger or a seemingly innocuous sensory event that ignites an unpleasant memory or triggers the ghost of a previous traumatic experience.

Now that we have briefly explored a thumbnail sketch of psychophysiology, what kind of equipment is used for recording psychophysiological data? When we set up a psychophysiology experiment, we can record the changes occurring in the body and analyze the results with a great depth of accuracy. To record these signals, specific data acquisition hardware such as the BIOPAC MP36 is commonly used, with a SS2L transducer for recording ECG and a SS57L EDA (electrodermal activity) transducer. The software used to process and display these signals is very often AcqKnowledge (for research) or Biopac Student Lab (for education).

Although emotions cannot be captured or studied in a lab, the physiological changes that result from emotional experiences certainly can be.

For further reading about emotional affect, please see our blog “Circumplex Model of Affect and Motivational State.”

Other related BIOPAC resources:

Webinar: EEG for Psychophysiology Research
Video: Social Support and Psychophysiology Laboratory Training

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Fielding a Media Psychophysiology Team

Author: Ashley Churchill, M.A., BIOPAC Midwest Sales

Media psychophysiology research is being embraced by a variety of communication departments around the world. Media psychophysiology generally refers to the measurement of biological responses to messages in order to understand viewers’ cognitive and emotional processing of video, audio, or print messages. Media researchers often focus on measuring processes that occur as one interacts with media content over time and they look for insights into how and why certain media effects emerge (see Potter & Bolls, 2012 for more background).

Social science labs and communication researchers might feel daunted when starting up a lab if they are inexperienced in collecting physiology data. Here are three common strategies that will support the development of a media lab team and contribute to its success.

Ensure the research team has access to and is comfortable seeking out assistance from a variety of resources. Psychophysiology is a fundamentally interdisciplinary science. Incorporating it into your research requires that you draw on both technical and conceptual knowledge from disciplines outside of social science. To complicate things, formal psychophysiology resources can be difficult to find within the typical social science department. Effectively using external resources like subject librarians, university IT, faculty across departments, and BIOPAC’s support team, can help overcome this challenge.

Explain the conceptual aspects of media psychophysiology to your research assistants, whether they are volunteering for the semester or plan to stick around for a few years. Providing RAs with a conceptual background regarding relationships between media, psychology, and physiology can mean the difference between success and failure as far as effectively identifying and resolving problems during an experiment. It takes more than simple knowledge of electrode placement to make someone effective in a data collection role. Guiding RAs in a way that reflects this supports stronger research and researcher retention.

Preserve the practical knowledge generated by your team, do not let it leave with them. Learning how to conduct media psychophysiology research takes time and experience. As different team members rotate in and out of the lab over time, continue to support lab practices that preserve their knowledge and understanding of this research approach. Whether this takes the form of storing informative documentation or encouraging them to lead aspects of new member onboarding, these practices are important to improving the effectiveness of your team over time.

To find more information regarding media psychophysiology, check out our recent webinar featuring media psychophysiology expert Dr. Paul Bolls. To learn about signals that are common in media psychophysiology research— like fEMG, ECG, and EDA—visit our library of on-demand life science webinars.

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Panoply of Respiration and Pulmonary Measurements

The respiratory or pulmonary system performs the important functions of supplying oxygen (O₂) during inhalation, removing carbon dioxide (CO₂) during exhalation, and adjusting the acid-base balance (pH) of the body by removing acid-forming CO₂.

All humans and animals require oxygen to carry out cellular processes of energy transformation essential for life. During cellular metabolism, oxygen is consumed when nutrients such as protein, carbohydrate and fat are oxidized, and carbon dioxide is produced as a gaseous waste product. Collectively, the processes whereby oxygen is taken up from the atmosphere, delivered to body cells and consumed, and the processes of producing carbon dioxide and delivering it to the lungs for excretion into the atmosphere constitute respiration.

Processes of respiration fall into one of three categories: external respiration, gas transport, and internal respiration. External respiration refers to mechanisms by which a person obtains oxygen from the external environment and eliminates carbon dioxide into the external environment. Gas transport refers to mechanisms used to distribute oxygen to and remove carbon dioxide from cells. Internal respiration refers to the chemical reactions of cellular metabolism in which oxygen is consumed and carbon dioxide is produced.

Gas exchange between the air in the lung and the blood is a process of simple diffusion. A gas diffuses from a region of higher concentration to a region of lower concentration, or, from an area of higher partial pressure to an area of lower partial pressure. Partial pressure is simply a way of expressing the concentration of gas molecules.

Blood transports gases to and from the body’s cells. The respiratory system supplies oxygen to the blood and removes carbon dioxide from the blood. At the beginning of inspiration, the thoracic cavity is enlarged by contraction of the diaphragm and the external intercostal muscles. Expiration begins when the inspiratory muscles relax. The diaphragm returns to its resting dome shape, decreasing thoracic and intrapulmonic volume.

What are some common measurements extracted when we measure respiration and how are these measurements acquired and analyzed?

Pulmonary Airflow — The pulmonary airflow analysis uses a calibrated airflow signal from a pneumotach transducer, of which there are many types for various airflow applications.

Compliance and Resistance Analysis is measured on a breath-by-breath basis by diving tidal volume by change in pressure between the exhale start and inhale start locations of the breath.

Respiratory Gas Analysis uses the BIOPAC O2100C and CO2100C amplifier modules for measuring and analyzing oxygen and carbon dioxide content.

Anaerobic Threshold uses AcqKnowledge software to establish a ratio of inspired volume and VO₂ consumption and to integrate the air flow signal to obtain total inspired volume in real time.

Respiratory Exchange Ratio is determined by dividing VCO₂ produced by VO₂ consumed. An automated script for computing RER is available via download from BIOPAC.

Respiration, Gas Analysis, Pulmonary Function, and Exercise Physiology for Research applications and Education curriculum are available.

Respiratory Cycle and Exercise Physiology are supported by the new BSL HOME Practical Lab Kit, enabling students to keep abreast of curriculum demands while safely distanced.

We invite you to sign up for BIOPAC’s free How to Record Great Respiration Data webinar on demand. You may also watch archived webinar events on demand by visiting our Webinars page.

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Libraries in 2020: From Curbside Pickup to Practical Lab Kits

Libraries can support remote students with distance learning tools like BSL Home practical lab kits, accessible wifi or hotspot loaners, and more.

By: Jasmine Anderson, Biopac Student Lab Product Manager

People call the library the heart of the university campus, which speaks for the memories students and alumni associate with it. It’s the essential college stomping ground and uniquely serves as both a quiet refuge for studying and a meeting place for free-flowing ideas. At the library, peers mingle, study groups collaborate, and you can find solace from the stress of student life between the book stacks. Well, at least that was true before COVID-19…

Now facing the pandemic, libraries are performing their own open-heart surgery to maintain the flow of shared knowledge and support a thriving academic experience. They are redesigning ways to safely provide information and tools to students, facilitating inter-disciplinary course reserves and collaboration, and helping to maximize resource funding and logistics across campus.

“Quiet, please” doesn’t apply these days…talk to your librarian to discover new funding options!

To maintain their role in the college experience while also evolving with the recent changes to academia, libraries are adopting electronic print collections, virtual technology, and self-service stations. Adding these services—along with the infrastructure for self-checkout, curbside pickup, and the ability to loan technology such as laptops, anatomical models, and lab kits—helps support the transition to distance learning at universities.

Libraries can also help students in the sciences by providing funding for portable lab kits to fill the gap left by practical lab closures. In the fall, students can reserve BSL Home kits on loan from the library to participate in hands-on physiology experiments from anywhere. With BSL Home, students record and analyze data from their own bodies and receive the same authentic, open-ended, and complex learning framework that’s true of the traditional lab.

To champion this, the Association of College & Research Libraries (ACRL) put forth guidelines for instruction programs stating that libraries should demonstrate a “commitment to purchasing and providing support for classroom technologies.” Alongside the University of Wisconsin, several other institutions are following suit by providing resources and funding to support classroom technologies. A handful of these universities are listed below with their library action plan (Table 1).

Institution/University Library	Action Plan
Auburn University	Auburn’s subject librarians offer services to help faculty by purchasing books, journals, and electronic resources as well as supporting teaching and research in specific disciplines.
Case Western University	Case Western’s Library equipment borrowing program takes suggestions for what they should be carrying online.
Georgia Southern University	Georgia Southern provides a materials request form that faculty can complete online to request the purchase of teaching and research materials.
Michigan State University	Michigan State allows instructors to request item purchases to place them on course reserve, similar to the University of Wisconsin MERIT Library.
University of California, Santa Barbara	UCSB allows similar reserve requests by directing faculty to make requests to their subject librarians.
University of California, Los Angeles	UCLA utilizes CCLE (Common Collaboration and Learning Environment), a campus-wide service that makes collaboration possible across schools, divisions, and departments and helps to advance remote teaching, learning and research.
University of Nevada, Las Vegas	UNLV takes faculty purchase recommendations through a form on their website which can specifically be recommended to their healthcare library.

Table 1 – A list of Institution/University Libraries paired with their action plan to support classroom technologies.

Even though libraries will not operate in their normal manner this fall, they still remain at the heart of campus life, working to support the student body in stimulating and innovative ways. The students of 2020 won’t have the same memories in the library as classes before them, but with new technology available online and kits to take home, it’s encouraging to see the library continue to be a place of shared knowledge and scholarship. For more information on how your school can accommodate practical labs with BSL Home, talk to your librarian and reach us at info@biopac.com.

Navigating fMRI Data Collection

fMRI (Functional Magnetic Resonance Imaging) is a widely-used noninvasive method for characterizing central nervous system function. But how does fMRI differ from MRI? While fMRI scans use the same basic principles as MRI scans, an MRI generates images of the anatomical structure, whereas an fMRI image reveals metabolic function. Thus, MRI scans can reveal abnormalities such as tumors (particularly when combined with “perfusion,” the introduction of a contrasting agent), while fMRI scans are images of the metabolic activity within these anatomic structures.

MR imaging was originated in 1971 by a chemist named Paul C. Lauterbur who developed a mechanism to encode spatial information into a nuclear magnetic resonance (NMR) signal using magnetic field gradients. Lauterbur was the first to realize that a gradient magnetic field would allow observers to acquire two-dimensional images of an object, which could then be stacked to create a three-dimensional view.

In fMRI studies, participants are placed into an MRI scanner via a “bore” shaped like a giant donut. The magnetic resonance generated during the fMRI allows researchers to correlate the functional brain activity that occurs relative to any number of physiological signals, such as ECG, EMG, EEG, EDA, PPG, and NICO (Noninvasive Cardiac Output). In other words, the portions of the brain activated by changes to these functions can be clearly observed in an fMRI study.

Acquiring these body signals while operating in the MRI environment is a delicate dance. Components that are not “MR Safe” must be isolated from the MRI chamber, and specific cabling and filtering is necessary to preserve the quality and clarity of the signals acquired from participants in the chamber. The static magnetic fields generated by the MRI are measured in units of “Tesla” or “T.” One Tesla corresponds to 10,000 Gauss—for comparison, the earth’s magnetic field is 0.5 Gauss or a mere 0.00005 Tesla. Modern MRI machines are typically rated 3T or 7T, with 7T offering a higher resolution image.

Components used inside the MRI chamber must be “MR Safe,” meaning they must be non-metallic, non-magnetic, and non-conducting. MR Safe components (such as the electrodes attached to the participant) are referred to as “radiotranslucent.” During an fMRI recording, it is important to not coil or twist leads, simply run parallel to the subject and the bore, up to the point of subject attachment, where the leads make a right angle to be attached to the point of interest. Furthermore, as an additional safety precaution, any conductive leads placed across a subject should be thermally insulated from bare skin (via clothing or towel).

The amplifiers used for acquiring physiological signals inside the MRI chamber contain specialized filters for optimizing the signal quality, such as those employed by BIOPAC’s MRI Smart Amplifiers. The amplifiers and MP160 System are placed in the control room and connected to the MRI chamber via special cable and filter sets through a “patch panel,” or shielded interface between the MRI control room and the MRI chamber. The amplifiers and other ferrous components are always physically isolated from the MRI chamber.

For an in-depth look at how fMRI works in concert with BIOPAC components, we invite you to view this free on-demand webinar, “Data Collection in the fMRI Environment.”

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Top 10 Objections to Distance Learning

By: Jasmine Anderson, Biopac Student Lab Product Manager

Simulations are not enough. Students need a practical hands-on lab experience with room to make mistakes.
Internet is not reliable for students or the instructors and reading material alone does not lend to effective learning.
Instructors’ hands are tied with limited budgets for investing in distance learning tools.
Instructors struggle to adapt curriculum to new distance learning programs.
Most lab kits and software are too complicated for students to use without guidance.
Students lose the opportunity to collaborate and troubleshoot together while working in groups.
Many learning tools discourage academic integrity with answers visibly posted online.
Privacy concerns over personal data used in digital lab and simulation tools.
Online e-Learning does not accommodate many learning styles – especially for social and/or kinematic students.
Nothing compares to in-person labs and you won’t find a substitute.

Whether you’ve taught online in the past or are planning for your first time teaching online this fall, most educators agree that it’s not their preferred instruction method. However, the value of online education technology and its innate flexibility became clear this spring when campuses were forced to close early.

Now educators are planning for the fall and are once again having to evaluate how they will meet their learning objectives and goals in an online environment. There’s no question that the landscape of the traditional practical lab is changing, and we are now forced to ask ourselves: what is the “heart” of the practical lab and how can we translate that to the online classroom?

Simulations, virtual labs, and kitchen experiments meet a few of the marks, but none of them touch on the important interpersonal and professional skills gained in the laboratory. How can instructors incorporate communication skills and cooperative learning into the online classroom? And is it even possible to provide that HyFlex (high flexibility) course model given the current online tools?

These are valid and central questions to the new landscape of higher education. After seeing the consequences of the temporary plans put in place by educational institutions in the spring, BIOPAC worked to re-design our student lab systems for the new world of socially distanced learning.

In the old world, students would work around our lab stations in groups, completing guided lessons where they record physiological data from their own bodies. This encouraged cooperative learning, peer-to-peer instruction, and—most importantly—students learned effectively by doing.

With BSL Home, all the above is possible in an online environment. BSL Home includes the same trusted Biopac Student Lab physiology curriculum that is already used in 99% of the top 100 US universities and brings the physiology lab to your students, wherever they are.

BIOPAC can ship BSL Home kits to instructors on campus or directly to a student’s home address. It also comes with affordable purchase options to rent or buy. Unfortunately, the traditional lab is no longer a safe option and simulations or experiments using pipe cleaners and Play-Doh aren’t making the cut.

Practical lab experiments are critical for students that need a Bachelor of Science degree for a career in the medical front line, working in industry, or continuing their education. With BSL Home we can help you preserve your practical lab. For more information on how BSL Home can save your lab this fall, please join us for a live demo and contact us for BSL Home info.

Don’t Let COVID-19 Lock Down Your Labs

By: Jasmine Anderson, Biopac Student Lab Product Manager

The COVID-19 pandemic turned higher education upside-down when stay-at-home orders forced educational institutions to shift to distance learning this Spring. In hindsight, no one could have predicted what 2020 would entail – and now, while facing the pandemic, the future seems even more impossible to plan.

When the novel coronavirus put a lockdown on our higher education institutions, instructors were required to make swift decisions on how they would continue. In the news, institutions are slowly releasing their course of action on an individual basis and plans appear to vary across the board. Some schools are announcing that they’ll forge ahead this fall while others are opting to hold off on deciding or have already closed their campus. Regardless of the plan, a common theme shines through – the fact that everyone’s trying to do the best that they can, given these complicated and un–chartered circumstances.

To help save practical labs, BIOPAC is releasing a new teaching platform, called BSL Home, that brings the lab experience directly to your students. With BSL Home students can learn physiology by recording from their own body and can run the hands-on lessons from their own home, in the dorm, at the library, wherever. The objective of Biopac Student Lab is to learn-by-doing and we’re here to help you navigate this new normal. To find out more about our distance learning solutions and regional events for the Biopac Student Lab community, please contact your local sales representative.

How are you navigating this new normal?

To start the conversation, use the comment box to share your school’s strategy for saving the practical lab this fall.

VR—New Worlds to Explore

Use VR to Expand the Capabilities of Your Lab

The immersive technology of virtual reality (VR) literally offers whole new worlds to explore. Combining VR/Immersive Solutions with Physiology Data allows researchers to create virtual worlds that are impossible or prohibitively expensive in the real world. Additionally, researchers can synchronize VR events with physiological response data to record and analyze physiological, behavioral, and subjective response data. Multimodal stimulation can deliver visual (3D), auditory, olfactory, haptic, and/or electric stimulus to add an incredible degree of realism to the immersive world!

Interfacing a VR workstation with a data acquisition system can add a new dimension to your research by combining objective measures with a tightly controlled experimental protocol. Immersive environments can take the subject anywhere and allow you to unlock the boundaries of your physical lab space and budget.

Create rich 3D environments that are 100% personalized to match your protocol.
Send physiological data back to the VR world to make decisions based on the participant’s physiological responses

Participants can move around naturally within the virtual world while their physiological data is captured. Record any combination of signals: ECG, EDA, EEG, EOG, EMG, EGG, temperature, respiration, and pulse. Include eye tracking to track subjects’ gaze as they view the immersive environment during the experiment. Close synchronization between the stimuli and the physiological signals is achieved through digital markers.

Monitor data in real time and use detailed signal analysis for post-acquisition scoring of the data. Automated analysis routines can streamline the analysis process, eliminate subjectivity, and save time—see AcqKnowledge for some powerful options.

VR software provides you with an unlimited degree of flexibility to create a specific world and control people and items within the world. VR software is easy to use and adaptable, so researchers can make subtle changes to an experiment without having to redesign the entire protocol.

Immerse your subjects in a BIOPAC VR world and record physiological data as the virtual environment influences the subject. Applications are varied and include Psychology, Biomechanics & Kinesiology, Ergonomics, Marketing/Consumer Research, Healthcare, Computer Modeling/Simulation, Education, Training: hazard, medical, etc.,

Use a feedback loop for greater control and automation of the VR world. This allows the world to change in real time, based on the participant’s responses. Timing events are recorded for tight synchronization with physiological data for meaningful analysis.

See VR Resources here for more examples of how VR can expand the capabilities of your lab!

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Answering the challenge of COVID-19

There is no sugarcoating it—we are in some very serious times—and will remain so for the foreseeable future. The COVID-19 pandemic has not only captured the focus of the entire world community, it has illuminated shortcomings in the supply chains required for coping with a global health event of this magnitude. In the absence of a vaccine, only a concerted planet-wide effort involving thorough preparation, cooperation, and transparency will leave us better equipped to forestall a resurfacing of the coronavirus or similar pandemic. Toward that end, countries, states, and communities are scrambling to marshal the necessary PPE and medical supplies, chief among which are life-saving ventilators. In response, key industries are adapting to build vast quantities of ventilators and other much-needed equipment. To help answer this call, BIOPAC has partnered with several corporations to provide time-tested life science components for the specific purpose of testing and validating thousands of newly-made ventilators.

The BIOPAC Ventilator Validation Kit provides ventilator manufacturers and prototype developers with a complete solution for validating new medical/hospital-grade ventilator products intended for human use. The system includes a pulmonary airflow transducer, airway pressure transducer, differential amplifiers, calibration syringe, and a data acquisition system with automated pulmonary function analysis software to assist in the validation of ventilators.

Comprised of existing and evolving BIOPAC research equipment that has for years served with outstanding durability and reliability in the field, we are proud to contribute to the global effort to meet the coronavirus crisis head on.

In the face of adversity, we adapt, we innovate, we assist, and we persevere.

We hope everyone remains safe and well, and offer our deepest condolences to those who have suffered or lost loved ones.

We invite you to view a video about how the Ventilator Validation System works.

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