Marketing Department, Author at BIOPAC Blog

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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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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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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The Eyes Have It—Mobile Eye Tracking

Eye tracking has been a consistent player in the physiological research field for a number of years, and more recently a “mobile” variation of this technology has become increasingly widespread. But just what is mobile eye tracking and how does it work? Unlike eye tracking studies tethered to a lab, where a participant visually follows an object on a computer screen, mobile eye tracking data can be acquired outside of the lab. All that is required, in fact, is a pair of glasses. Not just any glasses, but ETVision glasses, capable of recording not only multiple parameters of a participant’s “eye image” but also the scene the participant is gazing at and responding to. Let’s look briefly on how eye tracking glasses work. The lightweight ETVision glasses are equipped with two eye-facing cameras combined with a pair of LEDs for recording the various components of the “eye image,” such as pupil size/position, gaze path, fixation (when the participant’s eyes lock onto an area of interest), internal and external data markers, vergence angle (angle between the eyes), and corneal reflections (CRs). The cameras also look at the contrast between the pupil and the surrounding iris. This constant real-time feedback is recorded every 5.5 milliseconds and the eye images are rendered at 180 frames per second.

In addition to eye cameras, a built-in forward-facing 720p scene camera records the viewable area in front of the participant. This enables the landscape or scenery the participant is looking at to be combined and synchronized with the eye image data (say, if the participant is driving a car or riding a mountain bike).

Did I say riding a mountain bike? Yes. Full eye tracking data can be collected and stored in a 256 GB SD card and the logged data exported to a .*csv file, which in turn can be imported into AcqKnowledge software along with other logged physiological data. The glasses also have a coated visor for reducing glare. (Glare causes squinting and the eye tracking cameras do not perform as well on eyes that are squinting or closing due to excessive light or reflections.)

In addition, a small microphone built into the eyeglasses enables two-way audio between the investigator and the participant. Already wear glasses? No problem. Eye tracking glasses can be worn over corrective lenses without issue. However, contact lenses should be cleaned before wearing them under eye tracking glasses. The glasses are connected to a small controller via a standard HDMI cable, and the controller houses a 256 GB SD card. In addition to the SD card used for logging remote data, the controller can also be connected to a host computer via WiFi or LAN. The lithium-polymer battery will run the eye tracking glasses for 5.5 hours on a full charge.

Using the AcqKnowledge software’s Media feature, the eye tracking video data can be replayed with a tight correlation to other physiological data collected during the experiment by the BioNomadix Logger. (Other data acquisition hardware types, such as MP160 or MP36R, can be used within the lab.) The eye tracking video and graph data can be displayed side-by-side on the screen. Placing the I-beam cursor at any point in the AcqKnowledge graph takes you to the corresponding point in the eye-tracking video (say, during activities such as driving a car). Eye tracking data for vertical position, horizontal position, pupil diameter, and more can be imported as channels into the AcqKnowledge graph. This data will be synchronized with the eye tracking video, along with any added event markers.

Interested in more details about ETVision Eye Tracking Glasses and AcqKnowledge software? To see it all in action, we invite you to view our free on-demand Mobile Eye Tracking Webinar.

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Top Signals for Life Science Instruction

Experience has shown that beginning physiology students are more engaged when acquiring and viewing signals from their own (or a lab partner’s) bodies in real time, particularly signals that are noninvasive to capture and easy to acquire. Watching a waveform trace across the screen and respond immediately to physical input is a sure-fire way to spark wonder and curiosity in a student. The following is a list (in no particular order) of the most common signals gathered in a beginning lab environment using the Biopac Student Lab System.

Electromyogram (EMG)

EMG is probably the top signal as far as simplicity, as the EMG signal can be consciously and directly controlled by the student, whether it be by simply making a fist to contract the forearm muscle or squeezing a hand dynamometer to measure grip strength. In addition to a raw EMG signal, a second channel showing integrated EMG can be simultaneously displayed. (Biopac Student Lab Lesson 1 and Lesson 2.)

Electroencephalogram (EEG)

EEG is another easy-to-acquire signal. Although not consciously controllable as EMG, the student can observe differences in the four simple periodic rhythms present in brain activity (alpha = 8-13 Hz, beta = 13-30 Hz, delta = 1-5 Hz, and theta = 4-8 Hz) while engaged in activities such as opening/closing eyes, solving simple mental math problems, or hyperventilating. (Biopac Student Lab Lesson 3 and Lesson 4.)

Electrocardiogram (ECG)

The ECG represents electrical events of the cardiac cycle whereas Ventricular Systole and Ventricular Diastole represent mechanical events (contraction and relaxation of cardiac muscle, passive opening and closing of intracardiac valves, etc.). Because the ECG reflects electrical activity, it is a useful “picture” of heart activity and presents several interesting components under various conditions, such as while sitting, standing, lying down, and after deep breathing or exercise. Various lead configurations highlight observable differences in the QRS complex which become apparent in analysis. (Biopac Student Lab Lessons 5, 6, and 7.)

Respiration (RSP) cycle and pulmonary function

As easy as breathing, measuring RSP signals under a variety of circumstances is another common study. Using a respiratory transducer (SS5LB) and an airflow transducer (SS11LB), we can record and analyze chest expansion and contraction during the breathing cycle, as well as pulmonary volumes/capacities and the effects of aerobic exercise. (Biopac Student Lab Lessons 8, 12, 13, and 15.)

Electrooculogram (EOG)

Large and small movements of the eye can be tracked and studied under various conditions by attaching simple adhesive electrodes to the forehead and temples in conjunction with the same SS2L electrode lead set used for recording EMG and ECG signals. (Biopac Student Lab Lesson 10.)

Reaction Time

Possibly the most fun signal to record. The participant holds a hand switch (SS10L) and pushes the button when an aural (click sound) or visual (light flash) stimulus is presented. The reaction time interval between the presentation of the stimulus and the participant’s voluntary reaction (button push) are recorded and analyzed. A variety of stimuli are presented, such as reaction to a fixed stimulus (e.g., every four seconds) opposed to a random stimulus (one to 10 seconds). Reactions are recorded holding the hand switch alternately in both the right and the left hand. It’s interesting to compare the difference in reaction time elicited from the dominant vs. non-dominant hand in response to the aural or visual stimulus. (BSL Lessons 11 and 11A.)

Other signals and studies commonly acquired in Biopac Student Lab are:

EDA and Polygraph (Lesson 9)
Biofeedback (Lesson 14)
Blood Pressure (Lesson 16)
Heart Sounds (Lesson 17)
Spinal Cord Reflexes (Lesson 20)

We also invite you to watch a free on-demand webinar detailing Biopac Student Lab Lessons.

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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Meet Them Where They Are—Portable Wireless Solutions

Once relegated to tightly controlled lab environments where electrode-laden participants were observed at close quarters, researchers are now able to extend the lab into the everyday environment over nearly limitless distances. Top quality physiological data can be acquired from untethered subjects performing tasks ranging from sleeping comfortably in their own beds to engaging in high-impact sports. How and when did this deep dive into unfettered physiology become possible? We offer a brief examination of the solutions currently offered as the 2020s emerge.

BioNomadix BioShirt

Lightweight, comfortable, and some might even say fashionable, the BioNomadix BioShirt uses a respiration sensor and fabric electrodes to wirelessly record respiration and ECG from ambulatory subjects performing unfettered tasks in short or long-term studies, in the lab, or in the real world. The shirt connects to a BioNomadix wireless Respiration & ECG Transmitter (BN-RSPEC) secured in a small pocket on the front of the BioShirt—no electrodes, gels, or wires need apply. Wireless data can be transmitted to a BioNomadix Smart Center, Logger or matched Receiver+MP160/MP150 System. BioShirts provide a high level of comfort and are ideal for long-term physiological monitoring. The ECG and respiratory signal are obtained by means of sensors made of yarns that are fully integrated into the shirt’s textile structure. Sensors are made of fibers directly woven during the production process, and connections between sensors are obtained using conductive fibers for a totally unobtrusive, highly comfortable sensorized garment. The base yarn is composed of anallergic and antibacterial materials to guarantee safe and prolonged use. Machine washable with mild detergent—do NOT use fabric softener.

Smart Center

The BioNomadix Smart Center is a small-form USB-powered data acquisition unit that can record data from up to three wireless BioNomadix transmitters at a time. The transmitters are automatically detected and paired using a guided setup wizard. Smart Center is compatible with 14 different BioNomadix Transmitter types encompassing all major body signals. AcqKnowledge data acquisition and data analysis software also supports monitoring transmitter battery levels, automatic configuration of derived signals and guided analysis based on the type of recorded signals. Adhesive Velcro disks are included for mounting on various surfaces. Smart Center offers a compact and sophisticated physiology platform that sets up in minutes. Simply plug the Smart Center into the computer, set up the transmitters and subject, then start recording high quality data with AcqKnowledge software.

Smart Center Webinar

BioNomadix Wireless Wearable Physiology Logger

Offering the industry’s only system that delivers a comprehensive, 24-hour data logging solution in an easy-to-use, easy-to-wear package, the BioNomadix Logger truly delivers “physiology anywhere.” The BioNomadix Logger is the perfect tool for applications that demand greater degrees of subject freedom and complex experimental design. BioNomadix Loggers wirelessly record physiological data as subjects freely and naturally live their lives.

BioNomadix Logger Webinar

BioHarness Telemetry and Logging Systems

BioHarness with AcqKnowledge software is a lightweight portable biological data logger and telemetry system that monitors, analyzes, and records a variety of physiological parameters including ECG, respiration, posture, and acceleration. BioHarness applications include physiology, psychology, psychophysiology, exercise physiology, ergonomics, human factors, and more. The BioHarness operates in Bluetooth transmitting mode for live viewing of data or data logging mode. In the data logging mode, BioHarness acquires and saves the data for later download to AcqKnowledge software using the included USB docking and charging cradle.

BioHarness in Action

Eye Tracking Glasses ETV

The ETVision (ETV) wearable unit resembles a pair of eyeglasses that can be worn by itself or over the participant’s prescription eyeglasses. The glasses incorporate miniature “eye cameras” for viewing each eye and a “scene camera” that views what the participant is looking at. A built-in microphone is included, and an optional visor can be mounted to the front of the headgear. Recording video and audio data to an SD card for later data processing allows the participant to be completely untethered during data recording. This is useful while engaging in long term activities away from the lab such as walking, bicycling, or driving.

Eye Tracking Fundamentals Webinar

For more information about BIOPAC wireless solutions, we invite you to view the following resources:

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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Eye Tracking Insights

Try Not To Blink—This Won’t Hurt

What exactly, is eye tracking? Do I have to put on a helmet or stick something unpleasant into my eye? No, nothing so invasive, and not the least bit uncomfortable. Eye tracking is the process by which eye movements are recorded for the purpose of tracking where a subject is looking, what he/she is looking at, and the duration of the subject’s gaze on a given area. Eye tracking differs from electrooculogram (EOG) in that it records where and at what the subject is actually looking, whereas EOG primarily records the movements of the eye muscles. Rather than merely recording eye movement and position, eye tracking forges an invisible yet accurate connection between the subject and the objects within the subject’s field of vision. These “visual connections” of where the subject was looking during the study are clearly visible in the resulting data, as dramatic as tire tracks on an impressionable surface.

So how does eye tracking work? Using invisible near-infrared light combined with high-definition cameras, the eye tracking system projects invisible light onto the eye and records the direction from which it is reflected off the cornea. Eye tracking software is used to calculate the exact position and focal point of the eye. The sophisticated combination of eye tracking hardware and software allows for extremely accurate measuring and analyzing of visual behavior and fine eye movements. This makes it possible to create a detailed map of a subject’s field of vision and the specific visual elements honed in on by the subject. Eye tracking data is commonly acquired in tandem with other body signals for the purpose of determining the effects of what we are looking at has on our physiology. Common signals acquired during eye tracking studies are:

EEG (cognitive processes)
EDA (alertness)
ECG (anxiety)
EMG (muscle activity, conditioning)
EGG (pulse, respiration, temperature)

What are researchers looking for when conducting eye tracking studies? Eye tracking data is useful in a variety of different research fields including interface usability, reading analysis, psychological and emotional response, marketing research, training, clinical vision diagnosis, and more.

Eye tracking hardware mainly comes in two flavors. Screen based eye tracking involves having a subject sit in front of a computer monitor while being presented with various types of visual stimuli. A “bar type” eye tracker records the subject’s responses and interfaces with eye tracking software to present the stimulus and store the resulting data for analysis. BIOPAC’s AcqKnowledge software version 5.0.6 and higher, along with the BIOPAC MP160, MP36R, or Wireless Smart Center system, supports fully-integrated eye tracking functionality*. Rather than having to learn a second software program, the familiar AcqKnowledge interface has been extended to incorporate the EYE-TRACK-BAR and EYE-TRACK-BAR-XL remote screen eye tracking systems.

Mobile or “wearable” eye tracking systems utilize a pair of glasses with two types of built-in cameras. One camera faces the subject and tracks eye movements, gaze path, and other parameters, and a second camera (called a scene camera) records what the subject is looking at during the study. Mobile eye tracking allows the subject to engage in independent activities outside the lab, such as driving an automobile. Additional sensors record and log data from other body signals in real time, which can be loaded into the software for subsequent analysis.

For more information about eye tracking, we invite you to sign up for our free “Eye Tracking Fundamentals” webinar to be broadcast live on November 21, 2019 at 8:00 AM PST. Did you miss it or can’t attend? No problem. Follow the same link to watch it on demand.

*Eye Tracking Integration License for AcqKnowledge required.

Please also visit the following links for information about BIOPAC Eye Tracking products.

Eye Tracking Systems

Eye Tracking License

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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