electrocardiography Archives - Page 3 of 4

Best Practices for Recording & Analyzing Data

Over the past several years, tools and techniques for recording and analyzing physiological data recording have seen steady and marked improvement. Modern life science data acquisition systems such as the MP160 System and powerful research-grade software suites such as AcqKnowledge bring high-end physiology tools within reach of the smallest lab. Even with continuing advances and reduced margin for error, it remains prudent to follow some fundamental guidelines for maximizing data quality and clarity.

Preparation is important. First, invest time exploring the system if it’s new or unfamiliar. An overview of the documentation, training videos, and available webinars, as well as some practice runs with the hardware and software will save time and effort when the time comes to conduct a study. This will also build proficiency at identifying the differences between good and poor data.

Next, familiarize yourself with the type of electrodes and/or transducers necessary for the physiological signals you will be acquiring, which includes proper electrode and skin site preparation. For example, gently abrading the skin prior to applying electrodes is normally recommended for most signal types, except for electrodermal activity (EDA), in which case it’s vital to NOT abrade the skin beforehand. It is also helpful to wait at least 5 minutes before starting a recording, which enables the electrode gel to be absorbed into the skin, helping reduce the impedance.

Performing an impedance check to ensure that the electrodes are making good contact with the skin is also highly recommended. This task is made easier by using an Electrode Impedance Checker (such as EL-CHECK), a simple device for quickly measuring the resistance between the skin and the electrode that provides an LED readout of the skin/electrode contact quality. If the resistance is too high (indicating poor contact) proper adjustments can be made before starting an experiment.

For certain signal types, excessive participant movement can introduce unwanted artifact into the signal, resulting in poor or skewed data. Make sure the participant remains as still as possible during studies involving these signals. Using tape to attach the electrode leads to the skin and keep them from moving excessively can also be helpful.

A thorough check of the system and all connections, cameras, and other hardware is important, so that any problems with equipment or setup can be addressed in advance, thus avoiding a show-stopping issue in the midst of an experiment. This would include performing a pilot study with trained personnel in order to head off any unforeseen issues with the data collection.

Creating a lab setup conducive to a relaxed environment for the participant and technician alike will yield better results. This means eliminating clutter, noise, and other distractions that can affect comfort and attention span. Some labs even avoid having their staff wear lab coats because this can heighten participant nervousness.

Keeping detailed notes on successful lab setups is also helpful and will streamline the preparation process for future experiments. Additionally, creating and saving graph templates for regularly-repeated experiments will save further time and effort.

For more about the fundamentals of recording great data, we invite you to view this free on-demand webinar Fundamentals of Physiology Recording.

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.

Photo by John Schnobrich on Unsplash

ECG – The Little Wave You Can’t Live Without

For millennia, ancient healers across the globe long recognized the human heart as immeasurably vital to human life. Other organs may take an occasional time out, but not the heart. This sinewy fist-sized pump contracts and relaxes an average 60 to 80 beats per minute and faithfully repeats this cycle some two and a half billion times over an average human lifespan, constantly driving and recirculating lifeblood through 100,000 miles of veins, arteries, and capillaries. It’s a monumental task that we take for granted, but if the process stops for more than a few minutes, so will this mysterious force we call life.

It’s intriguing to consider the wonder with which the ancients must have contemplated this organ that thumps so audibly. They knew it was of critical importance, and over the centuries learned its form and surface physiology, but what did they imagine animated it? What force kept the heart moving so steadily and faithfully, while remaining implacably divorced from the consciousness of its host? (Go ahead. Try to stop your heart. On second thought, don’t.)

The answer, in a word, is electricity. Although the stethoscope, invented in 1816 by French physician René Laennec, augmented audible heart sounds, it wasn’t until 1901 that Dutch physician Willem Einthoven developed a “string galvanometer,” capable of reliably recording the heart’s electrical activity. Einthoven’s work established a standard configuration for recording the electrocardiogram (ECG) and garnered him the Nobel Prize in 1924. Because the ECG reflects electrical activity, it is a useful “picture” of heart normality or abnormality through the observation and analysis of various distinct components of the cardiac cycle. If there are interruptions of the electrical signal generation or transmission, the ECG changes. These changes can be useful in diagnosing changes within the heart.

The methods for recording ECG have become increasingly sophisticated with the advent of digital technology and have put state-of-the art acquisition and analysis of ECG within reach of not only clinicians, but also researchers and educators. Wired in-lab systems such as the BIOPAC MP160 System with AcqKnowledge software are widely used for Research applications, while the MP36 System with Biopac Student Lab software are the industry standard for physiology education around the globe. Wireless systems such as BioNomadix or BioNomadix Smart Center can be used to collect ECG and other body signals in an untethered environment and the BioNomadix Logger is a great solution for acquiring ECG and other body signals over extended periods outside the lab.

We have come a long way since our forebears contemplated the mysteries of the vital mechanical wonder that beats in every chest, and we now have a myriad of accessible options for unlocking its secrets.

For further exploration of ECG, we invite you to enjoy the following comprehensive free ECG webinars:

Recording Great ECG

HRV & RSA – Fundamental ECG Analysis Techniques

Exercise Physiology – Pulling Out All the Stops

Everyone has experienced showing up at the doctor’s office and being tasked with sitting very still while vital signs are taken. You sit almost trance-like, concentrating on slowing your heartbeat, willing your blood pressure down, avoiding any sudden movement that might affect the signals being monitored for posterity. It’s quite another matter when body signals are being monitored and measured from someone in full motion, particularly an elite athlete, all systems performing at maximum capacity. How are multiple facets of our physiology accurately captured when we are puffing and sweating at full exertion? Don’t these movements introduce artifact into the data and affect its quality? Won’t the result be an unusable mess? The truth is with proper setup and hardware, acquiring accurate signals from exercise physiology subjects has never been easier.

Signals typically and simultaneously acquired during exercise physiology studies are heartbeat (ECG), respiration (RSP), muscle activity (EMG), in addition to oxygen uptake, carbon dioxide production, blood pressure, core/surface temperature data, range of motion, and even GPS, if the participant is performing the activity outside the lab.

An important factor in exercise physiology studies is choosing the right electrodes, as well as their placement. We recommended using long-term electrodes, such as EL502, which can be worn up to 24 hours. If sweat is a problem, use stress electrodes which adhere better and are resistant to moisture. For even better adhesion to contoured parts of the body, use fabric electrodes. It is also important to prep the electrode site correctly, by first abrading the skin using an ELPAD, and making sure the electrode has sufficient conductive gel.

For measuring ECG signals, particularly Lead II, place the electrodes over bone such as a clavicle or rib to minimize movement artifact. For studies involving a lot of abdominal movement, a Lead I ECG configuration is recommended (left and right clavicle placement). This will help assure a good ECG signal during exercise.

If the participant is inside the lab (say, on a treadmill or exercise bike), a “wired” system, such as BIOPAC’s MP160 System with 100D-Series Smart Amplifiers is a good choice. Up to 16 channels of data can be acquired which can be extended to include 16 calculation channels of derived signals or online filters. For more freedom of movement, the MP160 System with BioNomadix wireless transmitters/receivers offer unrestrained comfort, including a BioShirt with built-in ECG fabric electrodes and RSP transducer. The wireless BioNomadix System has a range of 10 meters line-of-sight between transmitters and receivers. For long-term studies outside the lab, the BioNomadix Logger records and logs data for up to 24 hours while the subject goes about their protocol.

An additional wireless system commonly used for exercise studies is the Mobita System. Mobita is wireless, and like the aforementioned systems, works with the MP160 and AcqKnowledge software for recording and advanced analysis. Mobita is compact enough to fit in your hand and will record up to 32 channels of biopotential data.

No reason to keep still or be quiet any longer. With this many choices, acquiring high-quality exercise physiology data over a full range of body signals is within easy reach.

For more information about exercise physiology and how to maximize your results, we invite you to view our free webinar, Recording Great Data from Exercising and Mobile Subjects.

Why Smart Technology Is Smarter

Physiological research studies require a great deal of focused expertise, including an ability to properly set up all necessary equipment for the study at hand. This has long consisted of overseeing a host of manual hardware connections and software settings, and mistakes can be frustrating. The good news is most users become proficient at these detailed configurations, but wouldn’t it be a welcome change if these setups were easier? Think about how helpful it would be if the hardware and software were “smarter” and actively worked on your behalf. This is now a reality with the smart technology offered by BIOPAC’s newly-released line of 100D Smart Amplifiers.

What is smart technology and what makes Smart Amplifiers smarter? To begin with, these amplifiers are significantly smaller than standard amplifiers (only 4.6 mm in length) and have no buttons or switches. The convenient lightweight design is a powerful benefit, enabling these amplifiers to be attached closer to the participant’s body. Because the amp itself is positioned near the signal source(via a lightweight 3-meter cable), the resulting data is of superbly high quality, with less noise and artifact than conventional amplifiers. But let’s get to the smart part. The smart technology in Smart Amplifiers enables them to do the setup work for you. Each Smart Amplifier, regardless of signal type, self-configures to the optimally recommended settings, negating the need for user-defined adjustments or monitoring of physical switch positions. Simply plug the amplifier into the new AMI100D Input Module now included with every BIOPAC MP160 System, launch the AcqKnowledge software, and begin recording data.

To minimize setup time and errors in the lab, Smart Amplifiers utilize auto-detection and auto-identification technology. Not only do they self-configure, they also alert you (via a software dialog) whether the amplifier is connected to the correct channel. So basically, using Smart Amplifiers right out of the box is a three step process. 1) connect the amplifiers, 2) select any desired calculation channels for derived signals, 3) click Record. That’s it.

Frequently-used calculation channels or transformations are pre-configured for all signals and can be enabled by simply checking a box in the amplifier’s software UI. (For example, the ECG100D Smart Amplifier offers options to add heart rate and/or R-R interval, and will automatically place these derived signals in a separate calculation channel in the AcqKnowledge graph.)

Smart Amplifiers are available for the following signals: ECG, EEG, EGG, EDA, RSP, PPG, ERS, EOG, SKT, EMG and new fEMG (facial and small muscle).

Significantly smaller footprint, simple setup, unparalleled user comfort, superlative data quality, compatible with previous-generation BIOPAC amplifiers (such as 100C and BioNomadix Series), portable and lightweight, Smart Amplifiers will be an epiphany for your research.

To see Smart Amplifiers in action, we invite you to watch our free on-demand webinar New Smart Technology for the Lab.

Small and Smaller – Untethered and Unfettered

Advancements in the engineering of data acquisition components have closely paralleled the microchip revolution. Ever-smaller form factors available in wireless transmission formats have resulted in a boon for researchers wishing to collect high-quality physiological data from participants in unfettered environments undreamed of a few years ago.

One of the linchpins of these cutting-edge systems is BIOPAC’s BioNomadix Series of wireless life science transmitters and receivers. BioNomadix modular receiver/amplifiers connect to the mother ship of the acclaimed MP160 System while the bite-sized matched transmitters attach to the participant, or comfortably nestle in a garment such as the BioNomadix BIOSHIRT. Unobtrusive specially designed leads connect to skin electrodes affixed to the participant, and BioNomadix units relying on transducers (such as respiration and skin temperature) offer equal convenience.

An even more streamlined system, the BioNomadix Smart Center, is also available. This system combines BioNomadix transmitters with the Smart Center all-in-one receiver and data acquisition unit. The soap bar-sized Smart Center connects to a computer USB port and supports up to 9 channels of physiological data from up to three wireless BioNomadix transmitters. (All BioNomadix transmitters are supported but connection is limited to three at a time.)

BioNomadix transmitters are dual-channel or dual-signal, with the exception of the Accelerometer, which supports three channels (X, Y, and Z axes).

Acquired signals are of extremely high quality and clarity and are rendered in AcqKnowledge Research Software. BioNomadix systems are available for fourteen body signal types, including ECG, RSP, PPG, EDA, EOG, EEG, EMG, EGG, ACCL, SKT, Goniometer, Dynamometer with EMG, Cardiac Output, and Heel-Toe Strike.

What does all of this mean to the researcher? Nearly unlimited freedom of movement at distances up to 10 meters from the receiver units—opening up new avenues of research and even new vistas in artistic expression.

A stunning and eclectic example of the latter can be taken from this brief performance by Compagnie Linga, a contemporary dance company based in Lausanne, Switzerland. Dancers wore BioNomadix accelerometers to record transmit their movements in real time, which were then digitally rendered in sound. The result is a tableau of dance and self-generated musical accompaniment, an artscape created from the firings of human physiology.

For more information about BioNomadix, please see:

BioNomadix Wireless Amplifiers

BioNomadix Wireless EMG for Neuro-Controlled Prosthetic

Free On-Demand Webinar – Recording Great Data from Exercising and Mobile Subjects

Fundamentals for Recording Great Heart Rate Data: Subject Preparation

Electrocardiography (ECG) or EKG is one of the most commonly recorded signals as it can be used for a wide variety of heart related analysis. Acquiring good, clean data from subjects can prove difficult though. Everything from electrode options to hardware settings can influence ECG signal quality over research. The following guidelines provide a baseline for ECG recording setups to ensure accurate and quality data from participants.

The most common question when recording ECG data is where to place electrodes on the subject. Certain aspects of your research will help inform exactly where to place electrodes. The most important question to answer is what tasks are your participants performing.

For most studies, the ECG placement can be placed by following Einthoven’s Triangle. This incorporates 3 leads; one running along the top of the chest, one running from right should toward left leg, and one running from left shoulder toward right leg. Place electrodes on the clavicle, wrists, or ankles. Note that if participants are moving around, placing on the wrists and ankles can prove difficult so place them instead on the chest area.

Always make sure to prepare your subject before placing electrodes on them. Abrade the skin before placement especially if placing on the wrists or ankles. Double check that the electrode is fresh and apply gel to the electrode for optimal adhesion. About 5-10 minutes after placement, use an impedance checker to check the electrode signal quality. These simple steps can make the difference between clean and noisy data.

If participants have been prepared correctly and the hardware is dialed in, the ECG waveform should resemble the classic ECG example. There are three primary elements to the electrical signal coming from the heart: P-wave, R-wave, and T-wave. Most lead configurations will resemble this waveform example.

These simple, but key guidelines will help ensure that ECG signals recorded from subjects are clean and high quality. Attach electrodes at the right parts of the body given the tasks that the participants will perform. Always make sure electrode sites are clean and that the electrodes are fresh. For more information and further instructions on recording ECG, visit the BIOPAC ECG applications page, ECG video tutorials, or view our ECG webinars.

BIOPAC offers a variety of wired and wireless equipment that can be used in ECG studies. To find more information on solutions for recording and analyzing signals such as ECG, heart rate, and respiration using the MP160 and other platforms, you can visit the individual application pages on the BIOPAC website.

Stressing over the effects of stress

Several studies show chronic stress is typically detrimental to health, while acute stress may be linked to positive effects in addition to the negative counterparts

With April comes National Stress Awareness Month, and it bears noting that different types of stress have varying effects. Where chronic stress is typically detrimental to health, acute stress may be linked to positive effects in addition to the negative counterparts. But is this trade-off worth it?

In a biological psychology experiment testing the effect of oxytocin on acute social stress, researchers found different results between men and women. Subjects underwent several stress tasks while their electrocardiography and impedance cardiography were recorded with a BIOPAC MP Research System and amplifiers. The researchers found that after being given oxytocin during the stressful event, men had less negative affect and women had greater math performance (compared to the control group).

A neurobiology study examined the effect stress had on an extinction memory process when a competing association was paired with a previously aversive cue. To test this, participants were presented with two images, one that was paired with a shock from a BIOPAC bar electrode, and one that was not. Extinction memory training immediately followed this stimulus, with extinction retrieval testing following a day later. Data gathered by a BIOPAC data acquisition system suggested significantly lower retrieval in the group that experienced the acute stress stimulus.

Another biopsychology experiment measured the effect of acute stress on pro-inflammatory cytokine levels in the blood. BIOPAC equipment was used to measure ECG while participants were given the Trier Social Stress Test. After reviewing the data and blood samples, the researchers determined that levels of the cytokine cell, interleukin-1β, increased significantly immediately after the stress test.

The physiological and psychological impacts of stress are clearly multifaceted with many potential results. In some situations, a heightened positive affect or greater analytical thinking may be beneficial. But is this boost in mental performance worth the increase of inflammatory cells and lower memory retention? As with many aspects of life, moderation is the safest answer, ensuring the negative effects do not become chronic problems.

For more information on BIOPAC’s wide range of tools for recording, displaying, and analyzing ECG measurements from human and animal subjects including respiration, heart rate variability, and RSA, visit BIOPAC’s electrocardiography pages and view BIOPAC’s full line of electrodes, amplifiers, and wearable, wireless transmitters and loggers.

BIOPAC Systems, Inc. provides life science researchers and educators with data acquisition and analysis systems that inspire people and enable greater discovery about life. Visit us at www.biopac.com.

Holiday Happiness Part 2: Sounds, Smells, and Self-Reflection

In a previous post, we discussed the stress-reducing benefits of loving interactions with close friends and family during the holiday season. In addition to family, there are many mood-shaping habits and activities that characterize the holidays: the smell of home-cooked meals, seasonal music, and reflection on the past year, to name a few. But do these have a real impact on happiness?

In a psychophysiology study, Matsunaga, et al., tested odor effects on autobiographical memory recall. The researchers introduced several odor stimuli to participants and measured their psychological and physiological reactions. Heart rate and skin conductance were recorded throughout the experiment with a BIOPAC data acquisition system. The odor stimuli resulted in decreased heart rate, increased skin conductance level, and an increase in positive mood states.

Another article tested the effects of meditation on emotional regulation. Participants completed emotional measures before and after a meditation intervention, and had their ECG, respiration, and blood pressure recorded using a BIOPAC MP unit. The meditation correlated with greater participant emotional regulation, as suggested by lower heart rate and respiration.

In addition to meditation and smell, Harmat and Eerola have found music to also be emotionally significant. Participants listened to a musical piece, and then responded to a questionnaire about their emotional state. In addition to measuring pulse rate and facial expressions, the BIOPAC Research System and EDA Amplifier were used to record skin conductance while participants listened to the stimulus. The results found that music samples evoked several emotions, including nostalgia and happiness.

This research suggests that we can affect happiness using subtle techniques that are part of everyday living. To read more studies about psychophysiology and stress reduction, visit the BIOPAC publication page.

BIOPAC offers a variety of equipment that can be used in studies similar to the ones presented. To find more information on solutions for recording and analyzing signals such as skin conductance, ECG, heart rate, respiration, and EDA using the MP160/MP150, and other platforms, you can visit the individual application pages on the BIOPAC website.

Holiday Happiness: Gratitude or Gifts?

Studies investigated the anxiety of gift-giving, the effects of social support in stressful situations, and what impact meditation has on heart rate, ECG, and blood pressure.

December has arrived, and for many the holidays bring a rush to check items off of a long shopping list for parents, siblings, friends, in-laws, and many more. Often we struggle to find that “perfect” gift, but are the physical goods we exchange the true source of the warmth and happiness that characterizes the season?

An article by Nomura investigated anxiety induced by gift-giving. To test this, EDA data was recorded with a BIOPAC data acquisition system and STP100 while participants responded to stimuli. The participants visualized a specific relative while being presented with potential gift options, and were asked how likely they were to purchase the potential gift for that relative. The data found that people who self-reported thinking of in-laws were the most stressed, while those who reported thinking of children or same-gender friends were least stressed.

A psychosomatic study by Inagaki and Eisenberger found that mental and physical well-being benefit from forms of social support. They tested this by administering mild shocks with the BIOPAC STMISOLA to male patients who held the hand of a female partner lying in an fMRI. The results suggest that this support (hand-holding) provided possible stress-reduction for both the male and female participants.

Another article on nonverbal communication and well being by Shaltout, et al. tested the effects of meditation and the subsequent ECG, blood pressure, and heart rate effects. The BIOPAC ambulatory BioHarness and NIBP Blood Pressure System gathered data while participants underwent several mediation episodes, during which they were instructed to focus on loving kindness towards a subject. The results found that participants had decreased heart rate.

Research suggests direct, loving interactions with those who are close to us have many stress-reducing benefits. So when you are shopping for gifts, remember that spending time is more important than spending money. To read more studies about love and stress reduction, visit the BIOPAC publication page.

BIOPAC offers a variety of equipment that can be used in studies similar to the ones presented. To find more information on solutions for recording and analyzing signals such as EEG, EMG, respiration, and EDA using the MP160/MP150, MP36, and other platforms, you can visit the individual application pages on the BIOPAC website.

The Physiology of Election Decision-Making

The psychophysiological factors of stress, the behaviors of others, and of introception can play major roles in decision-making, and BIOPAC systems provide measurements of how physiological factors such as these influence decisions.

People experienced varying stress levels because of the 2016 US presidential election. There are a variety of factors that can impact voting behaviors and decision-making. Several recent studies using BIOPAC systems investigated the psychophysiological effects of stress, the behaviors of others, and introception on decision-making.

Stress has been shown to be very influential in decision-making. In their study, Yamakawa, Ohira, and Mastunga Isowa (2016) investigated effects of acute stress and risk taking in decision-making. Participants were asked to perform a decision-making choice where they either kept or bet the money they were given. Cardiodynamic activity was measured with ECG using a BIOPAC MP system. Results suggest that with an increase in cortisol, adrenaline, heart rate, and subjective stress, participants were likely to make fewer risky choices. So, high levels of stress may be key in helping make better decisions when selecting a future president.

Perhaps it’s not stress that will influence the choice of the next POTUS (President of the United States), but rather the behaviors of others. Work by Bault, Joffily, Rustichini, and Coricelli (2011) sought to compare private and social decision-making to discover the effect of social comparison on risky choices. The objective of the study was to understand more about how individuals evaluated the outcomes of their decisions in private as opposed to in a social context. Combining data from functional MRI (FMRI) and skin conductance recordings, subjects’ reactions were measured using a BIOPAC MP150 System. Researchers found that participants took significantly longer to make a decision in a social setting than in a private one.

In the end, many feel that it is important to listen to your heart when deciding who you find qualified to be the next president. A study by Dunn et al. (2010) examined whether introception moderates the coupling of bodily responses to emotional experience and intuitive decision-making. Bodily response and heart rate were recorded using a BIOPAC Research System and electrodes to measure introception through changes in heart rate. Researchers found that introception was not related to arousal, valence ratings, or heart rate response to images.

For more information on BIOPAC’s wide range of tools for recording, displaying, and analyzing physiological measurements from human and animal subjects including respiration, heart rate variability, ECG and EDA, visit BIOPAC’s psychophysiology page and view BIOPAC’s full line of electrodes, amplifiers, and wearable, wireless transmitters and loggers.