Author: Marketing Department

Analog : Data represented by continuously variable physical quantities, i.e. moving clock hands.

Digital: Data composed of bytes of information sampled at regular intervals.

Data acquisition for life science research and education has come a long way since the heyday of chart recorders and oscilloscopes. Chart recorders, while accurately rendering body signals using an ink stylus on long rolls of paper, lack the flexibility for closely analyzing or interacting with data. Oscilloscopes also pose similar limitations. The field of physiology study received a major assist with the advent of A/D (A-to-D) converters, which include industry-leading BIOPAC MP160, MP36/36R, or Smart Center Systems.
So what is an A/D converter? A/D converters are devices for converting analog signals to a digital format.

This principle can be applied to any type of analog information, such as recorded music or video, and lends itself especially well to conversion of physiological signals. The incoming analog signal (such as an ECG heartbeat) is “digitized,” which allows the signal to be accurately displayed on a computer monitor. During this process, the analog signal is “sliced” into samples per second (or Hz) by the A/D converter. The speed at which the signal slices are acquired is referred to as the sampling rate.

A good illustration of how a sampling rate works is to liken it to a dot-to-dot drawing, each dot appearing at regular intervals and tracing the amplitude and time outline of the incoming analog signal. The higher the sampling rate, the higher the concentration of dots, and the higher the resolution (quality) of the signal. The combined dots, or bytes, of digitized information are displayed onscreen as seamlessly precise waveforms that can be started, stopped, magnified, reduced, edited, autoscaled, transformed, or run through powerful automated analysis routines using BIOPAC AcqKnowledge Research Software.

A good acquisition sampling rate for most physiological data is 2000 samples/second, although certain body signals (such as lung volume measurements) require only 20 samples/second, while auditory studies benefit from a sampling rate as high as 20,000 samples/sec. The BIOPAC MP160 16-Channel Data Acquisition Unit supports sampling rates ranging from 0.1 samples/second to 200,000 samples/second. Try doing that with an analog chart recorder!

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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.

Data acquisition hardware and software packages have undergone rapid progress over the past several years. Cumbersome systems difficult to set up and operate have been superseded by compact modular arrays offering unprecedented convenience, power, and functionality. Researchers and educators in the field of data collection have never had it so good. One of the most oft-asked questions from current prospective end-users is which type of system will best serve my needs?

Wired systems have long been the bedrock of labs around the world. Components fit on a desk and connect to a laptop or desktop computer. The data acquisition unit (such as BIOPAC’s MP160) is combined with a scalable array of modular amplifiers, or in the case of BIOPAC’s MP36 or MP45, powerful functionality is built into an even more compact package. Wired systems generally offer a wider range of features, such as stimulation, MRI signals, gas analysis, laser Doppler flowmetry, pulse oximetry, variable rate sampling up to 400 kHz, more channels (including digital and calculation channels), and online signal averaging. Access to third-party hardware and special licensed features are more readily supported. In wired systems, the subject is tethered to the equipment via cabled transducers and/or electrodes, so if mobility isn’t an overriding concern, a wired system will prove to be a robust platform offering the fullest range of available data collection and analysis tools.

Despite the enhanced functionality offered by wired systems, many researchers and educators have embraced lightweight wireless systems (such as BIOPAC’s BioNomadix, BioNomadix Smart Center or BioNomadix Logger). Wireless systems offer the flexibility of allowing untethered subjects to roam freely, and are excellent for exercise studies or other protocols requiring unrestricted movement. All major physiological signals are supported, and data quality is equal to that of wired systems. Although sampling rates are limited to 2 kHz, this is generally more than sufficient for most physiological studies. The advantage of a wireless system is apparent when fast, accurate results from single or multiple ambulatory subjects are of paramount importance. The BioNomadix Logger even enables subjects to conduct lengthy protocols virtually unlimited distances from the lab, after which the data is downloaded to the computer, enabling researchers to analyze accurate physiological data acquired over time and distance. Certain advanced functionalities available in wired systems aren’t supported in wireless systems, so your lab’s necessity for these must also be carefully considered.

The bottom line is, if your lab requires the full range of available biometric signals in conjunction with advanced functionalities—and subject mobility is not a factor—wired systems are recommended. If compactness, mobility, portability, and access to all major life science signals are deciding factors, then your lab would be well-served by a wireless system.
When your experiment needs flexibility, portability or fast and easy setup, then the wireless Smart Center is the right choice.

Learn about BIOPAC’s newest wireless recording system in “Get Better Physiology Data—BioNomadix Smart Center.”

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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.

Physiology and electricity share a common historical journey. In the mid 1700’s, the Austrian writer/philosopher J. Sulzer noted that when two metal discs were placed on his tongue—one copper and one zinc—the combined metals yielded an odd sensation and taste. He expansively described the copper-zinc taste as “green vitriol.” Although Sulzer did not comprehend the forces behind his observation, he was experiencing was the literal “taste” of electricity generated by the interaction of these dissimilar metals.

Electrical activity generated by the combination of dissimilar metals was further explored by the Italian physician and botanist Luigi Galvani (1737-1798). While poking the leg muscles of a freshly dissected frog with two probes of copper and steel, Galvani was startled when the frog’s leg suddenly twitched. What had happened? The frog was clearly dead. After subsequent frog experiments, some ambitiously involving the use of a metal wire exposed to lightning, Galvani began to refer to this ephemeral twitching activity as “animal electricity.” In 1781, he published his widely-read “Commentarius,” which laid the foundations for modern electrophysiology and neuroscience. In the decades following Galvani’s initial discoveries, this notion of animal electricity as the “spark of life” became the subject of spirited debate, and even found its way into Mary Shelley’s 1818 novel “Frankenstein” as the reanimating force for the title character’s  undead creation.

In 1799, Italian physicist and chemist Count Alessandro Volta (1745-1827), advanced Galvani’s discoveries into the first practical method of generating electricity. Volta rejected Galvani’s “spark of life” notion, and theorized that the “twitching” frog leg activity was not “animal electricity” but the result of an interaction between the frog’s leg and the metals. Volta further realized that the frog’s leg served as both a conductor of electricity (what we would now call an electrolyte) and as a detector of electricity. Using an electric eel as an natural example, he constructed alternating discs of zinc and copper with brine-soaked pieces of cardboard between the metals, which produced an electrical current. This became known as “Volta’s pile” and was the first “wet cell battery” that yielded a reliable, steady current of electricity.

Volta’s doctrine prevailed over Galvani’s until the 1820s, when Leopoldo Nobili used the newly invented “galvanometer” (a compass-like device for detecting electrical activity) to measure the current flowing through a frog’s leg muscle. This gave rise to a host of ghoulish experiments involving half-dismembered animals and severed human cadaver parts. It wasn’t until the 1840’s that researchers Carlo Mateucci and Emil du Bois-Reymond discovered that galvanic measurements of living muscle tissues could be steadily and reliably measured. Du Bois-Reymond pioneered research indicating that living tissue, such as muscle, was composed of “electric molecules,” and the measured electrical activity was the result of this native “electric molecule” behavior.

We now know that these are sodium, potassium, and other ions responsible for maintaining the “membrane potentials” in excitable cells, whether it’s a flexing muscle or a beating heart. Furthermore, these various measurements have unique electrical signatures that can be displayed as waveforms for muscle activity (EMG), heart activity (ECG) or a wide array of other body “signals.” Ultimately, electricity is a fundamental property of living organisms, the understanding of which was arrived at over a century of trial and error.

Watch Beauty and the Origins of Electrophysiology – TEDx talk by BIOPAC founder Alan Macy to learn more now!

BIOPAC offers a variety of industry-leading hardware and software solutions for conducting Electrophysiology* studies. For more information about recording and analyzing body signals using the MP160 and other platforms, please visit the individual application pages on the BIOPAC website. 

*Electrophysiology: the science and branch of physiology that pertains to the flow of ions (ion current) in biological tissues

The NIBP100D-HD provides noninvasive monitoring of blood pressure and hemodynamic measures, representing a big step for noninvasive measurements in physiological research. The device’s accuracy is comparable to clinical measures, allowing researchers to obtain the most accurate data through non-invasive recording.

The NIBP100D-HD monitors blood flow through sensors on the forearm and finger. The device utilizes algorithms to provide continuous data, resulting in precise hemodynamic signals measurements including blood pressure and cardiac output (CNCO). This form of measurement allows not only for accuracy in measuring signals but also in how the signals trend.

Two studies conducted by the national center for biomedical information highlight the device’s clinical accuracy. Researchers Smolle et al. identified potential benefits for noninvasive continuous blood pressure monitoring for ICU patients without an arterial line. In comparing the ability of the NIBP100D-HD to other invasive BP monitors, they found measurements from the device were accurate enough to be interchangeable with data presented from other invasive arterial devices.

In another study, the accuracy of the device’s volume clamp method for determining CNCO was tested in a clinical setting. Researchers Wanger et al. used the system on ICU patients who recently received cardiothoracic surgery, making a comparison between cardiac data from the CNCO to the standard PAC –CO device.  The results showed agreement between the two devices in measuring accurate cardiac output, as well as CNCO’s ability to accurately identify trends in a clinical setting.

Being comparable to clinical devices highlights the NIBP100D-HD’s recording accuracy. Its ability to measure noninvasively allows it to be an alternative solution to invasive arterial systems. Its stability in measuring signals and ability to quickly adjust to signal changes provide researchers with benefits when measuring threat state or emotional responses, where quick changes might influence the signal measurements.

BIOPAC offers a variety of equipment that can be used for noninvasive blood pressure measurement. To find more information on devices similar to NIBP100D-HD, you can visit the NIBP product page on the BIOPAC website.

Thirty-plus years ago, physiological research required incredibly long lab hours and followed by slow analyzation procedures. Prior to the invention of the personal computer (Thank you Steve Jobs and Steve Wozniak!), scientists were burdened with piles of hard copy materials and painstakingly edited data sets by hand. Apple Macintosh and Microsoft Windows transformed the lab process with simple, easy-to-use personal computers. The research industry thrived with these developments and data collection hardware became faster, without the need to support multiple platforms. Physiology technology companies and researchers quickly adapted their hardware, software, and processes to align with the advances in computer science, leading us to the smaller and faster machinery of today.

In the 1980s, hardware products utilized serial ports and ISA serial cards. These serial ports allowed the data exchange to move faster, but researchers still worked with complex hardware set-ups. Responsively, the USB development of 1994 expedited data exchange processes and accelerated lab projects because scientists no longer needed to deal with the complexities of serial ports.

Ethernet technology soon followed and continues to support data exchange and internet service for labs because of its dependability. Rapid technological advancements used among professionals led industry experts to create wearable and sometimes wireless technology for physiology research. Industrial scientific medical radio waves also improved communication so that researchers and developers could work quickly without a paper trail.

Today, the scientific community embraces technological advancements beyond what would have been their wildest dreams in the mid-1980’s before the release of the personal computer. Smart devices, artificial intelligence, and rapid data exchange methods produced advancements that changed our personal and work lives.

BIOPAC’s technology evolved along-side the computing industry. Leading the way in data collection and analysis hardware and software, BIOPAC developed research improvements by producing more efficient, faster and powerful products used in labs across the world, including AcqKnowledge software and BioNomadix wearable devices. Physiology technology improves the classroom and workroom environments of any researcher trying to understand human conditions whether for profit or social justice because subjects can wear devices outside the lab, process information effectively, and synchronize various data sets at once with AcqKnowledge.

BIOPAC equipment can be used in studies for almost any field. To find more information on BIOPAC’s research solutions, visit the individual application pages on the BIOPAC website.

Advancing technology allows researchers the ability to utilize physiological data in different forms. This includes utilizing mathematic models to answer research questions, making data openly accessible to those with similar research questions, and identify alternative approaches to physiological measurements. Studies recently published in the field of biomedical engineering provide examples of these different quantitative approaches.

Researchers Chalacheva et al. (2017) have identified vaso-occlusive crisis (VOC) as a complication unique to sickle cell disease, they wanted to identify if a lab induced VOC reaction was telling about the disease itself. Using heat pulses to evoke a VOC reaction, participants’ reaction were acquired through BIOPAC’s MP research system. Researchers were then able to create a math based model for the use in clinics, which could analyze the severity of sickle cell through measuring evoked VOC reactions.

Chest surface motion can provide insight in how the cardiovascular and respiratory systems act together, researchers Shafiq and Veluvolu (2107) attempted to model chest motion further. ECG, chest motion, and air flow were gathered through BIOPAC’s MP36R research system as participants were given a multitude of breathing tasks. The data acquired was used to create an algorithm to map out chest movements allowing for more precision with radiation therapy in treating lung cancer, which is often challenging and potentially dangerous. The dataset was made openly available, encouraging its use in chest motion modeling as well as other cardiovascular based research.

Blood pressure is an important indicator of various cardiovascular diseases, due to hypersensitive patient’s inability to use pressure cuffs; Shin and Min (2017) identified a need for an alternative form of BP acquisition. BIOPAC’s MP research system acquired the less invasive PPG measurements, the hypothesized as an alternative to blood pressure. The study identified PPG alone can’t be used to measure blood pressure, but allowed for the development of a pressure index for further research in alternative forms of blood pressure monitoring.

The above studies recognize the importance in analyzing trends and sharing data of physiological reactions. If interested in more articles regarding developments in biomedical engineering, visit BIOPACs research publication page. BIOPAC offers a variety of equipment for any research question, find more information on BME biomedical engineering solutions through visiting our applications page.

The cognitive processing of memory affects our individual perception therefore it is important to understand what factors influence an individual’s processing. We have compiled a list of studies that look at how recall can influence individual’s message perception and work to help understand how small cases of memory load or the act of remembering can carry greater implications.

Cognitive Psychology Experiment

Cognitive development is crucial at the preliminary stages of infancy in children. Researchers Brito et al. (2016) examined associations between infants’ EEG power and cognitive abilities such as language and memory and situational factors such as SES. BIOPAC’s EEG100C and electrocap were used to record EEG while the infants were asleep. Overall EEG was then compared to memory and language skills, which were assessed through various tasks while the infant was awake. The findings identified that there are no associations between SES and EEG power, nor was EEG power related to language and memory ability.

EEG and Movie Trailers

University of Pennsylvania researchers studied EEG monitoring to understand how memory recall can influence the effectiveness of an advertiser’s messages. Utilizing a mixed methodology approach, measuring EEG brain activity data and physiological reactance, researchers Barnett and Cerf (2017) created a cross brain correlation (CBC) of 58 participants being exposed to the same 13 movie trailers. BIOPAC’s BioNomadix wireless EEG amplifier recorded EEG data in a commercial movie theater setting. Physiological monitoring solutions included BIOPAC’s respiration belt transducer, and a wireless EDA amplifier. The study’s results suggested that a trailer’s level of memorability could predict the movie’s overall success.

Intrusive Memory Study

One unfortunate side effect of memory is its intrusiveness in perceiving messages. Researchers from Oklahoma State University attempted to identify how worry (an effect of memory load) can influence “attention allocation” and an individual’s ability to process information. In the study conducted by White and Grant, it was hypothesized that, “working memory load will decrease attention allocation during processing of emotional images (White and Grant, 2017).” BIOPAC solutions were utilized in the methodology using an MP research system paired with an EEG100C amplifier as well as AcqKnowledge software. The study compared two groups of participants who were shown a series of similar photos. One group was presented with memory based verbal or visual tasks at the beginning of the experiment. Among other more specified findings, the results indicated that individuals with lower levels of worrying had reduced attention when required to remember visual and verbal memory tasks.

Understanding how cognitive processes and memory relate to one another provides researchers with the opportunity of gaining greater insight into message retention. The foundations of language and memory that we development as infants play key roles in our message retention. These combined with individual attention and outside stimuli show that our memory can inhibit message reception.