Life Science Hardware and Software

I think I’ll go to the gym…

Scientists have long used the power of physiological signals to make inferences about cognitive processes. To bridge the gap between physiology and psychology, exercise scientists often find it interesting to look at a person’s encephalographic brain frequencies (EEG) during settings of physical stress, or namely, exercise. Several studies in the past have aimed to evaluate how the mind operates during strenuous training, but what happens when someone just thinks about exercising?

Researchers Berk et al. have recently performed a study in which various athletes were asked to simply sit, close their eyes, and visualize themselves in a state of rest while their brains were monitored for EEG activity. Participants then were asked to visualize themselves in a state of heavy exercise or physical training. The researchers monitored the athletes’ brain EEG signals using a B-Alert X10 Telemetry system. What they found was a significant difference in brain state, primarily shown by the disparity in gamma wave frequency between visualizations of exercise and rest settings. These results suggest that mental visualization of complex physical tasks may support the construction of functional neural networks in the brain necessary for performing them. This study opens the door to subsequent research in order to understand more about the psychology of physical activity. BIOPAC Systems offers the wireless B-Alert X10 EEG system as well as other wearable and wireless solutions for psychophysiological and exercise research. These options include Mobita 32 channel wearable EEG and biopotential systems and the BioNomadix line of wireless biopotential and transducer amplifiers. These products have been consistently proven to provide accurate, reliable data whether the person wearing them is on the field training, or sitting at home just thinking about it.

Cognitive behavioral therapy (CBT) is a common treatment for people who suffer mental health disorders, such as depression and post-traumatic stress disorder. The goal of this treatment is to help reduce many of the symptoms surrounding the patients’ difficulties, including stress, anxiety, and anger. One issue with cognitive behavioral therapy is the subjective nature of the treatment, which often results in high patient dropout rates. Researchers Winslow, et al., proposed an increase in objective, wearable data used during the therapy process in order to lower participant dropout rates. By recording real-time, mobile health data during and after the scheduled sessions, both patient and clinician can monitor mental health symptoms as they occur.

Testing

To test this, the researchers recruited 24 male participants who qualified for the study by completing several response-based tests measuring the psychiatric symptoms that characterize mental health disorders. Participants then began an 8-10 week CBT program that included a 60-minute session once a week, a personal log of daily activities, the use of a mobile phone app to indicate stress and set daily reminders, and recorded PPG and EDA data. BIOPAC wireless BioNomadix devices were used to record PPG and EDA data by fitting the devices to participants’ fingers.

Despite nine total participants dropping out of the study, researchers determined the amount of therapy sessions completed before drop out by the experimental group was significantly greater than the control group. A similar trend was found in the quantitative physiological data. Stress and other psychiatric factors, measured by heart rate and EDA data, were significantly reduced in the experimental group. Presented with this data, it is realistic to see tangible results in mental health by using mobile health applications and data recording to improve the success of cognitive behavioral therapy. The authors also noted other applications for mobile health data methods. Real-time physiologic data could help military or medical training instructors monitor their trainees’ response to live stimulus sessions. The impact of this improvement may result in tailored lesson plans that increase appropriate resilience training programs before cognitive behavioral therapy is needed.

The negative effects of stress on the body have been widely studied. Stress can be defined as a situation that is causing the current state, or homeostasis, under pressure to change. The human body’s nervous system reacts to stress by changing the amount produced of certain biomarkers. For example, when heart rate elevates, blood pressure rises and the human body reacts and secretes hormones (epinephrine, cortisol, etc.). Experimenters tested the change in the production of specific biomarkers of people with different training backgrounds to understand how acute psychological stress affects their physiological responses. The three group classifications were sedentary subjects, endurance athletes, and strength athletes.
 
EDA (skin conductance), ECG (EKG), and breathing frequency were measured continuously; BP and cortisol were measured after each experiment segment. EDA, ECG, and breathing frequency were measured during the acute psychological stress test using the BIOPAC MP150 data acquisition unit connected to wireless biopotential amplifiers and recorded on BIOPAC’s AcqKnowledge software.

Psychological stress was induced in participants using a Stroop color-word test and math problems. These problems were presented in a slide show where the subjects had a limited amount of time to solve for the correct answers. The researchers found numerous differences in changes in the biomarkers measured in response to the acute psychological stress activities between the three groups. On average, athletes’ cortisol levels changed differently when compared to the sedentary group. Also, skin conductance was shown to have higher levels in the sedentary group than in the athletes. The athletes also had a higher recovery level for systolic blood pressure, which was observed to decrease over the test for the sedentary group.
 
The participants reported to have experienced psychological stress over the course of the activities and this was reinforced by the change in values of the biomarkers measured. This experiment showed that people with different training backgrounds had different responses to psychological stress for related biomarkers. The experimenters concluded that people with different training backgrounds react differently in their changes of certain biomarkers to psychological stress.

Very little is known about the origins of cardiovascular risk factors like obesity and altered glucose metabolism and their development during childhood. Adolescence is a time when individuals develop their own health behaviors while gaining increasing autonomy from their parents and this development has an effect on their cardiovascular health later in life. The RIGHT Track Health Study is a longitudinal study that followed participants from age two through young adulthood in an effort to understand how self-regulatory behavior throughout childhood alters the trajectory of various cardiovascular risk factors during late adolescence via health behaviors. For this study, individuals in the RIGHT Track program were re-contacted and invited to participate in adolescent data collection in an effort to gain insight into the origins of behavior that could contribute to an increase in cardiovascular risk factors later in life. This information could be valuable to helping researchers and public health policy administrators target intervention efforts in early childhood, when preventing chronic diseases is most cost-effective and behavior is more malleable.

The researchers used an orthostatic challenge to assess autonomic function, via changes in participant’s heart rate variability (HRV), to a mild physiological stressor. This physical stressor was used as a way of comparing the autonomic function to the physiological stressor paradigms that participants underwent during their early developmental years as part of the RIGHT Track program. HRV measurements provided complementary information regarding the role of autonomic nervous system as a regulator of cardiac control. ECG and respiration recorded using a BioNomadix wireless amplifier set with wearable transmitter to collect HRV at rest. Physiological signals were sent to a BIOPAC MP150 Research System with AcqKnowledge software for collecting and exporting the data in real time.

Data from the RIGHT Track Health Study will provide valuable information for youth healthcare about how health behaviors developed during an individual’s adolescence—such as diet, physical activity, sleep and substance abuse—can later affect cardiovascular health and potentially indicate critical times for reducing certain cardiovascular risk factors by assessing their trajectories.