Soterix Medical (United States)

The research focuses on the problem of forming an effective information and analytical support system for adapting financial management in e-commerce enterprises to dynamic market changes. The research methodology includes the use of hybrid forecasting methods based on ARIMA-GARCH and neural networks, digital twin modeling of business processes, real-time stream analytics, approaches to AI-based threat analytics in cybersecurity, and dynamic AI pricing with elements of hyper-personalization. The theoretical significance of the study lies in the development of an integrated model that ensures interconnection between analytical, automated, protective, and adaptive components of financial management. The applied value lies in the creation of practical tools for improving forecast accuracy, optimizing costs, reducing financial risks, and enhancing customer interaction in the digital economy. The research results demonstrate that the proposed information and analytical support system enables e-commerce enterprises to adapt financial management to market changes more precisely, rapidly, and securely, while ensuring increased profitability and competitiveness.

Transcranial photobiomodulation (tPBM) is the noninvasive application of light to modulate underlying brain activity. There is increasing interest in evaluating tPBM as a therapeutic option. The typical technological questions are extent of light penetration and associated tissue temperature increases. Limited computational efforts to quantify these aspects are restricted to simplified models. We considered a three-dimensional high-resolution (1 mm) anatomically realistic head model to simulate tPBM with the light source targeting the F3 region at 800 nm wavelength. Power densities spanning three decades (10, 100, and 1000) mW/cm2 were investigated. We also tested time-variant application at 100 mW/cm2 for up to 20 minutes. Finally, tissue temperature increases for the American National Standards Institute safety limit of 330 mW/cm2 also were determined at a test case. Our predictions reveal that the induced cortical irradiance is largely focal, demarcated by the shape and extent of the source. Approximately 1% of the injected irradiance reaches the gray matter. Aligned with previous efforts, the scalp accounts for the greatest loss (∼65%). The irradiance reduces to a hundredth of the value from gray matter at an approximately 113-mm perpendicular distance from its surface. There is a growing halo-like effect at the level of cerebrospinal fluid (CSF), which is extended down to the underlying cortex. The CSF was found to be mainly responsible for this effect. We observe scalp temperature increases of 0.38 °C and 3.76 °C for 100 and 1000 mW/cm2 power density, respectively. The corresponding brain temperature increases are predicted to be 0.06 °C and 0.57 °C. As expected, irradiance absorption is linear with applied power density. Although the maximum induced scalp temperature increases linearly with power density, maximum brain temperature increases less slowly with power density. Transient analysis at 100 mW/cm2 power density indicates expected scalp temperature increase with increasing stimulation duration. Temperature increases asymptote in approximately 10 minutes. tPBM presents unique potential to directly impose a desired spatial profile using simple alteration of the shape and size of the source. Usage of power density of 1000 mW/cm2 exceeds scalp and brain temperature safety limits. Contrary to prior reports, light penetration can exceed >10 cm from gray matter surface.

Introduction:Transcranial temporal interference stimulation (TI, TIS, or tTIS), also known as interferential stimulation (IFS), is able to focally stimulate deep brain regions, provided it is properly optimized. We previously presented an algorithm for optimizing TI using two arrays of electrodes and showed that it can achieve more focal stimulation compared to optimized high-definition transcranial electrical stimulation (HD-TES) and conventional optimized TI using two pairs of electrodes, especially in the deep brain areas such as the hippocampus. However, those modeling studies were only performed on an averaged head (MNI152 template) and three individual heads without exploring inter-individual variability. Existing TI works in the literature mostly utilize a common (possibly optimized) montage of two pairs of electrodes on different individual heads without considering inter-individual variability.Material and method:Here we aim to study the inter-individual variability of optimized TI by applying the same optimization algorithms on N = 25 heads using their individualized head models. Specifically, we compared the focality achieved by different stimulation techniques at six different regions of interest (ROI; right hippocampus, left dorsolateral prefrontal cortex, left motor cortex, right amygdala, right caudate, and left thalamus) under both individually optimized and unoptimized montages. We also conducted numerical sensitivity analysis on the individual optimization and performed phantom recordings to test our models.Results:As expected, there is a variability in focality achieved by TI of up to 1.2 cm at the same ROI across subjects due to inter-individual differences in the head anatomy and tissue conductivity. We show that optimized TI using two arrays of electrodes achieves higher focality than that from optimized HD-TES at the same level of modulation intensity at 5 of the 6 ROIs. Compared to using a common montage either optimized from the MNI152 template or from the literature, individually optimized TI using two pairs of electrodes improves the focality by up to 4.4 cm, and by up to 1.1 cm if using two arrays of electrodes. Focality achieved by the individual optimization is sensitive to random changes and can vary up to 9.3 cm due to the non-lienarity of TI physics. Experimental recordings on a head phantom confirms the drop in TI stimulation strength when using unoptimized montages as predicted by our in silico models.Conclusion:This work demonstrates the need of individually optimizing TI to target deep brain areas, and advocates against using a common head model and montage for TI modeling and experimental studies.

Transcutaneous electrical nerve stimulation (TENS) has been a commonly used modality to relieve aches and pain for over 40 years. Commercially available devices provide multiple therapy modes involving a different combination of frequency and pulse width with intensity. While frequency sets sensation, intensity helps determine tolerability, longer pulse width is reported to induce a feeling of deeper stimulation. In fact, longer pulse width has been empirically shown to deliver current into deeper tissues, but in context of other electrical stimulation modalities. The goal of this study was to unpack the relationship between pulse width and activation depth in TENS. A highly realistic, anatomically-based, 3D finite element model of the forearm was used to simulate the electric field (E-field) distribution, as the pulse width is varied. A typical titration-guided mechanism was used to obtain the strength-duration (S-D) curves of a sensory McIntyre-Richardson-Grill (MRG) axonal model simulating the pain-transmitting A-delta fibers. The pulse widths tested ranged from 30 μs to 495 μs. As expected, shorter pulse widths required more current to achieve activation, resulting in a larger E-field. The S-D curve of the target median nerve indicates a rheobase of 1.75 mA and a chronaxie of 232 µs. When the applied currents are the same, shorter pulse widths result in a smaller volume of tissue activated (VTA) compared to the longer pulse widths. A 21 fold difference in VTA was found between the longest and shortest pulse widths considered. For the conditions tested in the study, an increase in pulse width resulted in an increase in activation depth, exhibiting a linear relationship. Our findings highlight the impact of pulse width on activation depth. While choice of a given therapy mode is usually based on an ad-hoc desirable sensation basis, medical professionals may consider advocating a certain therapy mode based on the depth of the intended target nerve.

We showed evidence that frontal 30 Hz HD-tACS (F30) enhanced acute vigilant attention and associated EEG biomarkers, as compared to motor 30 Hz HD-tACS (M30) [1]. Our analysis used the multimodal GX dataset, one of the largest open-source brain stimulation datasets combining concurrent tES (transcranial electrical stimulation), EEG, ECG, and behavior [2]. With this crossover study design, our between-condition comparisons (F30 verses M30 with no a priori assumption of superiority and a null hypothesis of no difference between groups) demonstrated statistically significant behavioral (compensatory tracking task – CTT) and neurophysiological (delta/theta ratio) changes with no significant differences in cardiovascular heart rate variability (HRV) measures (root mean square of successive differences – RMSSD and low frequency high frequency ratio – LF/HF ratio) or in subjective sleepiness (Karolinska Sleepiness Scale – KSS).

Galvanic Vestibular Stimulation (GVS) is a non-invasive electrical stimulation technique that is typically used to probe the vestibular system. When using direct current or very low frequency sine, GVS causes postural sway or perception of illusory (virtual) motions. GVS is commonly delivered using two electrodes placed at the mastoids, however, placements involving additional electrodes / locations have been employed. Our objective was to systematically evaluate all known GVS electrode placements, compare induced current flow, and how it relates to the archetypal sway and virtual motions. The ultimate goal is to help users in having a better understanding of the effects of different placements. We simulated seven GVS electrode placements with same total injected current using an ultra-high resolution model. Induced electric field (EF) patterns at the cortical and the level of vestibular organs (left and right) were determined. A range of current flow metrics including potential factors such as inter-electrode separation, percentage of current entering the cranial cavity, and symmetricity were calculated. Finally, we relate current flow to reported GVS motions. As expected, current flow patterns are electrode placement specific. Placements with two electrodes generally result in higher EF magnitude. Placements with four electrodes result in lower percentage of current entering the cranial cavity. Symmetric placements do not result in similar EF values in the left and the right organs respectively- highlighting inherent anatomical asymmetry of the human head. Asymmetric placements were found to induce as much as ~3-fold higher EF in one organ over the other. The percentage of current entering the cranial cavity varies between ~15% and ~40% depending on the placement. We expect our study to advance understanding of GVS and provide insight on probable mechanism of action of a certain electrode placement choice. The dataset generated across several metrics will support hypothesis testing relating empirical outcomes to current flow patterns. Further, the differences in current flow will guide stimulation strategy (what placement and how much scalp current to use) and facilitate a quantitatively informed rational / optimal decision.

Background: Transcutaneous electrical nerve stimulation (TENS) has been a commonly used modality to relieve aches and pain for over 40 years. Commercially available devices provide multiple therapy modes involving a different combination of frequency and pulse width with intensity. While frequency sets sensation, intensity helps determine tolerability, longer pulse width is reported to induce a feeling of deeper stimulation. In fact, longer pulse width has been empirically shown to deliver current into deeper tissues, but in context of other electrical stimulation modalities. The goal of this study was to unpack the relationship between pulse width and activation depth in TENS. Methods: A highly realistic, anatomically-based, 3D finite element model of the forearm was used to simulate the electric field (E-field) distribution, as the pulse width is varied. A typical titration-guided mechanism was used to obtain the strength-duration (S-D) curves of a sensory McIntyre-Richardson-Grill (MRG) axonal model simulating the pain-transmitting A-delta fibers. The pulse widths tested ranged from 30 μs to 495 μs. Results: As expected, shorter pulse widths required more current to achieve activation, resulting in a larger E-field. The S-D curve of the target median nerve indicates a rheobase of 1.75 mA and a chronaxie of 232 µsec. When the applied currents are the same, shorter pulse widths result in a smaller volume of tissue activated (VTA) compared to the longer pulse widths. A 21 fold difference in VTA was found between the longest and shortest pulse widths considered. We observed a linear relationship between pulse width and activation depth for the conditions tested in the study. Conclusion: Our findings highlight the impact of pulse width on activation depth. While choice of a given therapy mode is usually based on an ad-hoc desirable sensation basis, medical professionals may consider advocating a certain therapy mode based on the depth of the intended target nerve.