@article {4565, title = {The effect of transcutaneous auricular vagus nerve stimulation on cardiovascular function in subarachnoid hemorrhage patients: A randomized trial.}, journal = {Elife}, volume = {13}, year = {2025}, month = {2025 Jan 09}, abstract = {

BACKGROUND: Subarachnoid hemorrhage (SAH) is characterized by intense central inflammation, leading to substantial post-hemorrhagic complications such as vasospasm and delayed cerebral ischemia. Given the anti-inflammatory effect of transcutaneous auricular vagus nerve stimulation (taVNS) and its ability to promote brain plasticity, taVNS has emerged as a promising therapeutic option for SAH patients. However, the effects of taVNS on cardiovascular dynamics in critically ill patients, like those with SAH, have not yet been investigated. Given the association between cardiac complications and elevated risk of poor clinical outcomes after SAH, it is essential to characterize the cardiovascular effects of taVNS to ensure this approach is safe in this fragile population. Therefore, this study assessed the impact of both acute and repetitive taVNS on cardiovascular function.

METHODS: In this randomized clinical trial, 24 SAH patients were assigned to either a taVNS treatment or a sham treatment group. During their stay in the intensive care unit, we monitored patient electrocardiogram readings and vital signs. We compared long-term changes in heart rate, heart rate variability (HRV), QT interval, and blood pressure between the two groups. Additionally, we assessed the effects of acute taVNS by comparing cardiovascular metrics before, during, and after the intervention. We also explored acute cardiovascular biomarkers in patients exhibiting clinical improvement.

RESULTS: We found that repetitive taVNS did not significantly alter heart rate, QT interval, blood pressure, or intracranial pressure (ICP). However, repetitive taVNS increased overall HRV and parasympathetic activity compared to the sham treatment. The increase in parasympathetic activity was most pronounced from 2 to 4 days after initial treatment (Cohen{\textquoteright}s = 0.50). Acutely, taVNS increased heart rate, blood pressure, and peripheral perfusion index without affecting the corrected QT interval, ICP, or HRV. The acute post-treatment elevation in heart rate was more pronounced in patients who experienced a decrease of more than one point in their modified Rankin Score at the time of discharge.

CONCLUSIONS: Our study found that taVNS treatment did not induce adverse cardiovascular effects, such as bradycardia or QT prolongation, supporting its development as a safe immunomodulatory treatment approach for SAH patients. The observed acute increase in heart rate after taVNS treatment may serve as a biomarker for SAH patients who could derive greater benefit from this treatment.

FUNDING: The American Association of Neurological Surgeons (ALH), The Aneurysm and AVM Foundation (ALH), The National Institutes of Health R01-EB026439, P41-EB018783, U24-NS109103, R21-NS128307 (ECL, PB), McDonnell Center for Systems Neuroscience (ECL, PB), and Fondazione Neurone (PB).

CLINICAL TRIAL NUMBER: NCT04557618.

}, keywords = {Adult, Aged, Blood Pressure, Electrocardiography, Female, Heart Rate, Humans, Male, Middle Aged, Subarachnoid Hemorrhage, Transcutaneous Electric Nerve Stimulation, Vagus Nerve Stimulation}, issn = {2050-084X}, doi = {10.7554/eLife.100088}, author = {Tan, Gansheng and Huguenard, Anna L and Donovan, Kara M and Demarest, Phillip and Liu, Xiaoxuan and Li, Ziwei and Adamek, Markus and Lavine, Kory and Vellimana, Ananthv K and Kummer, Terrance T and Osbun, Joshua W and Zipfel, Gregory J and Brunner, Peter and Leuthardt, Eric C} } @article {4587, title = {Optimal approaches to analyzing functional MRI data in glioma patients.}, journal = {J Neurosci Methods}, volume = {402}, year = {2024}, month = {2024 Feb}, pages = {110011}, abstract = {

BACKGROUND: Resting-state fMRI is increasingly used to study the effects of gliomas on the functional organization of the brain. A variety of preprocessing techniques and functional connectivity analyses are represented in the literature. However, there so far has been no systematic comparison of how alternative methods impact observed results.

NEW METHOD: We first surveyed current literature and identified alternative analytical approaches commonly used in the field. Following, we systematically compared alternative approaches to atlas registration, parcellation scheme, and choice of graph-theoretical measure as regards differentiating glioma patients (N~=~59) from age-matched reference subjects (N~=~163).

RESULTS: Our results suggest that non-linear, as opposed to affine registration, improves structural match to an atlas, as well as measures of functional connectivity. Functionally- as opposed to anatomically-derived parcellation schemes maximized the contrast between glioma patients and reference subjects. We also demonstrate that graph-theoretic measures strongly depend on parcellation granularity, parcellation scheme, and graph density.

COMPARISON WITH EXISTING METHODS AND CONCLUSIONS: Our current work primarily focuses on technical optimization of rs-fMRI analysis in glioma patients and, therefore, is fundamentally different from the bulk of papers discussing glioma-induced functional network changes. We report that the evaluation of glioma-induced alterations in the functional connectome strongly depends on analytical approaches including atlas registration, choice of parcellation scheme, and graph-theoretical measures.

}, keywords = {Brain, Connectome, Glioma, Humans, Magnetic Resonance Imaging}, issn = {1872-678X}, doi = {10.1016/j.jneumeth.2023.110011}, author = {Park, Ki Yun and Shimony, Joshua S and Chakrabarty, Satrajit and Tanenbaum, Aaron B and Hacker, Carl D and Donovan, Kara M and Luckett, Patrick H and Milchenko, Mikhail and Sotiras, Aristeidis and Marcus, Daniel S and Leuthardt, Eric C and Snyder, Abraham Z} }