Publications by authors named "Eric Leuthardt"

Cerebral glucose metabolism (CMRGlc) systematically decreases with advancing age. We sought to identify correlates of decreased CMRGlc in the spectral properties of fMRI signals imaged in the task-free state. We analyzed lifespan resting-state fMRI data acquired in 455 healthy adults (ages 18-87 years) and cerebral metabolic data acquired in a separate cohort of 94 healthy adults (ages 25-45 years, 65-85 years).

View Article and Find Full Text PDF

Background And Objectives: Classical biomedical data science models are trained on a single modality and aimed at one specific task. However, the exponential increase in the size and capabilities of the foundation models inside and outside medicine shows a shift toward task-agnostic models using large-scale, often internet-based, data. Recent research into smaller foundation models trained on specific literature, such as programming textbooks, demonstrated that they can display capabilities similar to or superior to large generalist models, suggesting a potential middle ground between small task-specific and large foundation models.

View Article and Find Full Text PDF

Motor rehabilitation is a therapeutic process to facilitate functional recovery in people with spinal cord injury (SCI). However, its efficacy is limited to areas with remaining sensorimotor function. Spinal cord stimulation (SCS) creates a temporary prosthetic effect that may allow further rehabilitation-induced recovery in individuals without remaining sensorimotor function, thereby extending the therapeutic reach of motor rehabilitation to individuals with more severe injuries.

View Article and Find Full Text PDF

Background: Chronic hemiparetic stroke patients have very limited benefits from current therapies. Brain-computer interface (BCI) engaging the unaffected hemisphere has emerged as a promising novel therapeutic approach for chronic stroke rehabilitation.

Objectives: This study investigated the effectiveness of contralesionally-controlled BCI therapy in chronic stroke patients with impaired upper extremity motor function.

View Article and Find Full Text PDF

Entropy measures are increasingly being used to analyze the structure of neural activity observed by functional magnetic resonance imaging (fMRI), with resting-state networks (RSNs) being of interest for their reproducible descriptions of the brain's functional architecture. Temporal correlations have shown a dichotomy among these networks: those that engage with the environment, known as extrinsic, which include the visual and sensorimotor networks; and those associated with executive control and self-referencing, known as intrinsic, which include the default mode network and the frontoparietal control network. While these inter-voxel temporal correlations enable the assessment of synchrony among the components of individual networks, entropic measures introduce an intra-voxel assessment that quantifies signal features encoded within each blood oxygen level-dependent (BOLD) time series.

View Article and Find Full Text PDF
Article Synopsis
  • * The NAVSaH trial aims to test non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) in SAH patients to see if it can reduce inflammation and improve related health complications.
  • * Researchers will assess the effects of taVNS on inflammatory markers, preserved brain function, and reduced occurrences of post-SAH issues like vasospasm and chronic hydrocephalus through a randomized treatment approach.
View Article and Find Full Text PDF

Purpose: High-grade glioma (HGG) is the most common and deadly malignant glioma of the central nervous system. The current standard of care includes surgical resection of the tumor, which can lead to functional and cognitive deficits. The aim of this study is to develop models capable of predicting functional outcomes in HGG patients before surgery, facilitating improved disease management and informed patient care.

View Article and Find Full Text PDF
Article Synopsis
  • This study evaluated the safety and effectiveness of using disulfiram and copper (DSF/Cu) alongside radiation therapy (RT) and temozolomide (TMZ) in newly diagnosed glioblastoma (GBM) patients.
  • It involved administering standard RT and TMZ with DSF and Cu, followed by adjuvant treatment, while tracking drug concentrations in the body.
  • Although the maximum tolerated dose of DSF was 375 mg/d, the treatment showed limited overall success, except for promising results in BRAF-mutant patients, suggesting the need for further research.
View Article and Find Full Text PDF

Background: Inflammation contributes to morbidity following subarachnoid hemorrhage (SAH). Transauricular vagus nerve stimulation (taVNS) offers a noninvasive approach to target the inflammatory response following SAH.

Methods: In this prospective, triple-blinded, randomized, controlled trial, twenty-seven patients were randomized to taVNS or sham stimulation.

View Article and Find Full Text PDF

Introduction: 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.

View Article and Find Full Text PDF

Background: Working memory is essential to a wide range of cognitive functions and activities. Transcutaneous auricular vagus nerve stimulation (taVNS) is a promising method to improve working memory performance. However, the feasibility and scalability of electrical stimulation are constrained by several limitations, such as auricular discomfort and inconsistent electrical contact.

View Article and Find Full Text PDF

Background: Working memory is essential to a wide range of cognitive functions and activities. Transcutaneous auricular VNS (taVNS) is a promising method to improve working memory performance. However, the feasibility and scalability of electrical stimulation are constrained by several limitations, such as auricular discomfort and inconsistent electrical contact.

View Article and Find Full Text PDF

Background: Inflammation has been implicated in driving the morbidity associated with subarachnoid hemorrhage (SAH). Despite understanding the important role of inflammation in morbidity following SAH, there is no current effective way to modulate this deleterious response. There is a critical need for a novel approach to immunomodulation that can be safely, rapidly, and effectively deployed in SAH patients.

View Article and Find Full Text PDF

Background: Focused ultrasound (FUS) combined with microbubbles is a promising technique for noninvasive, reversible, and spatially targeted blood-brain barrier opening, with clinical trials currently ongoing. Despite the fast development of this technology, there is a lack of established quality assurance (QA) strategies to ensure procedure consistency and safety. To address this challenge, this study presents the development and clinical evaluation of a passive acoustic detection-based QA protocol for FUS-induced blood-brain barrier opening (FUS-BBBO) procedure.

View Article and Find Full Text PDF

Unlabelled: Recent clinical trials have highlighted the limited efficacy of T cell-based immunotherapy in patients with glioblastoma (GBM). To better understand the characteristics of tumor-infiltrating lymphocytes (TIL) in GBM, we performed cellular indexing of transcriptomes and epitopes by sequencing and single-cell RNA sequencing with paired V(D)J sequencing, respectively, on TILs from two cohorts of patients totaling 15 patients with high-grade glioma, including GBM or astrocytoma, IDH-mutant, grade 4 (G4A). Analysis of the CD8+ TIL landscape reveals an enrichment of clonally expanded GZMK+ effector T cells in the tumor compared with matched blood, which was validated at the protein level.

View Article and Find Full Text PDF

Limitations in chronic pain therapies necessitate novel interventions that are effective, accessible, and safe. Brain-computer interfaces (BCIs) provide a promising modality for targeting neuropathology underlying chronic pain by converting recorded neural activity into perceivable outputs. Recent evidence suggests that increased frontal theta power (4-7 Hz) reflects pain relief from chronic and acute pain.

View Article and Find Full Text PDF

Single-pulse electrical stimulation (SPES) has been widely used to probe effective connectivity. However, analysis of the neural response is often confounded by stimulation artifacts. We developed a novel matching pursuit-based artifact reconstruction and removal method (MPARRM) capable of removing artifacts from stimulation-artifact-affected electrophysiological signals.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

Sonobiopsy is an emerging technology that combines focused ultrasound (FUS) with microbubbles to enrich circulating brain disease-specific biomarkers for noninvasive molecular diagnosis of brain diseases. Here, we report the first-in-human prospective trial of sonobiopsy in high-grade glioma patients to evaluate its feasibility and safety in enriching plasma circulating tumor biomarkers. A nimble FUS device integrated with a clinical neuronavigation system was used to perform sonobiopsy following an established clinical workflow for neuronavigation.

View Article and Find Full Text PDF

Background And Purpose: Chronic hemiparetic stroke patients have very limited benefits from current therapies. Brain-computer interface (BCI) engaging the unaffected hemisphere has emerged as a promising novel therapeutic approach for chronic stroke rehabilitation. This study investigated the effectiveness of the IpsiHand System, a contralesionally-controlled BCI therapy in chronic stroke patients with impaired upper extremity motor function.

View Article and Find Full Text PDF

Purpose: Glioblastoma (GBM) is the most common and aggressive malignant glioma, with an overall median survival of less than two years. The ability to predict survival before treatment in GBM patients would lead to improved disease management, clinical trial enrollment, and patient care.

Methods: GBM patients (N = 133, mean age 60.

View Article and Find Full Text PDF

Acoustic coupling through hairs remains a challenge to performing transcranial-focused ultrasound procedures. Here, we demonstrated that this challenge could be addressed by using oil as the coupling medium, leveraging oil's high affinity to hairs due to their inherent hydrophobicity. We compared focused ultrasound-induced blood-brain barrier opening (FUS-BBBO) outcomes in mice under three coupling conditions: oil with hairs ("oil + hairs"), ultrasound gel with hair shaving ("ultrasound gel + no hair"), and ultrasound gel with hairs ("ultrasound gel + hairs").

View Article and Find Full Text PDF

Electrical activity at high gamma frequencies (70-170 Hz) is thought to reflect the activity of small cortical ensembles. For example, high gamma activity (often quantified by spectral power) can increase in sensory-motor cortex in response to sensory stimuli or movement. On the other hand, synchrony of neural activity between cortical areas (often quantified by coherence) has been hypothesized as an important mechanism for inter-areal communication, thereby serving functional roles in cognition and behavior.

View Article and Find Full Text PDF

Glioblastoma, a highly aggressive form of brain tumor, is a brain-wide disease. We evaluated the impact of tumor burden on whole brain resting-state functional magnetic resonance imaging (rs-fMRI) activity. Specifically, we analyzed rs-fMRI signals in the temporal frequency domain in terms of the power-law exponent and fractional amplitude of low-frequency fluctuations (fALFF).

View Article and Find Full Text PDF