About

Stephan Eisenschenk MD is an Associate Professor of Neurology at the University of Florida’s Department of Neurology. He attended the University of Florida as an undergraduate in the Medical Honors Program and graduated from the University of Florida College of Medicine in 1993. He completed his Residency and Fellowship in Clinical Neurophysiology, specializing in Epilepsy and Sleep Medicine, at the University of Florida. Dr. Eisenschenk has been on the faculty at UF Health since 1998 and is one of the few physicians nationally board-certified in Clinical Neurophysiology and Sleep Medicine, providing comprehensive assessment of patients and neurodiagnostic studies with over 20 years of clinical and research experience. In 2016, he was appointed Director of the North Florida/South Georgia VAMC Epilepsy Center of Excellence, focusing on the evaluation of veterans with epilepsy and traumatic brain injury. His clinical interests include epilepsy and sleep disorders, with a focus on improving cognitive and physical performance. His research utilizes neurophysiology and neuroimaging modalities to assess cognitive and physical dysfunction, particularly examining the effects of neurological disorders on driving performance.

Research topics

• Medicine
• Anesthesia
• Psychology
• Neuroscience
• Audiology

Selected publications

• Optimizing drug-resistant epilepsy identification in the Veterans Health Administration

  Epilepsy Research · 2025-04-22 · 1 citations

  articleOpen access

  BACKGROUND: Accurate identification of drug-resistant epilepsy (DRE) is crucial for accurate disease measurement, effective clinical intervention and improved patient outcomes. Prior attempts to define DRE in administrative data using the 2010 International League against Epilepsy (ILAE) criteria have faced complexities. METHODS: This retrospective study utilized national administrative data from the Veterans Health Administration (VHA) to identify patients with possible DRE. This was a multicenter national cohort that uses a common, non-commercial medical record system. A panel of six epileptologists conducted chart reviews to identify DRE using the 2010 ILAE criteria. Logistic regression was used to analyze epilepsy-related variables of interest to develop algorithms identifying DRE. RESULTS: Among 260 included patients, 93 (35.8 %) had DRE, 148 (56.9 %) did not have DRE, and 19 (7.3 %) were undetermined. Out of 96 algorithms assessed, the best-performing algorithm had a high accuracy (F1 score=0.726) and defined DRE as those on ≥ 3 ASMs in addition to those on ≥ 2 ASMs for ≥ 365 days with at least one intractable ICD code. The algorithm demonstrated high sensitivity (0.74), specificity (0.81), and area under the curve (AUC 0.78). Factors such as age, number of ASMs, EEG, and MRI procedures, and intractable epilepsy ICD codes were associated with DRE. DISCUSSION: Our optimal algorithm for DRE identification is like previously published algorithms that determined the importance of number and duration of ASMs. However, it differs in the particular combination of factors that best identified DRE. These differences highlight the importance of fine-tuning algorithms for specific care settings. Further validation in a larger, more heterogenous cohort are needed to determine our algorithm's applicability and potential impact.

  PublisherDOI

• Impact of length of stay on diagnostic yield in the epilepsy monitoring unit: A multi‐center retrospective 12‐year Veterans Health Administration study

  Epilepsia Open · 2025-04-29 · 1 citations

  articleOpen access

  OBJECTIVE: Epilepsy Monitoring Units (EMUs) in Veterans Health Administration (VHA) Epilepsy Centers of Excellence (ECoE) are critical for the diagnosis and management of seizure disorders. Whether a shorter length of stay (LOS) in the EMU due to scheduling impacts diagnostic yield is unclear. METHODS: Data from 7074 EMU visits across 15 VHA EMUs (2012-2024) were analyzed. Based on usual admission schedules, EMUs were divided into "fixed" (typically Monday-Friday) or "flexible" subgroups. Diagnostic outcomes were classified as epileptic seizures (ES), psychogenic non-epileptic seizures (PNES), other non-epileptic events, and inconclusive. Diagnostic rates were compared between fixed and flexible sites using cumulative distribution functions and other statistical tests. Readmission data for initially inconclusive cases were also examined. RESULTS: Diagnostic outcomes showed the following distribution: 23% ES, 19% PNES, 11% other non-epileptic events, and 47% inconclusive. Similar distributions were seen between fixed and flexible sites, although a higher proportion of diagnostic admissions were completed earlier in fixed sites and over a longer average LOS at flexible sites. Admissions diagnostic of ES had longer LOS than all other outcomes (4.5 vs. 3.8 days, p < 0.001). Repeat EMU admissions were performed in 10% of patients and were more likely to be diagnostic of ES than PNES or other non-epileptic events. SIGNIFICANCE: About half of EMU admissions within VHA were non-diagnostic with respect to the patients' typical clinical events. ES and PNES were observed at approximately similar rates, although the diagnosis of ES required a longer LOS. Fixed sites did not appear inferior to flexible sites for reaching diagnostic conclusions in our analysis. The higher proportion of earlier diagnoses at fixed sites observed was likely a statistical effect of their predefined shorter admission lengths. Further investigations of EMU resource utilization based on individual goals of monitoring are necessary to better examine and improve efficiency. PLAIN LANGUAGE SUMMARY: Epilepsy Monitoring Units (EMUs) are specialized hospital units used to diagnose and characterize seizures. This study looked at over 7000 admissions across 15 Veterans Health Administration EMUs to see whether length of stay affected diagnosis rates based on admission scheduling and seizure types. Regardless of whether patients were admitted on a fixed schedule (Monday-Friday) or a flexible schedule, about half of hospitalizations did not capture typical events. Diagnosis of epileptic seizures and psychogenic non-epileptic seizures occurred at similar rates, though diagnosing epileptic seizures took longer. Findings suggest fixed (shorter) hospital stays may be as effective as longer flexible hospitalizations.

  PublisherOA PDFDOI

• Automated detection of interictal epileptiform discharges with few electroencephalographic channels

  Epilepsia · 2025-05-03 · 1 citations

  articleOpen access

  Interictal epileptiform discharges (IEDs) are crucial for epilepsy diagnosis and management. New electroencephalographic (EEG) devices with fewer electrodes are more accessible, but their ability to detect IEDs is uncertain. The aim of this study is to determine whether IEDs can be reliably detected in reduced-channel EEG data, enabling broader epilepsy diagnosis. Using EEG samples from 3378 patients and an external validation set of 51 patients, we trained Cyclops, a deep neural network designed to function across various channel configurations. Performance was evaluated using area under the receiver operating characteristic curve (AUROC) and other clinically relevant metrics, including IED source location sensitivity. Cyclops demonstrated strong performance even with minimal channels. AUROC for one channel was .876 (95% confidence interval [CI] = .854-.897); best configuration based on a clinically available product was .950 (95% CI = .936-.962); for the detection of focal IEDs with two local channels, AUROC values ranged from .701 (95% CI = .656-.745) to .930 (95% CI = .902-.955), with a median AUROC of .809. On the external validation set, performance ranged from .692 (95% CI = .593-.782) to .949 (95% CI = .922-.972), with a median AUROC of .846. Thus, Cyclops demonstrates that effective IED detection is possible with reduced EEG setups, enhancing accessibility and expanding epilepsy diagnosis to broader patient populations.

  PublisherOA PDFDOI

• Tiagabine-induced encephalopathy suppressed by vagus nerve stimulation: A case report

  Epilepsy & Behavior Reports · 2024-01-01 · 1 citations

  articleOpen access

  Tiagabine has been associated with reports of status epilepticus as well as encephalopathy, even when used within therapeutic doses. Vagus nerve stimulation (VNS) has been used successfully to reduce seizure frequency in the outpatient setting as well as in the acute setting of status epilepticus. It is also theorized to reduce cortical synchronization. We present a case of a patient on adjunctive tiagabine therapy who developed sudden onset encephalopathy and rhythmic delta activity soon after vagus nerve stimulation was turned off in preparation for magnetic resonance imaging. The bilateral rhythmic delta activity significantly reduced in burden after VNS was turned back on and encephalopathy also gradually improved to baseline. We hypothesize that vagus nerve stimulation successfully interrupted diffuse hypersynchrony, in the form of bilateral rhythmic delta activity, caused by tiagabine. To our knowledge, this is the first report of such a phenomenon.

  PublisherDOI

• Early vigabatrin to augment GABAergic pathways in post-anoxic status epilepticus

  Epilepsy & Behavior · 2024-10-10 · 2 citations

  article
  PublisherDOI

• EEG Infrastructure Within the Veterans Administration: A Survey

  Journal of Clinical Neurophysiology · 2024-11-12 · 2 citations

  article

  PURPOSE: EEG is a vital tool in the diagnosis and management of neurologic conditions prevalent among veterans such as seizures, epilepsy, and brain injuries. This cross-sectional study aimed to assess the state of EEG infrastructure within the Veterans Administration (VA), focusing on availability, utilization, and the potential avenues to addressing gaps in infrastructure. METHODS: This survey was distributed to 123 VA hospitals using the Research Electronic Data Capture (REDCap) platform, gathering data on EEG equipment, staffing, and service provision from June to December 2023. RESULTS: Of the 123 VA hospitals surveyed, 70 responded (56.9% response rate). Most respondents (88.6%) reported having EEG services, although only 38.7% offering continuous EEG (cEEG). Respondents reported having less EEG technologists, machines, and faculty readers than what they thought would be ideal. Significant correlations were found between the availability of resources (e.g., number of EEG machines) and service capabilities, including remote access and cEEG. The use of alternative EEG technologies such as rapid or quantitative EEG varied greatly. Interest in participating in the VA Tele-EEG program was reported by 59.4% of respondents. CONCLUSIONS: There is large variability in EEG infrastructure across the VA. Tele-EEG has the potential to maintain continuity of operations through challenges affecting staffing and to improve EEG service access, especially in resource-limited settings. Expanding access to quantitative, rapid, and tele-EEG services may enhance patient management and may be a potential avenue to explore as the VA continues to invest in and grow its capacity for treating neurologic conditions.

  PublisherDOI

• VIGAB-STAT—A Phase IIa Feasibility Trial of Irreversible GABA-transaminase Inhibition as Adjunct Treatment of Status Epilepticus After Cardiac Arrest (P4-2.003)

  Neurology · 2024-04-09 · 1 citations

  article

  Prove feasibility and study pharmacokinetics of a single enteric VGB load within 48 hours of PASE onset.

  PublisherDOI

• Lateralization of mesial temporal lobe epilepsy with chronic ambulatory electrocorticography.

  2024-02-15

  article

  Objective Patients with suspected mesial temporal lobe (MTL) epilepsy typically undergo inpatient video–electroencephalography (EEG) monitoring with scalp and/or intracranial electrodes for 1 to 2 weeks to localize and lateralize the seizure focus or foci. Chronic ambulatory electrocorticography (ECoG) in patients with MTL epilepsy may provide additional information about seizure lateralization. This analysis describes data obtained from chronic ambulatory ECoG in patients with suspected bilateral MTL epilepsy in order to assess the time required to determine the seizure lateralization and whether this information could influence treatment decisions.

• Abstract 257: VIGAB-STAT- A Phase IIa Feasibility Trial of Irreversible GABA-Transaminase Inhibition as Adjunct Treatment of Status Epilepticus After Cardiac Arrest

  Circulation · 2023-11-07

  article

  Background: Effective therapeutic interventions for post-anoxic status epilepticus (PASE) are lacking. Vigabatrin (VGB) could be an attractive adjunct drug in PASE by increasing GABA availability in inhibitory synapses; however, enteral malabsorption in the post-cardiac arrest (CA) period and difficulty enrolling in the FDA mandatory registry could hinder its use in this setting. We hypothesize that CA survivors absorb VGB despite vasopressor use, concurrent enteral feeding, and regardless of gastric or post-pyloric drug delivery. Goals: Prove feasibility and study pharmacokinetics of a single enteric VGB load within 48 hours of PASE onset. Methods: We administered a single load 1125-4500 mg VGB (based on creatinine clearance; CrCl) in adults with non-traumatic CA, with electrographic SE and gastric or duodenal access. Plasma samples were collected at 0, 0.5, 1, 2, 3, 6, 12, 24, 48, 72 and 168 hours. Results: Interim results from a cohort of 6 subjects comprised of 67% male (4 of 6), 83% White (5 of 6), with a median age 62 years 22-68), median BMI 30 Kg/m 2 (20-53), and median CrCl 44cc/min (22-186) are presented. All subjects received VGB within 48h window; median VGB dose was 2250 mg (1125-4500). The median time to peak (Tmax) was 2 h (1-3); median peak concentration (Cmax) was 38.1 mcg/ml (16.7 -91.8). Median 24h VGB concentration (C24) was 9.4 mcg/ml (3.4-14.2) and half-life (T1/2) was 16 h (10-24). The AUC 0-24 value was 318 mcg*h/ml (262-1012). No significant association was found between sex or BMI and Cmax. Three out of six patients achieved EEG response following VGB load; no association with dose or concentration was noted. Conclusions: All patients achieved detectable VGB levels with peak occurring between 1-3 hours post-administration. Enteric administration of VGB does not preclude phase IIb clinical trials of VGB in PASE. Registration: URL: http://www.clinicaltrials.gov ; Unique identifier: NCT04772547

  PublisherDOI

• Obstructive Sleep Apnea and Stroke: Determining the Mechanisms Behind their Association and Treatment Options

  Translational Stroke Research · 2023-03-16 · 23 citations

  review
  PublisherDOI

Frequent coauthors

• Lawrence J. Hirsch

  32 shared

• Robert E. Wharen

  WinnMed

  32 shared

• Steven N. Roper

  University of Florida

  31 shared

• Martha J. Morrell

  30 shared

• Vicenta Salanova

  Indiana University – Purdue University Indianapolis

  27 shared

• Gregory K. Bergey

  Johns Hopkins University

  27 shared

• Barbara C. Jobst

  Dartmouth Health

  26 shared

• Christianne Heck

  Southern California University for Professional Studies

  26 shared

Labs

• iBRAIN LabPI

Education

• M.D.

  University of Florida