Effect of Short-term Theta Frequency Stimulation of the Vagus Nerve on Cognition in Patients With Refractory Epilepsy

Study Overview
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Brief Summary
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The purpose of this investigation is data pilot study of the effect of theta frequency stimulation of the vagus nerve on cognitive performance in patients with refractory epilepsy. We will compare the effects of no stimulation, theta frequency (5 Hz), and 'standard' beta frequency stimulation (25-30 Hz) on cognitive measures. We hypothesize that theta frequency VNS will have a positive effect on memory retention. The goal of this study to provide initial data to inform the design of a larger clinical trial to examine the efficacy of theta VNS.

Official Title
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Effect of Short-term Theta Frequency Stimulation of the Vagus Nerve on Cognition : a Pilot Study

Conditions
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Refractory Epilepsy

Intervention / Treatment
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* Other: no stimulation
* Other: beta (25-30 Hz)
* Other: Theta (5 Hz)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of Refractory Epilepsy Previously implanted vagal nerve stimulator Willingness and ability to undergo temporary changes to their VNS device settings Exclusion Criteria: <18 years of age Adults unable to consent Pregnant women Prisoners >20 on the Beck Depression Inventory (BDI) <24 on the Montreal Cognitive Assessment (MOCA) Adults with diagnosis of developmental delay, intellectual disability, or traumatic brain injury (TBI). Adults with reported history of learning disability. Adults unable to use a computer with their dominant hand. Status Epilepticus within the past 6 months

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Interventional Model Description: Pilot Study
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: No stimulation<br>All patients will receive three different stimulations | Other: no stimulation<br>* Vagal nerve stimulator will be set to no stimulation<br>|
| Other: Beta (25-30 Hz)<br>Vagal nerve stimulator will be set to Beta (25-30 Hz) | Other: beta (25-30 Hz)<br>* Vagal nerve stimulator will be set to beta (25-30 Hz)<br>|
| Other: Theta (5 Hz)<br>Vagal nerve stimulator will be set to Theta (5 Hz) | Other: Theta (5 Hz)<br>* Vagal nerve stimulator will be set to beta (5 Hz)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| California Verbal and Learning Test 2nd edition group 1 | Test scored with lower values indicating worse memory and higher values indicating better memory. Minimum Value: -16 Maximum Value: 16 | hour 1.5 | 
| California Verbal and Learning Test 2nd edition group 2 | Test scored with lower values indicating worse memory and higher values indicating better memory. Minimum Value: -16 Maximum Value: 16 | hour 2.25 | 
| California Verbal and Learning Test 2nd edition group 3 | Test scored with lower values indicating worse memory and higher values indicating better memory. Minimum Value: -16 Maximum Value: 16 | hour 3 |