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Completed

NCT Number: NCT05031208

Acute and Long Term Effects of VNS on Memory in Patients With Refractory Epilepsy

Refractory epilepsy patients implanted with a vagus nerve stimulator perform a memory test at baseline in three conditions: invasive vagus nerve stimulation (VNS), transcutaneous vagus nerve stimulation (taVNS) and sham stimulation. After 6 weeks of VNS treatment, the memory test is repeated in two condition: invasive vagus nerve stimulation (VNS) and sham stimulation.

The endpoint of this experiment is assessing the effect of VNS and taVNS on memory performance.

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Key information

Conditions

Refractory Epilepsy Brain Diseases Central Nervous System Diseases Drug Resistant Epilepsy Epilepsy Nervous System Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University Hospital

Ghent, 9000, Belgium

About this study

Previous studies underlined the potential of both invasive as transcutaneous auricular vagus nerve stimulation to ameliorate certain cognitive functions.

In this randomized, controlled cross-over within-subjects study, a memory test is conducted in patients with refractory epilepsy who are implanted with a vagus nerve stimulation.

The memory test consists out of a word recognition paradigm based on the study of Clarck et al. published in 1999 in Nature Neuroscience. Testing is performed at baseline (before start of the stimulation) and after 6 weeks of treatment with vagus nerve stimulation.

During the first session, the patients complete the word recognition task during three interventions:

  • Invasive vagus nerve stimulation
  • Transcutaneous vagus nerve stimulation (cymba concha)
  • Sham vagus nerve stimulation (no stimulation)

During the second session, the patients complete the word recognition task during two interventions:

  • Invasive vagus nerve stimulation
  • Sham vagus nerve stimulation (no stimulation)

The goal is to investigate if invasive vagus nerve stimulation and transcutaneous nerve stimulation can influence (i.e. improve) the performance on the memory task and if this performance is improved after 6 weeks of VNS treatment.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Refractory epilepsy
  • Treated with vagus nerve stimulation
  • IQ >= 70 and able to perform the memory task

Exclusion criteria

  • IQ < 70

Treatment and study plan

Memory task

Diagnostic Test

Word recognition task

Primary outcomes

  1. Immediate recall score at session 1

    Time frame: At baseline

    Free recall score for correctly recalled words (min score 0,max score 21, higher score indicates better performance), calculated as a percentage

  2. Immediate recall score at session 2

    Time frame: After 6 weeks of VNS treatment

    Free recall score for correctly recalled words (min score 0, max score 21, higher score indicates better performance)), calculated as a percentage

  3. Delayed recognition scores at session 1

    Time frame: At baseline

    Hitscore for correctly recognized target words (min score 0,max score 63, higher score indicates better performance), score for not recognized target words= misses (min score 0,max score 63, higher score indicates worse performance),correct rejection score of non-target related words (min score 0,max score 63, higher score indicates better performance), score for incorrect recognition of non-target related words= false alarms (min score 0,max score 63, higher score indicates worse performance), discrimination index= hit score -false alarm score (min score 0,max score 63, higher score indicates better performance). All scores are calculated as a percentage.

  4. Delayed recognition scores at session 2

    Time frame: After 6 weeks of VNS treatment

    Hitscore for correctly recognized target words (min score 0,max score 48, higher score indicates better performance), score for not recognized target words= misses (min score 0,max score 48, higher score indicates worse performance),correct rejection score of non-target related words (min score 0,max score 48, higher score indicates better performance), score for incorrect recognition of non-target related words= false alarms (min score 0,max score 48, higher score indicates worse performance), discrimination index= hit score -false alarm score (min score 0,max score 48, higher score indicates better performance). All scores are calculated as a percentage.

Secondary outcomes

  1. Attention score at session 1

    Time frame: At baseline

    Score of correct responses on 6 open question (min score 0, max score 6, higher score indicates better performance), calculated as a percentage

  2. Attention score at session 2

    Time frame: After 6 weeks of VNS treatment

    Score of correct responses on 6 open question (min score 0, max score 6, higher score indicates better performance), calculated as a percentage

Sponsors and collaborators

Lead sponsor

University Hospital, Ghent

Other

Registry information

Official study title

Research on the Acute and Long Term Effects on Memory and the Mechanism of Action of Vagus Nerve Stimulation in Patients With Refractory Epilepsy

Important dates

Study start
2018
Primary completion
2020
Study completion
2020
First posted
Sep 1, 2021
Registry last updated
May 6, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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