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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.
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:
During the second session, the patients complete the word recognition task during two interventions:
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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Vagus nerve stimulation | Experimental | Invasive vagus nerve stimulation |
|
| Transcutaneous vagus nerve stimulation | Experimental | Cymba concha stimulation |
|
| Sham vagus nerve stimulation | Sham Comparator | No vagus nerve stimulation |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Memory task | Diagnostic Test | Word recognition task |
|
| Measure | Description | Time Frame |
|---|---|---|
| Immediate recall score at session 1 | Free recall score for correctly recalled words (min score 0,max score 21, higher score indicates better performance), calculated as a percentage | At baseline |
| Immediate recall score at session 2 | Free recall score for correctly recalled words (min score 0, max score 21, higher score indicates better performance)), calculated as a percentage | After 6 weeks of VNS treatment |
| Delayed recognition scores at session 1 | 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. | At baseline |
| Delayed recognition scores at session 2 | 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. | After 6 weeks of VNS treatment |
| Measure | Description | Time Frame |
|---|---|---|
| Attention score at session 1 | Score of correct responses on 6 open question (min score 0, max score 6, higher score indicates better performance), calculated as a percentage | At baseline |
| Attention score at session 2 |
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Inclusion Criteria:
Exclusion Criteria:
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University Hospital | Ghent | 9000 | Belgium |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 10195186 | Background | Clark KB, Naritoku DK, Smith DC, Browning RA, Jensen RA. Enhanced recognition memory following vagus nerve stimulation in human subjects. Nat Neurosci. 1999 Jan;2(1):94-8. doi: 10.1038/4600. | |
| 25805212 | Background | Jacobs HI, Riphagen JM, Razat CM, Wiese S, Sack AT. Transcutaneous vagus nerve stimulation boosts associative memory in older individuals. Neurobiol Aging. 2015 May;36(5):1860-7. doi: 10.1016/j.neurobiolaging.2015.02.023. Epub 2015 Feb 28. |
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| ID | Term |
|---|---|
| D000069279 | Drug Resistant Epilepsy |
| ID | Term |
|---|---|
| D004827 | Epilepsy |
| D001927 | Brain Diseases |
| D002493 | Central Nervous System Diseases |
| D009422 | Nervous System Diseases |
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Score of correct responses on 6 open question (min score 0, max score 6, higher score indicates better performance), calculated as a percentage
| After 6 weeks of VNS treatment |
| 29326067 | Background | Colzato LS, Ritter SM, Steenbergen L. Transcutaneous vagus nerve stimulation (tVNS) enhances divergent thinking. Neuropsychologia. 2018 Mar;111:72-76. doi: 10.1016/j.neuropsychologia.2018.01.003. Epub 2018 Jan 8. |
| 25869158 | Background | Steenbergen L, Sellaro R, Stock AK, Verkuil B, Beste C, Colzato LS. RETRACTED: Transcutaneous vagus nerve stimulation (tVNS) enhances response selection during action cascading processes. Eur Neuropsychopharmacol. 2015 Jun;25(6):773-8. doi: 10.1016/j.euroneuro.2015.03.015. Epub 2015 Mar 30. |
| 35132096 | Derived | Mertens A, Gadeyne S, Lescrauwaet E, Carrette E, Meurs A, De Herdt V, Dewaele F, Raedt R, Miatton M, Boon P, Vonck K. The potential of invasive and non-invasive vagus nerve stimulation to improve verbal memory performance in epilepsy patients. Sci Rep. 2022 Feb 7;12(1):1984. doi: 10.1038/s41598-022-05842-3. |