Refractory Epilepsy
Conditions
Keywords
Vagus nerve stimulation, Transcutaneous vagus nerve stimulation, Word recognition paradigm
Brief summary
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.
Detailed description
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.
Interventions
DIAGNOSTIC_TESTMemory task
Word recognition task
Sponsors
University Hospital, Ghent
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Refractory epilepsy * Treated with vagus nerve stimulation * IQ \>= 70 and able to perform the memory task
Exclusion criteria
* IQ \< 70
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Immediate recall score at session 1 | At baseline | Free recall score for correctly recalled words (min score 0,max score 21, higher score indicates better performance), calculated as a percentage |
| Immediate recall score at session 2 | 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 |
| Delayed recognition scores at session 1 | 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. |
| Delayed recognition scores at session 2 | 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
| Measure | Time frame | Description |
|---|---|---|
| Attention score at session 1 | 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 |
| Attention score at session 2 | 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 |
Countries
Belgium
Outcome results
None listed