This study is testing whether a gentle electrical stimulation of a nerve in the ear,called the vagus nerve, can help reduce fatigue and improve symptoms in people withPost-COVID Syndrome or Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Thetreatment, known as transcutaneous auricular vagus nerve stimulation (taVNS), isnon-invasive and can be done at home using a small device.Participants will try two different types of stimulation, called Intervention A andIntervention B, to see which may be more effective. Each intervention lasts 4 weeks andwill be separated by a break of at least 4 weeks.Participants will use the device at home twice a day for 30 minutes. Fatigue, quality oflife, sleep, and daily activity will be tracked through surveys and wearable devices. Allparts of the study-including check-ins and data collection-will be done remotely.The goal is to learn whether this type of at-home nerve stimulation can safely improvesymptoms in people with Post-COVID Syndrome or ME/CFS.
The STIMPACT study is a single-blind, randomized, controlled crossover trial designed to
evaluate the efficacy of transcutaneous auricular vagus nerve stimulation (taVNS) in
alleviating fatigue and autonomic dysfunction symptoms in individuals diagnosed with
Post-COVID Syndrome or Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).
Participants will undergo two distinct intervention phases, referred to as Intervention A
and Intervention B, each lasting four weeks and separated by a washout period of at least
four weeks to minimize potential carryover effects. The order of interventions will be
randomized for each participant.
During each intervention phase, participants will self-administer 30-minute stimulation
sessions twice daily using a portable device designed for home use. Adherence to the
stimulation protocol will be monitored through device usage logs and regular virtual
check-ins with the research team.
The primary outcome measure is the change in fatigue levels, assessed using validated
instruments such as the Fatigue Severity Scale (FSS) and the Chalder Fatigue
Questionnaire, alongside daily symptom tracking through electronic diaries. Secondary
outcomes include assessments of quality of life (SF-36, Bell's Disability Scale),
post-exertional malaise (DePaul Symptom Questionnaire - Post-Exertional Malaise
subscale), autonomic function (heart rate variability metrics), sleep quality (Pittsburgh
Sleep Quality Index), daytime sleepiness (Epworth Sleepiness Scale), mood (Hospital
Anxiety and Depression Scale), and physical activity levels (measured via actigraphy).
Data collection will occur at baseline, mid-intervention, post-intervention, and during a
follow-up period, utilizing online surveys, virtual consultations, and data
synchronization from wearable devices. Statistical analyses will employ mixed-model
approaches to evaluate changes in outcome measures over time and between interventions,
with subgroup analyses comparing responses between the Post-COVID Syndrome and ME/CFS
cohorts.
This study aims to provide robust evidence on the potential benefits of taVNS as a
non-invasive, home-based therapeutic option for managing fatigue and autonomic
dysfunction in these patient populations.
Device: transcutaneous vagus nerve stimulation
Transcutaneous auricular vagus nerve stimulation (taVNS) delivered using the CE-certified
tVNS® device (tVNS Technologies GmbH). Stimulation parameters include a pulse width of
250-500 μs, frequency of 10-25 Hz, and an individually titrated intensity (typically up
to 5 mA). The device operates with a 20-50% duty cycle and is used at home.
Other Name: vagus stimulation,tVNS,taVNS
Device: transcutaneous vagus nerve stimulation
Sham stimulation using the same CE-certified tVNS® device. Electrode placement is on the
earlobe, which lacks vagus nerve innervation. Stimulation parameters (pulse width,
frequency, intensity, duty cycle) mirror those of the active condition, with intensity
adjusted to perceptual threshold to mimic the sensation of real stimulation and preserve
blinding.
Other Name: taVNS,Vagus stimulation,tVNS
Inclusion Criteria:
- Diagnosis of Post-COVID Syndrome (persistent symptoms > 3 months post-infection)
- Diagnosis of ME/CFS (following Canadian Consensus Criteria) Aged 18-65
- Moderate to severe fatigue (Fatigue Severity Scale ≥ 5)
- Stable medical regimen for at least 3 months
- Participants who are willing to follow the treatment protocol, and able to comply
with remote monitoring.
- Sufficient proficiency in German or English language
Exclusion Criteria:
- Pacemaker or other implanted electronic or metallic devices
- Neurological or psychiatric disorders unrelated to ME/CFS or Post-COVID Syndrome
- Pregnancy or breastfeeding
- History of vagus nerve damage or significant ear injury
- Previous or ongoing use of taVNS (to ensure effective sham condition)
- Bradycardia (resting heart rate below 60 beats per minute)
- permanent jewelry at close proximity to the ear tragus;
- Known severe coronary disease or recent heart attack (within 5 years)
- Medications that may influence autonomic function, HRV, and fatigue
University of Luxembourg
Esch-sur-Alzette, Luxembourg
Investigator: Nina Buntic, M. Sc.; Doctoral Researcher
Contact: +352 46 66 44 4697
nina.buntic@uni.lu
Investigator: Nina Buntic, M. Sc. ; Doctoral Researcher
Nina Buntic, M. Sc.; Doctoral Researcher
+352 46 66 44 4697
nina.buntic@uni.lu
André Schulz, Prof. Dr. ; Dipl. Psych.
+352 46 66 44 9549
andre.schulz@uni.lu
André Schulz, Prof. Dr. ; Dipl. Psych., Principal Investigator
University of Luxembourg