Persistent post-concussive symptoms (PPCS) affect a significant proportion of individuals following a concussion, leading to debilitating impacts on their quality of life and work capacity. Currently, effective treatments for PPCS are limited, despite their lasting and debilitating impact. Transcutaneous auricular vagus nerve stimulation (taVNS), a non-invasive neuromodulation technique, holds promise as a therapeutic option by leveraging the bottom-up modulation of brain activity via the auricular branch of the vagus nerve. This study aims to evaluate the neurophysiological and clinical effects of taVNS on brain activity and symptomatology in patients with PPCS through a randomized, controlled, double-blind trial.
Age between 18 and 65;
Between 4 weeks and 1-year post-diagnosis of a concussion;
Score equal or above 16 on the Rivermead Post-Concussion Questionnaire;
Intact skin at the electrode site.
History of chronic neurological or psychological disorders (still untreated 6 months preceding inclusion);
Pregnancy or breastfeeding;
Presence of an active implant (e.g., pacemaker, cochlear implant);
History of myocardial infarction or cardiac arrhythmia;
Parallel
Active taVNS
DevicePatients will receive active taVNS for 15 consecutive days, with each session lasting 30 minutes. The stimulation will target the cymba conchae of the left ear and will consist of alternating 30-second on and 30-second off periods. The current intensity will range from 1 to 3 mA, adjusted to the patient's pain threshold, with a pulse width of 250 μsec and a frequency of 25Hz.
Sham taVNS
DevicePatients will receive sham taVNS for 15 consecutive days, with each session lasting 30 minutes. The stimulation will target the cymba conchae of the left ear and will consist of alternating 30-second on and 30-second off periods. The current intensity will be fixed at 100 µA, with a pulse width of 250 μsec and a frequency of 25 Hz.
Effects of taVNS on symptom severity in patients with PPCS
The investigators will evaluate the effects of taVNS on the severity of PPCS, as measured by the Rivermead Post-Concussion Questionnaire (RPQ). The RPQ consists of 16 items scored on a 5-point Likert scale (0 = not experienced at all, 4 = severe problem). Total scores range from 0 to 64, with higher scores indicating worse symptom severity. The RPQ will be administered at four time points: baseline, mid-treatment, post-intervention, and one-month follow-up.
Effects of taVNS on brain activity in patients with PPCS
The investigators will assess the effects of taVNS on brain activity using electroencephalography (EEG). Specific metrics analyzed will include: * Power spectral density across frequency bands: delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), and gamma (30-45 Hz). * Functional connectivity patterns across cortical regions based on EEG coherence or phase-locking value. These parameters will be extracted from EEG data collected before and after the first and final taVNS sessions.
Effects of taVNS on cognitive functions in patients with PPCS
Cognitive performance will be assessed using the Test of Attentional Performance (TAP v2.3.1). Individual domain scores will be reported according to test-specific metrics. This assessment will be performed at baseline and after the intervention.
Effects of taVNS on verbal memory in patients with PPCS
The Rey Auditory Verbal Learning Test (RAVLT) will be performed to evaluate verbal memory. This test will be conducted at baseline and post-intervention. Individual domain scores will be reported. This assessment will be performed at baseline and after the intervention.
Effects of taVNS on heart rate variability in patients with PPCS
The investigators will assess heart rate variability (HRV) using electrocardiogram (ECG) recordings. Heart rate variability measurements will be performed before and after the first and final taVNS sessions.
Effects of taVNS on headaches in patients with PPCS
The Headache Impact Test (HIT-6) will be used to evaluate the severity of headaches. Scores range from 36 to 78, with higher scores indicating worse impact. This questionnaire will be administered at three time points: baseline, post-intervention and at one-month follow-up.
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University of Liege
Lead sponsor
University Hospital Sart Tilman, Liege
Collaborator
