Consciousness disorders following severe brain injury refer to a series of disturbances in arousal and cognition secondary to organic brain diseases, including Unresponsive Wakefulness Syndrome (UWS) (also termed Vegetative State, VS) and Minimally Conscious State (MCS). DoC is listed in the International Statistical Classification of Diseases and Related Health Problems, though it is not currently recognized as an independent and consistent diagnostic category. According to epidemiological surveys, conservative estimates suggest that 70,000 to 100,000 new cases of DoC are reported annually in China, posing significant challenges for clinical diagnosis and treatment. Accurately assessing DoC, understanding its neurobiological underpinnings, and developing effective rehabilitation strategies remain subjects requiring further investigation through both clinical and basic neuroscience research. Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) is a non-invasive brain stimulation technique that delivers electrical impulses to the auricular branch of the vagus nerve. Substantial evidence indicates that taVNS serves as a therapeutic intervention for various neurological and psychiatric disorders, such as epilepsy, treatment-resistant depression, migraines, and cognitive impairments. As an emerging neurostimulation technique, taVNS has been investigated for its potential to promote the recovery of awareness in patients with DoC. However, clinical evidence remains limited, underscoring the need for further trials to substantiate its efficacy. Developed from traditional implanted VNS, taVNS offers high safety and minimal to negligible side effects, presenting a promising therapeutic avenue for patients with severe traumatic brain injury and disorders of consciousness. Methods: This study is a single-arm trial. A total of 20 patients are planned to be enrolled. Each patient will receive transcutaneous auricular vagus nerve stimulation (taVNS) twice daily over a period of 10 consecutive days, totaling 20 sessions. Primary and secondary outcome measures will be assessed at baseline and after the completion of taVNS treatment. The primary efficacy endpoint will be the change in behavioral responses as evaluated by the Coma Recovery Scale-Revised (CRS-R). Additionally, resting-state high-density electroencephalography (EEG) and combined transcranial magnetic stimulation with EEG (TMS-EEG) recordings will be utilized to investigate the neurophysiological correlates of taVNS intervention. Discussion: This study will provide valuable insights to inform the selection of treatment approaches for patients with disorders of consciousness. By employing a pre-post within-subject comparison design, it aims to validate the therapeutic role of Closed-Loop Transcutaneous Auricular Vagus Nerve Stimulation (CL-taVNS) in this patient population.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
20
The stimulation protocol consisted of pulse trains at a frequency of 100 Hz. A total of 400 paired RAVANS pulses were delivered per session. The intervention was administered twice daily for 10 consecutive days, resulting in a total of 20 sessions.
Zhujiang Hospital of Southern Medical University
Guangzhou, Guangdong, China
RECRUITINGChange from Baseline JKF Coma Recovery Scale-Revised(CRS-R)
The CRS-R comprises six subscales designed to assess auditory, visual, oromotor, communication,and arousal processes. Each CRS-R subscale score is determined based on the presence or absence of specific behavioral responses to sensory stimuli. The total score ranges from 0 to 23, with higher scores indicating a higher level of consciousness in patients with DoC.
Time frame: immediately after 10 days TaVNS session
Change from Baseline Resting-State EEG
EEG data will be recorded for 10 minutes using a 66-channel cap arranged according to the International 10-20 System. From artifact-free EEG epochs, relative spectral power (RSP) and functional connectivity (FC) will be derived across five frequency bands: δ (1-4 Hz), θ (4-8 Hz), α (8-13 Hz), β (13-30 Hz), and γ (30-45 Hz). All analyses of RSP and FC will be performed offline.
Time frame: immediately after 10 days TaVNS session
Change from Baseline TMS-EEG
Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) is an effective way to measure cortical activity.In this study, PCIst, a derivative version of PCI, PCIst was chosen as an alternative, which estimates the complexity of TMS perturbations by signal decomposition and recurrence quantification analysis (RQA).
Time frame: immediately after 10 days TaVNS session
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