Table 1.
Summary of studies on transcutaneous auricular vagus nerve stimulation in disorders of consciousness.
| Publication | Patients no. | Brain pathology | taVNS device | Stimulation side and site | Stimulation parameter | Data cycle | Clinical results | Side effect | Brain evaluation | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hz | Pulse width (us) | Intensity (mA) | Min/session | Time/d | Period | ||||||||
| Yu et al[23] (2017) |
1 | Anoxia | NC | Bilateral cymba conchae | 20 | 1000 | 4~6 | 30 | 2 | 50 days | CRS-R: 6→13 | NC | fMRI: DMN connectivity↑ |
| Noé et al[36] (2020) | 14 | TBI: 7 Anoxia: 4 Hemorrhage: 3 |
Parasym® | Left tragus | 20 | 250 | 1.5 | 30 | 2 | 4 weeks | 5 of 8 MCS patients: CRS-R↑ | None | - |
| Hakon et al[37] (2020) | 5 | TBI | Nemos® | Left cymba conchae | 25 | 250 | 0.5~1 | 240 | 1 | 8 weeks | All MCS (2)→emerged from MCS 1 of 3 VS→MCS |
Intermittent itching of the ear (1 patient) | - |
| Yu et al[28] (2021) |
10 | Anoxia: 5 Hemorrhage: 3 TBI: 2 |
NC | Cymba conchae | 20 | 500 | 4~6 | 30 | 2 | 4 weeks | Responded to auditory stimuli (5): CRS-R↑& favorable outcome |
NC | fMRI: Auditory responded group: CBF↑of multiple brain regions |
| Osińska et al[33] (2022) |
1 | TBI | Nemos® | Cymba conchae | 25 | 250 | 0.2→1.5 | 30 | 2 | 6 months | CRS-R: 4~6→8~13 | NC | EEG: alpha range↑ |
| Yifei et al[35] (2022) | 12 | Stroke: 8 Anoxia: 2 TBI: 2 |
Huatuo electronic acupuncture | Bilateral cymba conchae | 20 | 1000> | 4~6 | 30 | 2 | 14 days | CRS-R: no change | NC | EEG: MCS patients in taVNS group: Delta band↑ and Beta band↓ |
CBF: cerebral blood flow, CRS-R: Coma Recovery Scale-Revised, EEG: electroencephalography, fMRI: functional magnetic resonance imaging, DMN: default mode network, MCS: minimally consciousness state, NC: not commented, TBI: traumatic brain injury, taVNS: transcutaneous auricular vagus nerve stimulation, VS: vegetative state.