Table 2.
Summary of taVNS studies in DoC patients.
| Studies | Yu et al. (16) | Noé et al. (17) | Hakon et al. (18) |
|---|---|---|---|
| Subjects | 1 UWS | 6 UWS 8 MCS |
3 UWS 2 MCS |
| Age (mean ± SD) | 73 | 40.2 ± 16.1 | Median: 67 Range: 21–80 |
| Etiology | Anoxic: 1 | Traumatic: 7 Anoxic: 4 Vascular: 3 |
Traumatic: 5 |
| Time since injury (mean ± SD) | 50 days | 12.1 ± 6.4 months | Median: 41 days Range: 31–95 days |
| Stim site | Cymba conchae bilat | Left tragus | Cymba conchae |
| Sham | – | – | – |
| Device | Custom | Parasym®CE | NEMOS® |
| Frequency (Hz) | 20 | 20 | 25 |
| Pulse width (μs) | <1,000 | 250 | 250 |
| Intensity (mA) | 4.0–6.0 | 1.5 | 0.5 the first 3 days and 1 afterwards |
| Duration | 30 min twice a day for 4 weeks |
30 min twice a day, 5 days/week for 8 weeks |
4 h daily interval of 30 s on and 30 s off for 8 weeks |
| fMRI findings (3.0T) | Thalamus ↑ PCC/ precuneus ↑ |
– | – |
| Behavioral findings | Baseline CRS-R: 6 CRS-R at 4 weeks: 13 Improvement in motor and oromotor subscales Diagnosis: UWS → MCS |
Responders (showed at least one new sign of consciousness) 0/6 UWS 5/8 MCS Improvement in - motor subscale: 3 patients; - visual subscale: 1 patient - >1 subscale: 1 patient |
Diagnosis/ CRS-R score UWS → EMCS/ 5 → 22 UWS → MCS/ 3 → 6 UWS → UWS/ 2 → 3 MCS → MCS/ 12 → 12 MCS → EMCS/ 10 → 23 |
CRS-R, coma recovery scale-revised; EMCS, emergence of minimal conscious state MCS, minimal conscious state; UWS, unresponsive wakefulness syndrome; fMRI, functional magnetic resonance imaging; Hz, Hertz; mA, milliamperes; μs, microseconds; s, seconds; SD, standard deviation; T, Tesla.