Transcutaneous vagal nerve stimulation to treat disorders of consciousness: Protocol for a double-blind randomized controlled trial

Transcutaneous auricular vagus nerve stimulation in the treatment of disorders of consciousness: mechanisms and applications

“…Four studies adopted a frequency of 20 Hz ( Yu et al, 2017 , 2021 ; Yifei et al, 2022 ; Zhou et al, 2023 ). On the other hand, four other studies each utilized a slightly higher frequency of 25 Hz ( Hakon et al, 2020 ; Noé et al, 2020 ; Osińska et al, 2022 ; Vitello et al, 2023 ). The convergence around the 20 Hz to 25 Hz range indicates a potential sweet spot in frequency parameters for taVNS, yet the nuances of these choices underscore the continued efforts to fine-tune the therapy for optimal results.…”

“…When considering taVNS parameter settings for the treatment of DOC, different studies have chosen varied pulse widths. One study used a pulse width of 200us ( Zhou et al, 2023 ), aligning with the lower range of another that ranged from 200 to 300us ( Vitello et al, 2023 ). Three other studies standardized their pulse width at 250us ( Hakon et al, 2020 ; Noé et al, 2020 ; Osińska et al, 2022 ).…”

“…In taVNS studies for DOC treatment, one used a single-phase square wave ( Osińska et al, 2022 ), while another adopted a sinusoidal waveform ( Noé et al, 2020 ). Notably, several other studies did not specify their choice of waveform, suggesting that device-specific waveforms may have been used in these instances ( Yu et al, 2017 , 2021 ; Hakon et al, 2020 ; Yifei et al, 2022 ; Vitello et al, 2023 ; Zhou et al, 2023 ). The variations and omissions in waveform descriptions underscore the need for more standardized reporting in future research to fully understand the potential nuances and effects of different waveforms in taVNS treatment.…”

“…Considerable evidence has suggested that taVNS is a therapeutic intervention for various neurological and psychiatric conditions, such as epilepsy ( Thompson et al, 2021 ), depression ( Liu et al, 2020 ), and migraine ( Zhang et al, 2021 ). Regarding DOC, taVNS has the potential to modulate thalamo-cortical connectivity and neurotransmitter systems ( Vitello et al, 2023 ), which are critical for promoting awareness and arousal. As a non-invasive method, taVNS avoids the risks associated with invasive procedures and offers a more focused approach to modulating key brain networks involved in consciousness, characterized by its bottom-up neural transmission pathway, when compared to other non-invasive stimulation techniques like TMS and tDCS ( Wu et al, 2021 ).…”

Unlocking consciousness through right median nerve stimulation. Has a potential cure arrived at our doorstep?

“…Peripheral electrical nerve stimulation to enhance central nervous system neuroplasticity and thereby arousal and emergence from coma has shown clear potential. For instance, transcutaneous auricular vagal nerve stimulation is currently being explored as one such therapy [ 2 ]. Its purported benefit has been linked to enhanced arousal in disorders of consciousness, such as minimal conscious state (MCS) and unresponsive wakefulness syndrome (UWS), with improved connectivity of thalamo-cortical and -prefrontal brain circuits.…”