Transcutaneous Auricular Vagus Nerve Stimulation Modulates the Prefrontal Cortex in Chronic Insomnia Patients: fMRI Study in the First Session

Abstract

ObjectivesTranscutaneous auricular vagus nerve stimulation (taVNS) has been reported to be effective for chronic insomnia (CI). However, the appropriate population for taVNS to treat insomnia is unclear.MethodsTotal twenty-four patients with CI and eighteen health controls (HC) were recruited. Rest-state functional magnetic resonance imaging (Rs-fMRI) was performed before and after 30 min' taVNS at baseline. The activated and deactivated brain regions were revealed by different voxel-based analyses, then the seed-voxel functional connectivity analysis was calculated. In the CI group, 30 min of taVNS were applied twice daily for 4 weeks. Pittsburgh Sleep Quality Index (PSQI) and Flinders Fatigue Scale (FFS) were also assessed before and after 4 weeks of treatment in the CI group. The HC group did not receive any treatment. The correlations were estimated between the clinical scales' score and the brain changes.ResultsThe scores of PSQI (p < 0.01) and FFS (p < 0.05) decreased after 4 weeks in the CI group. Compared to the HC group, the first taVNS session up-regulated left dorsolateral prefrontal cortex (dlPFC) and decreased the functional connectivity (FCs) between dlPFC and bilateral medial prefrontal cortex in the CI group. The CI groups' baseline voxel wised fMRI value in the dlPFC were negatively correlated to the PSQI and the FFS score after 4 weeks treatment.ConclusionsIt manifests that taVNS has a modulatory effect on the prefrontal cortex in patients with CI. The initial state of dlPFC may predict the efficacy for taVNS on CI.

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“…Correspondingly, the present review suggested that acupuncture could modulate a wide range of FPN regions, including SFG, mPFC, MFG. Acupuncture has been extensively explored for its capacity to alleviate pain by modifying the dysfunctional DLPFC (He et al, 2022 ; Liu et al, 2022 ; Zhang et al, 2022 ). Consequencely, Ong's team revealed the importance of PFC during placebo analgesia and in establishing a connection between pain and pain alleviation in bouts of cognitive performance, anxiety, and cognitive decline (Ong et al, 2019 ).…”

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“…In summary, although various studies using a pre–post design without a control condition report strong effects of taVNS on insomnia symptoms (He et al, 2022 ; Wu et al, 2021 ; Zhang et al, 2021 ), current evidence from sham‐controlled trials does not indicate substantial effects of taVNS on improving insomnia symptoms.…”

Therapeutic applications of transcutaneous auricular vagus nerve stimulation with potential for application in neurodevelopmental or other pediatric disorders

“…A possible explanation is that they share some diagnostic symptoms, such as sleeping problems, difficulty concentrating, being easily fatigued, and psychomotor agitation ( 144 ). It has been reported that taVNS treatment is effective in improving sleep quality and prolonging sleep duration in primary insomnia patients via the regulation of a broad brain network (i.e., default mode network, salience network and sensorimotor network) ( 96 , 97 , 145 , 146 ). He and colleagues ( 97 ) have also reported that 4 weeks of taVNS treatment improved chronic insomnia symptoms by decreasing Pittsburgh Sleep Quality Index (PSQI) and Flinders Fatigue Scale (FFS) scores, and increasing the reduced neuroexcitability of the dorsolateral prefrontal cortex.…”

“…It has been reported that taVNS treatment is effective in improving sleep quality and prolonging sleep duration in primary insomnia patients via the regulation of a broad brain network (i.e., default mode network, salience network and sensorimotor network) ( 96 , 97 , 145 , 146 ). He and colleagues ( 97 ) have also reported that 4 weeks of taVNS treatment improved chronic insomnia symptoms by decreasing Pittsburgh Sleep Quality Index (PSQI) and Flinders Fatigue Scale (FFS) scores, and increasing the reduced neuroexcitability of the dorsolateral prefrontal cortex. Altered dorsolateral prefrontal cortex excitability was associated with symptom improvements and may therefore predict the efficacy of taVNS treatment effects.…”