Effects of Transcutaneous Auricular Vagus Nerve Stimulation Combined with Task-Oriented Training on Upper Limb Function Recovery in Patients with Post-Stroke Fatigue

<bold>Objective</bold>To investigate the effect of transcutaneous auricular vagus nerve stimulation (taVNS) combined with task-oriented training (TOT) on upper limb motor function in patients with post-stroke fatigue (PSF).<bold>Methods</bold>A total of 60 stroke inpatients hospitalized in the Department of Rehabilitation Medicine, Sir Run Run Hospital Affiliated to Nanjing Medical University, from May 2022 to December 2023 were enrolled and randomly divided into experimental group and control group using a random number table method, with 30 patients in each group. Both groups received conventional rehabilitation, including pharmacological treatment, physical therapy, occupational therapy, speech therapy, and acupuncture. The control group additionally underwent task-oriented training for 30 minutes per session, once daily, five days a week, for four weeks. The experimental group received the same task-oriented training combined with simultaneous taVNS, targeting the left cymba conchae with a stimulation current perceptible but non-painful, with 30 minutes per session, once a day, 5 days a week, for a total of 4 weeks. Before and after 4 weeks of treatment, the Fugl-Meyer Assessment of Upper Extremity (FMA-UE) and Action Research Arm Test (ARAT) were used to evaluate the patients' upper limb motor function; the Fatigue Severity Scale (FSS) was used to assess the severity of fatigue in patients; the Barthel Index (BI) was used to evaluate patients' activities of daily living; and functional near-infrared spectroscopy (fNIRS) was employed to analyze the resting state functional connectivity of different brain regions.<bold>Results</bold>Before treatment, there was no statistically significant difference in FMA-UE and ARAT scores between the two groups (<italic>P</italic>&gt;0.05). After treatment, both groups showed improvements in FMA-UE and ARAT scores (<italic>P</italic>&lt;0.05). Compared with the control group, the experimental group showed greater improvement in FMA-UE (<italic>P</italic>&lt;0.05), while there was no statistically significant difference in the ARAT score between the two groups (<italic>P</italic>&gt;0.05). Before treatment, there was no statistically significant difference in the FSS score between the two groups (<italic>P</italic>&gt;0.05). The FSS scores decreased in both groups after treatment (<italic>P</italic>&lt;0.05), with a greater reduction in the experimental group (<italic>P</italic>&lt;0.05). Before treatment, there was no statistically significant difference in the BI score between the two groups (<italic>P</italic>&gt;0.05). The BI scores increased significantly in both groups after treatment (<italic>P</italic>&lt;0.05), with the experimental group showing a greater increase (<italic>P</italic>&lt;0.05). After treatment, the results of resting-state functional connectivity values showed that, compared with the control group, the functional connectivity between the ipsilateral premotor and supplementary motor area (ipSMA) and the contralateral dorsolateral prefrontal cortex (cDLPFC), contralateral ventrolateral prefrontal cortex (cVLPFC) and ipsilateral orbitofrontal cortex (iOFC) in the experimental group was enhanced (<italic>P</italic>&lt;0.05). Compared with the control group, the functional connectivity between the ipsilateral sensorimotor cortex (iSMC) and iOFC in the experimental group was enhanced (<italic>P</italic>&lt;0.05).<bold>Conclusion</bold>taVNS combined with TOT can more effectively improve upper limb function in patients with PSF, and promote functional reorganization of the brain by enhancing activation of sensorimotor cortices and strengthening interregional connectivity.