Transcutaneous auricular vagus nerve stimulation with task-oriented training improves upper extremity function in...

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Biomedical Engineering

Background:

• Transcutaneous auricular vagus nerve stimulation (taVNS) is a promising non-invasive brain stimulation technique for post-stroke upper extremity rehabilitation.
• The precise mechanisms by which taVNS facilitates motor recovery in stroke patients are not fully understood.

Purpose of the Study:

• To investigate the efficacy of taVNS combined with task-oriented training (TOT) for improving upper extremity function in patients with subacute stroke.
• To explore the underlying neurophysiological mechanisms of motor recovery associated with this combined intervention.

Main Methods:

• A double-blinded, randomized, controlled pilot trial involving 40 subacute stroke patients.
• Participants were assigned to either taVNS during TOT or sham taVNS during TOT for 4 weeks, 5 days/week.
• Outcome measures included upper extremity function (FMA-UE, ARAT), activities of daily living (MBI), cortical excitability (MEPs), and brain activity (fNIRS).

Main Results:

• The taVNS group showed significant improvements in upper extremity function and activities of daily living compared to the sham group.
• taVNS enhanced cortical excitability, evidenced by a higher rate of ipsilesional motor-evoked potentials (MEPs) and shorter latency of contralesional MEPs.
• Functional near-infrared spectroscopy (fNIRS) indicated increased activation in the contralesional prefrontal and ipsilesional sensorimotor cortex in the taVNS group.

Conclusions:

• Combining taVNS with TOT is an effective strategy for improving upper extremity function in patients with subacute stroke.
• The intervention likely facilitates functional recovery by modulating bilateral cortical excitability, supporting task-specific motor gains.