Restoring arm and hand function after stroke: Vagus nerve stimulation paired with rehabilitation

Key Takeaways

• Deficits from stroke can decrease independence and quality of life.
• Vagus nerve stimulation (VNS) with therapy is a new treatment option that has shown to improve motor skill recovery in patients with weakness in one arm or hand after stroke.
• The device is implanted in the neck, and an external controller is used to trigger stimulation during therapy.
• This treatment has been shown to produce greater improvements in motor control and task performance when compared to conventional therapy.

Stroke often leaves survivors with weakness in an arm or hand that can continue despite treatment. Even small improvements in reaching, grasping, and finger control can dramatically improve a person’s independence and quality of life.  

Recently, a procedure called vagus nerve stimulation (VNS) paired with task-specific rehabilitation therapy is a promising addition to enhance motor recovery for people with chronic and progressive hand or arm weakness after a stroke.  

What is “VNS paired with therapy”? 

VNS involves delivering brief, low-intensity electrical pulses to the vagus nerve, the longest and most complex cranial nerve that connects the brain and internal organs.  

In paired VNS therapy for stroke, each pulse (or short train of pulses) is timed to coincide with a specific, successful movement during rehabilitation exercises (e.g., a reach, grasp, or pinch). 

The goal is to use these precisely timed signals to promote neuroplasticity — strengthening the brain circuits that control the practiced movement — so gains made in therapy carry over into real-world function. 

Devices used for this purpose include an implanted pulse generator with a lead wrapped around the vagus nerve in the neck and an external controller used by the therapist to trigger stimulation during practice. 

How can VNS enhance motor recovery? 

When stimulation is paired precisely with a movement, it increases the likelihood that the neuronal circuits responsible for that movement will be potentiated — essentially strengthening the “wiring” of that behavior. 

Timing is critical: stimulation needs to occur within a narrow window around the movement to effectively open a temporary window in the brain where neural connections can be easily modified and reinforce the correct motor pattern. 

What does therapy look like? 

A stroke rehabilitation team evaluates motor deficits, spasticity, cognition, medical history, and expectations. Imaging and nerve function assessments may be used. 

For implant-based VNS, a small chest implant is placed under general anesthesia with a lead wrapped around vagus nerve in the neck. Recovery from the surgery is typically brief. 

Patients usually engage in intensive, task-specific training sessions (often several times per week) where the therapist triggers brief VNS bursts time-locked to successful repetitions of target movements.  

The protocols used emphasize high-repetition, motivated practice of functional tasks, like reaching, grasping, and manipulation. 

Programs last a few weeks to several months. Improvements are assessed with standardized motor scales and functional measures. 

Who might be a good candidate? 

Individual evaluation is essential, as not all patients will be eligible or appropriate candidates. 

Candidates for VNS with therapy include adults with weakness in just one arm or hand after ischemic stroke who have the cognitive ability to participate meaningfully in repetitive task-oriented training. 

They must be medically fit for a minor surgical implantation and have no contraindications to VNS, including certain heart arrhythmia or other implants that may be incompatible with the VNS implant. 

What are the benefits? 

The therapy increases gains from conventional therapy, often producing greater improvements than therapy alone. 

It can improve both impairment (motor control) and function (task performance). 

The effects may last beyond the stimulation period when paired with intensive, task-focused training. 

Conclusion  

VNS paired with targeted, repetitive rehabilitation is an exciting, evidence-backed approach to enhancing upper limb recovery after stroke.  

When delivered in experienced centers to appropriately selected patients and combined with intensive task-specific practice, it can produce meaningful improvements in arm and hand function that translate into better daily living.  

As research advances and access grows, VNS-paired therapy may become an important component of stroke rehabilitation. 

For more information on the WVU Rockefeller Neuroscience Institute, visit WVUMedicine.org/RNI.