Paired vagus nerve stimulation for treatment of upper extremity impairment after stroke

The use of a paired vagus nerve stimulation (VNS) system for the treatment of moderate-to-severe upper extremity motor deficits associated with chronic ischemic stroke has recently been approved by the US Food and Drug Administration. This treatment aims to increase the task-specific neuroplasticity through the activation of cholinergic and noradrenergic networks during rehabilitation therapy. A recent pivotal Phase III trial showed that VNS paired with rehabilitation led to improvements in upper extremity impairment and function in people with moderate-to-severe arm weakness for an average of 3 years after ischemic stroke. The between-group difference following 6 weeks of in-clinic therapy and 90 days of home exercise therapy was three points on the upper extremity Fugl-Meyer score. A clinically meaningful response defined as a greater than or equal to six-point improvement was seen in approximately half of the people treated with VNS compared to approximately a quarter of people treated with rehabilitation alone. Further post-marketing research should aim to establish whether the treatment is also of use for people with intracerebral hemorrhage, in people with more severe arm weakness, and for other post-stroke impairments. In addition, high-quality randomized studies of non-invasive VNS are required.