From the Guidelines
The recommended approach to vagus nerve stimulation (VNS) post chronic stroke is not explicitly supported by the provided evidence, but based on the most recent and highest quality study, there is insufficient evidence to recommend for or against non-invasive brain stimulation, including VNS, for patients in stroke rehabilitation 1. However, the study suggests that non-invasive brain stimulation, such as repetitive transcranial magnetic stimulation, may be considered as an adjunct to upper extremity therapy for stroke survivors 1. The standard protocol for VNS typically involves delivering mild electrical stimulation during rehabilitation sessions, which usually occur 3-5 times weekly for 6-12 weeks. Each session lasts approximately 1-2 hours, with stimulation delivered in 0.5-second bursts timed precisely with therapeutic movements or tasks. This approach requires collaboration between rehabilitation specialists and neurologists to customize the therapy to the patient's specific deficits. Some key points to consider when implementing VNS post chronic stroke include:
- The importance of individualized treatment plans, taking into account the patient's specific deficits and needs.
- The potential benefits of combining VNS with other rehabilitation therapies, such as physical therapy, occupational therapy, and speech therapy.
- The need for ongoing monitoring and evaluation to assess the effectiveness of VNS and make adjustments to the treatment plan as needed.
- The potential risks and side effects of VNS, such as skin irritation, headache, and fatigue, and the importance of carefully weighing these against the potential benefits. It is essential to note that VNS is typically considered after conventional rehabilitation approaches have plateaued, and outcomes vary based on stroke severity, location, and time since onset. Additionally, the evidence suggests that exercise, including aerobic exercise, resistance training, and flexibility exercises, is beneficial for stroke survivors and can be used in conjunction with VNS 1. Overall, while the evidence for VNS post chronic stroke is limited, it may be considered as part of a comprehensive rehabilitation plan, and further research is needed to fully understand its potential benefits and risks.
From the Research
Vagus Nerve Stimulation Post Chronic Stroke
The recommended approach to vagus nerve stimulation (VNS) post chronic stroke involves both invasive and non-invasive methods.
- Invasive VNS paired with rehabilitation has been shown to improve upper limb motor function in chronic stroke patients 2.
- Non-invasive VNS, including transcutaneous VNS (tVNS) and auricular VNS, has been found to activate similar vagal nerve projections in the central nervous system to invasive VNS and may improve upper limb motor and sensory function in patients with chronic stroke 3, 4.
Mechanisms and Effects
The mechanisms of VNS in stroke include:
- Anti-inflammatory effects
- Reduced excitotoxicity
- Increased blood-brain barrier integrity
- Microglial polarisation
- Angiogenesis
- Neurogenesis These effects may mediate neuroplasticity and improve recovery after stroke 3, 5.
Therapeutic Implications
VNS has been found to be a promising therapeutic technique for the treatment of stroke, with potential applications in both acute and chronic stroke 4, 5, 6.
- VNS paired with rehabilitation has been shown to be safe and feasible in patients with upper limb motor deficit after chronic ischemic stroke 2.
- Non-invasive VNS may be a promising alternative for improving muscle function in chronic stroke patients 4.
Future Directions
Further research is needed to fully understand the mechanisms of VNS in stroke and to determine its efficacy in larger clinical trials 3, 4, 6.