Stroke Technology

A Therapy Grounded in Neuroscience Research

MicroTransponder’s approach to treating stroke is based on extensive scientific research. This innovative approach pairs a well-known treatment called vagus nerve stimulation (VNS) with traditional rehabilitative exercises. This new method is known as Paired Vagus Nerve Stimulation or Paired VNS™. It should be noted that traditional VNS has been used in the U.S. and around the world to treat over 100,000 patients for epilepsy.

The Vivistim® System stimulates the vagus nerve while the patient is undergoing a rehabilitative movement, which tells the brain to “pay attention” to that movement. This simultaneous pairing of a specific movement with vagus nerve stimulation (VNS) strengthens motor circuits associated with the physical movement. Consistently pairing VNS with specific neural circuits helps rebuild those circuits and the brain relearns the commands to enable the muscles to perform specific tasks and can strengthen those muscles as well. This simultaneous pairing of muscle movement with VNS strengthens the neural circuits in the brain. Over time, a patient may regain upper limb function. The neuroscience research team has published studies in several academic journals, including the American Heart Association journal Stroke in January of 2016. (Source)

The Therapy in Action

The image below illustrates the therapy in action. While the patient is performing a rehabilitative exercise, the physical therapist pushes a button, which triggers the wireless transmitter to send a signal to the implanted device to deliver a small burst of electrical stimulation to the vagus nerve.

 

Mechanism of Action of Paired VNS™

1

Vagus Nerve Stimulated

Implanted lead delivers bursts of electricity that travel up to the brain.

2

Electric Signal Reaches the Brain

The electric signal passes through the Nucleus Tractus Solitarius (NTS) to 2 distinct brain regions. When these regions receive the electric signal, they release neuromodulators (brain chemicals).

3

Neurotransmitters Disperse Throughout

The release of transmitters increases the relevance of the physical therapy. The resulting brain reorganization and strengthening of the neural connections contributes to the enhanced motor function. These neuromodulators are important for learning and memory and help increase the salience (or relevance) of the physical therapy.

Sources: Kilgard, MP Science. 1998 Mar 13;279(5357):1714-8, Engineer, ND Nature. 2011 Feb 3;470(7332):101-4.

Our Approach

Each time the vagus nerve is stimulated, it sends a signal up to the brain, which triggers the release of neurotransmitters broadly across the brain including the motor cortex, thus enabling neuroplasticity to increase motor function.

Components of the Vivistim® System

The Vivistim® System includes 4 main components

 

Model 1000 Paired VNS™ Implantable Pulse Generator

  • Size:

    48 mm wide x 62 mm tall x 12 mm thick

  • Weight:

    Less than 70g

  • Power Source:

    U CfX – Lithium/Carbon Monofluoride

  • Output Current:

    0 to 3.5 mA

  • Frequency:

    1 to 30 Hz

  • Pulse Width:

    10 μs to 1000 μs

  • Output:

    Bipolar output

 

Model 3000 Paired VNS™ Lead

  • Total Length:

    43 cm

  • Outer Material (insulation):

    Silicone

  • Lead Body Diameter:

    2mm

  • Resistance:

    100 – 250 Ohms

  • Cuff Diameter:

    2mm or 3mm

 

Model 4000 Paired VNS™ Stroke Application and Programming Software (SAPS)

The SAPS software is loaded onto a laptop computer used by the physical therapist along with a push button controller which is held by the physical therapist during the rehabilitative exercises.

 

Model 2000 Paired VNS™ Wireless Transmitter

1. Engineer Navzer, Riley Jonathan, Seale Jonathan, Vrana Will, Shetake Jai, Sudanagunta Sindu, Borland Michael, and Kilgard Michael, “Reversing pathological neural activity using targeted plasticity”, Nature, vol. 470, pp. 101-104, January 2011

2. Kilgard MP1, Merzenich MM, “Cortical map reorganization enabled by nucleus basalis activity”, Science. 1998 Mar 13;279(5357):1714-8.

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