The g.Estim FES is a constant-current, biphasic electrical stimulator and is intended for temporary reduction of muscle spasms, prevention or retardation of disuse atrophy, increasing local blood flow in the treatment area, muscle re-education, prevention of post-surgical phlebo-thrombosis through immediate stimulation of calf muscles, and maintaining or increasing range of motion.
g.Estim FES has an applied part of type BF with connectors for bipolar stimulation electrodes (anode and cathode). The device is controlled by a computer via an USB connection. It also has digital outputs for synchronization with other devices. An optional hand-switch allows you to perform stimulation manually. Alternatively, an optional foot-switch can be used to explicitly enable/disable stimulation. g.Estim FES includes an impedance measurement function and contains a high-impedance stop mechanism that stops stimulation when electrode contact becomes loose.
For closed-loop experiments, g.USBamp, g.HIamp or g.Nautilus with g.HIsys is used to record EEG/ECoG data, perform real-time analysis and to control the g.Estim FES for muscle or nerve stimulation.
|Delivers bi-phasic constant current pulses|
|Stand-alone device that can be controlled from a computer system|
|Can send triggers to other devices for synchronization|
|Includes electrode impedance check and stimulation current monitoring|
|CE-certified and FDA-cleared medical device for use in human|
|Stimulus current output||± 1 – 60 mA (±10%)|
|Work time||2 - 20 s in 0.5 s increments (± 10 % accuracy)|
|Rest time||2 - 50 s in 0.5 s increments (± 10 % accuracy)|
|Phase duration||50 µs - 400 µs in 10 µs increments (± 10 % or ± 10 µs whichever greater)|
|Pulse rate||1 – 100 pulses/second in 1 pulse increments (±10%) (Pulse period from 1 s down to 10 ms)|
|Rising/falling ramps||0 - 10 s in 0.5 s increments (± 5 % accuracy)|
|Power supply||2 x 9 V battery, USB – connection|
|Certification and Standards||IEC 60601-1, IEC 60601-1-2, IEC 60601-2-10, IEC 62304, IEC 62366, ISO 14971|
The hand switch is an accessory of the g.Estim FES. Users connect the hand switch to the hand/foot switch input of the g.Estim FES. The hand switch allows them to start stimulation by pressing the blue STIMULATE button after the device has been set active via the software and the ‘active’ LED is on. During stimulation, the hand switch allows users to abort stimulation by pressing the grey ABORT button.
The foot switch is another accessory of the g.Estim FES and can be connected to the hand/foot switch input of the g.Estim FES. When the foot switch is used and pressed, the stimulator accepts a cue to start stimulation from the software or from devices connected to the digital input ports. When the foot switch is released, stimulation is aborted.
g.ESTIM FES SIMULINK INTERFACE
The g.Estim FES Simulink Interface allows you to set all required parameters of the FES stimulator and to trigger the stimulator from Simulink. Importantly, the stimulator also measures the stimulation current to confirm that the actual current can be delivered (depending on the electrode impedance). The g.Estim FES Simulink Interface provides a graphical interface to the g.Estim FES hardware, which can be used under Simulink to specify the properties of the electrical stimulator. The Simulink block allows you to specify the Phase Duration, the Phase Amplitude in real-time or via a graphical user interface and allows to start and stop the stimulation. The block provides the state (on/off), the battery level, the Max. Phase Duration and the Max. Phase Amplitude to the user. Use the FES Control Panel to manually set the stimulation parameters and to start and stop the stimulation. The applied charge density is also visualized in the window.
SPINAL CORD INJURY
The g.Estim FES may be indicated for muscle stimulation when muscles that are partly or fully paralyzed due to central nervous system injury should be contracted to generate movement, such as in patients with spinal cord injury. The BCI system can be used to detect the patient’s motor imagery and can trigger the FES to produce the required hand movement. In 2016, Gaurav Sharma from Battelle Memorial Institute in Ohio (USA) won the BCI Award 2016 with his project about an implanted BCI for real-time cortical control of wrist and finger movements.
Functional electrical stimulation (FES) can trigger movements of different areas of the body. After a doctor or therapist mounts stimulation electrodes over the corresponding muscle or muscle group, the FES system can send a current through the muscles to initiate movement. This technique can be applied in stroke patients or spinal cord injury patients to reduce spasticity and help encourage movement.
FES electrodes are fixed on the position where the muscle should be stimulated.
“We use the g.Estim FES in our research study involving stroke patients with upper extremity deficits. It is a solid and reliable system that is easy to use in our research.”Vivek Prabhakaran, MD, PhD - University of Wisconsin-Madison, USA