NuStim is a novel, inductively-powered and -controlled microstimulator for the chronic electrical stimulation. It is small enough (3 mm diameter x 10 mm long) to be implanted percutaneously into a muscle and close to motor axons via a simple insertion tool consisting of a dilator and sheath.
The NuStim microstimulators can be externally controlled to produce a wide range of charge-controlled stimulus intensities that is expected to be sufficient to assure complete recruitment of the motor units in that muscle. Various exercise parameters are prescribed by the doctor and sent from an Android app to the external RF-cushion via BLE communication. In order to receive muscle stimulation, the subject must be sitting on the RF-cushion, thereby positioning the inductive coil in the cushion in correct alignment with the implanted NuStim. For each stimulus output pulse, the RF-cushion transmits a burst of RF energy for a precisely controlled duration that controls the amount of charge that the NuStim delivers at the end of the RF burstThe NuStim output is charge-balanced, capacitively coupled with a cathodal stimulus phase that has a time-constant of approximately 0.33 ms duration .During each exercise cycle at the selected repetition rate, the pulse intensity ramps up from threshold to the selected intensity step, holds at that level, and then ramps down, followed by a pause between cycles. These cycle parameters will default to our initially recommended values, but will be left adjustable over wide ranges in the first stages of clinical trials.