An externally powered, multichannel, implantable stimulator-telemeter for control of paralyzed muscle

Abstract

An implantable integrated stimulator and telemetry system has been developed. The system is capable of fulfilling the stimulus and telemetry needs of advanced functional neuromuscular stimulation (FNS) applications requiring multiple channels of stimulation and multiple channels of sensor or biopotential sensing. This system provides a command control structure, an inductive radio frequency link providing power to the implant device as well as two-way transcutaneous communication, an ASIC for decoding the command and for providing functional control within the implant, and modular circuitry providing the application specific implant functions. Biocompatible hermetic packaging, lead systems, and in-line connectors suitable for long-term implantation, provide encapsulation for the circuitry and access to the electrodes and sensors used in the application. The first implant configuration realized from this modular system is targeted for clinical implementation in persons with tetraplegia at the C6 level for restoration of hand function, using wrist position as the command control source. The implant device realized has ten channels of stimulation and telemetry used to control and sense a joint angle transducer implanted in the radio-carpal joint of the wrist. A prototype device has been fabricated and is undergoing testing in an animal.

Optimal frequencies for inductive powering of fully implantable biosensors for chronic and elderly patients

“…A reduced size of the coils causes a higher optimal frequency, together with a reduced maximum power gain. For the tested geometries, the optimal frequency is located always over 100 MHz, at least one order of magnitude higher than the frequencies commonly used [1][2][3][4][5][6][7][8]. With the largest geometry the link efficiency is about 30%.…”

“…Inductive links are widely used for remote powering of implantable biosensors [1][2][3][4][5][6][7][8] and typically operate at frequencies below 10 MHz. This upper limit is often proposed to minimize the quantity of power absorbed by the tissues and to increase the link efficiency.…”

An objective method for selecting command sources for myoelectrically triggered lower-limb neuroprostheses

“…In this study, we evaluated the ability of both nondisabled volunteers and individuals with iSCI to determine the intent to step during level overground walking using surface electromyogram (EMG). Our goal was to specify a process and criterion for selecting two muscles for a new command and control interface that can be implemented with only two channels of implanted EMG recording electrodes to coincide with the technical capabilities of currently available implantable technology [3][4][5][6]. This article summarizes the method for evaluating the surface EMG from partially paralyzed muscles of two volunteers with iSCI and its comparison with normative data from four nondisabled participants.…”

Design and Optimization of Inductive Power Link for Biomedical Applications

“…Powering biomedical devices is a major issue in the design of wearable and implantable electronics Chaimanonart et al (2006); Chen et al (2009); Kendir et al (2004); Smith et al (2002). Often, there is not space available for a battery that will last for the lifetime of the device, as batteries are limited both by total charge storage ability and number of recharge cycles Heller (2006).…”