A custom designed chip to control an implantable stimulator and telemetry system for control of paralyzed muscles.

A custom designed chip has been developed for the control of paralyzed muscles. 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 for sensor or biopotential sensing. An inductive radiofrequency link provides power to the implant device as well as 2 way transcutaneous communication. An application specific integrated circuit (ASIC) decodes the commands and provides functional control within the implant, and modular circuitry provides specific implant functions. The ASIC chip provides up to 32 independent channels of stimulation with independent control of stimulus pulse duration, pulse amplitude, interphase delay, recharge phase duration, and pulse interval. It can also control up to 8 independent back telemetry analog channels with independent control of sampling rate and pulse powering parameters (amplitude and duration). The mixed analog digital chip has been fabricated in 1.2 microm n-well CMOS technology.

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

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.

Implantable functional neuromuscular stimulation in the tetraplegic hand.

Functional neuromuscular stimulation of the upper extremity provides manipulative capacity to persons with high level tetraplegia who have insufficient voluntary muscles available for tendon transfer surgery. We report an enhancement of the technique to include surgical implantation of a multichannel receiver-stimulator, sensory feedback stimulation, and tendon transfers. Tendon transfers were done with spastic, rather than voluntary motors employing standard surgical techniques. The system described has been operational for more than 1 1/2 years.

Functional neuromuscular stimulation neuroprostheses for the tetraplegic hand.

Functional neuromuscular stimulation (FNS) of the C5 and C6 tetraplegic upper extremity has been shown to be a valid clinical tool for restoring controlled movement in the paralyzed hand. The current clinical system consists of a shoulder position transducer controlling an external microprocessor-based stimulator, which excites paralyzed muscle via the peripheral nerve using percutaneous leads or a multichannel, implantable stimulator. Tendon transfer surgery of paralyzed but innervated muscle may augment the neurologically deficient upper extremity by allowing the substitution of stronger motors or the addition of new motors where flaccid paralysis (dennervation) eliminates the usual muscle from a grasp pattern. Sensory feedback in the form of machine state and cognitive information can be provided to the normally innervated C5 dermatome skin by subcutaneous electrodes. C5- and C6-level tetraplegics using FNS can independently perform single-hand manipulative tasks at a level similar to that of subjects with intact C7 roots, although they lack the elbow control.