Primoz Strojnik

Micromodular implants to provide electrical stimulation of paralyzed muscles and limbs

Describes the design, fabrication, and output capabilities of a microminiature electrical stimulator that can be injected in or near nerves and muscles. Each single channel microstimulator consists of a cylindrical glass capsule with hermetically sealed electrodes in either end (2-mm diameter/spl times/13-mm overall length). Power and digital control data can be transmitted to multiple implants (256 unique addresses) via a 2-MHz RF field created by an external AM oscillator and inductive coil. In vitro testing demonstrated accurate control of output pulsewidth (3-258 /spl mu/s in 1-/spl mu/s steps) and current (0-30 mA in two linear ranges of 16 steps each, up to 8.5 V available compliance voltage). Microstimulators were used successfully for chronic stimulation in hindlimb muscles of cats. Design and fabrication issues affecting yield and reliability of the packaging and electronics are discussed.

Multichannel cochlear implant system including wearable speech processor

A tissue stimulating system including an external transmitter for transmitting data to an implanted stimulator including a processor for generating stimulation signals for application to a plurality of tissue stimulating electrodes. The processor selectively monitors the electrodes and/or voltages generated in the stimulator and generates stimulator status indicating signals for transmission to the external transmitter. The external processor receives and processes such status indicating signals.

Multichannel FES system with distributed microstimulators

This work describes a newly developed implantable multichannel stimulation system using distnbuted stimulation modules, manufactured in the form of small glass capsules with a stimulating electrode On each end The modules, microstimulators, are powered from an external antenna using a 2 MHz amplitude modulated carrier containing stimulation parameters data. Using 36 bit command strings modules are individually addressed and programmed to deliver a stimulation pulse of a certain amplitude, width, and shape. The repetition rate at which a particular module is addressed represents the stimulation frequency. Up to 256 modules can be addressed and controlled from one external antenna.

Microtelemetry techniques for implantable smart sensors

The advent of the emerging field of smart sensors suggests new applications for implantable microelectronic devices in neural prostheses. Optimal use of miniature and subminiature (thin- film) electronic sensors in implanted systems will depend upon the nature of the power and communication link to the sensor. Microtelemetry technology is under current development to meet this need. Microtelemetry techniques can be used to provide operating power and bi- directional communication for a microimplant through a common, wireless, magnetic link. Owing to the extremely unfavorable geometry, i.e. the size of the implant relative to the size of the extracorporeal transmitter, the design of such links is highly parametric. Magnetic circuit parameters must be closely matched to the implants integrated-circuit power usage. In addition, the bandwidth of the communication channel must be adequate to meet the data collection requirements. This paper describes on-going R&D work for the design and fabrication of smart sensors based upon microtelemetry technology. Presently, sensor designs for two applications are in progress -- EMG and joint angle position.