Web technology based microelectrode characterization instrument.

In order to track the on-going changes and ultimate reliability of neural recording and stimulation arrays, it is beneficial to regularly characterize electrode arrays within the use environment. Microelectrodes used for neural stimulation or recording research can have different behaviors in-vivo vs. in- vitro, and once implanted the success of the experiment often hinges upon knowing the stability, changes, or deterioration of the electrodes.

Multichannel wireless ECoG array ASIC devices.

Surgical resection of epileptogenic foci is often a beneficial treatment for patients suffering debilitating seizures arising from intractable epilepsy [1], [2], [3]. Electrodes placed subdurally on the surface of the brain in the form of an ECoG array is one of the multiple methods for localizing epileptogenic zones for the purpose of defining the region for surgical resection. Currently, transcutaneous wires from ECoG grids limit the duration of time that implanted grids can be used for diagnosis.

Low-power polling mode of the next-generation IMES2 implantable wireless EMG sensor.

The IMES1 Implantable MyoElectric Sensor device is currently in human clinical trials led by the Alfred Mann Foundation. The IMES is implanted in a residual limb and is powered wirelessly using a magnetic field. EMG signals resulting from the amputee's voluntary movement are amplified and transmitted wirelessly by the IMES to an external controller which controls movement of an external motorized prosthesis.

A laboratory instrument for characterizing multiple microelectrodes.

The task of chronic monitoring and characterizing a large number of microelectrodes can be tedious and error prone, especially if needed to be done in vivo. This paper presents a lab instrument that automates the measurement and data processing, allowing for large numbers of electrodes to be characterized within a short time period. A version 1.

Intrinsic activation of iridium electrodes over a wireless link.

Activated Iridium Oxide Film (AIROF) microelectrodes are regarded as advantage for stimulation of neural tissue owing to their superior charge injection capabilities, as compared to other noble-metal based electrodes. Including AIROF electrodes within an implantable neural stimulator can be challenging since the stimulator fabrication steps often involve elevated temperatures at which the AIROF can be damaged. In this work, a wireless neural stimulator application-specific-integrated-circuit (ASIC) was used to intrinsically activate iridium microelectrodes.

An implantable neural stimulator for intraspinal microstimulation.

This paper reports on a wireless stimulator device for use in animal experiments as part of an ongoing investigation into intraspinal stimulation (ISMS) for restoration of walking in humans with spinal cord injury. The principle behind using ISMS is the activation of residual motor-control neural networks within the spinal cord ventral horn below the level of lesion following a spinal cord injury. The attractiveness to this technique is that a small number of electrodes can be used to induce bilateral walking patterns in the lower limbs.

Decoding individuated finger flexions with Implantable MyoElectric Sensors.

We trained a rhesus monkey to perform randomly cued, individuated finger flexions of the thumb, index, and middle finger. Nine Implantable MyoElectric Sensors (IMES) were then surgically implanted into the finger muscles of the monkey's forearm, without any observable adverse chronic effects. Using an inductive link, we wirelessly recorded EMG from the IMES as the monkey performed a finger flexion task.

A monolithic multi-channel amplifier for electrode arrays.

We present a monolithic microelectronic multichannel amplifier designed to facilitate measurements from multi-electrode arrays. A single silicon chip includes sixteen electrode amplifiers, along with interface and control circuitry to allow data collection through a compact 4-wire interface.

An implantable myoelectric sensor based prosthesis control system.

We present progress on the design and testing of an upper-extremity prosthesis control system based on implantable myoelectric sensors. The implant consists of a single silicon chip packaged with transmit and receive coils. Forward control telemetry to, and reverse EMG data telemetry from multiple implants has been demonstrated.

Technical Details of the Implantable Myoelectric Sensor (IMES) System for Multifunction Prosthesis Control.

The limitation of current prostheses is not the devices themselves but rather the lack of sufficient independent control sources. A system capable of reading intra muscular EMG signals would greatly increase the number control sources available for prosthesis control. We are developing a multichannel/multifunction prosthetic hand/arm controller system capable of receiving and processing signals from up to sixteen implanted bipolar differential electromyographic (EMG) electrodes.