Assessing the manufacturable 32-channel cochlear electrode array: evaluation results for clinical trials.

Reliability evaluation results of a manufacturable 32-channel cochlear electrode array are reported in this paper. Applying automated laser micro-machining process and a layer-by-layer silicone deposition scheme, authors developed the manufacturing methods of the electrode array for fine patterning and mass production. The developed electrode array has been verified through the requirements specified by the ISO Standard 14708-7.

Fabrication of Planar Microelectrode Array Using Laser-Patterned ITO and SU-8.

For several decades, microelectrode array (MEA) has been a powerful tool for in vitro neural electrophysiology because it provides a unique approach for monitoring the activity of a number of neurons over time. Due to the various applications of MEAs with different types of cells and tissues, there is an increasing need to customize the electrode designs. However, the fabrication of conventional MEAs requires several microfabrication procedures of deposition, etching, and photolithography.

Manufacturable 32-Channel Cochlear Electrode Array and Preliminary Assessment of Its Feasibility for Clinical Use.

(1) Background: In this study, we introduce a manufacturable 32-channel cochlear electrode array. In contrast to conventional cochlear electrode arrays manufactured by manual processes that consist of electrode-wire welding, the placement of each electrode, and silicone molding over wired structures, the proposed cochlear electrode array is manufactured by semi-automated laser micro-structuring and a mass-produced layer-by-layer silicone deposition scheme similar to the semiconductor fabrication process. (2) Methods: The proposed 32-channel electrode array has 32 electrode contacts with a length of 24 mm and 0.

Fabrication and evaluation of an improved polymer-based cochlear electrode array for atraumatic insertion.

An atraumatic cochlear electrode array has become indispensable to high-performance cochlear implants such as electric acoustic stimulation (EAS), wherein the preservation of residual hearing is significant. For an atraumatic implantation, we propose and demonstrate a new improved design of a cochlear electrode array based on liquid crystal polymer (LCP), which can be fabricated by precise batch processes and a thermal lamination process, in contrast to conventional wire-based cochlear electrode arrays. Using a thin-film process of LCP-film-mounted silicon wafer and thermal press lamination, we devise a multi-layered structure with variable layers of LCP films to achieve a sufficient degree of basal rigidity and a flexible tip.

A miniaturized, eye-conformable, and long-term reliable retinal prosthesis using monolithic fabrication of liquid crystal polymer (LCP).

A novel retinal prosthetic device was developed using biocompatible liquid crystal polymer (LCP) to address the problems associated with conventional metal- and polymer-based devices: the hermetic metal package is bulky, heavy, and labor-intensive, whereas a thin, flexible, and MEMS-compatible polymer-based system is not durable enough for chronic implantation. Exploiting the advantageous properties of LCP such as a low moisture absorption rate, thermobonding, and thermoforming, we fabricate a small, light-weight, long-term reliable retinal prosthesis that can be conformally attached on the eye-surface. A LCP fabrication process using monolithic integration and conformal deformation was established enabling miniaturization and a batch manufacturing process as well as eliminating the need for feed-through technology.

A polymer-based multichannel cochlear electrode array.

Objective: Compared with conventional cochlear electrode arrays, which are hand assembled and wire-based, polymer-based implants have several advantages. They are very precise, and their fabrication is inexpensive because of the use of thin-film processes. In the present study, a cochlear electrode array based on a high-performance liquid crystal polymer material is devised.

A liquid crystal polymer-based neuromodulation system: an application on animal model of neuropathic pain.

Objective: We developed a custom-made miniaturized neural stimulation system with a liquid crystal polymer (LCP)-based electrode array for animal experiments. In order to verify the feasibility of the system, motor cortex stimulation (MCS) was applied on the rat pain model induced by sciatic nerve injury.

Materials And Methods: LCP is mechanically stable and chemically inert and has a much lower water absorption rate than other biocompatible polymers such as polyimide or parylene.

Modiolus-hugging intracochlear electrode array with shape memory alloy.

In the cochlear implant system, the distance between spiral ganglia and the electrodes within the volume of the scala tympani cavity significantly affects the efficiency of the electrical stimulation in terms of the threshold current level and spatial selectivity. Because the spiral ganglia are situated inside the modiolus, the central axis of the cochlea, it is desirable that the electrode array hugs the modiolus to minimize the distance between the electrodes and the ganglia. In the present study, we propose a shape-memory-alloy-(SMA-) embedded intracochlear electrode which gives a straight electrode a curved modiolus-hugging shape using the restoration force of the SMA as triggered by resistive heating after insertion into the cochlea.

Ventral posterolateral deep brain stimulation treatment for neuropathic pain shortens pain response after cold stimuli.

Neuropathic pain is often severe. Deep brain stimulation (DBS) is a treatment method for neuropathic pain, but its mechanism of action remains unclear. Patients with neuropathic pain are affected by various stimulations, such as mechanical and cold stimuli, but studies of cold allodynia showed the associated pain to be less than that caused by mechanical stimuli.

Magnetic Resonance Imaging Compatibility of the Polymer-based Cochlear Implant.

Objectives: In this study, we compared the magnetic resonance (MR) image artifacts caused by a conventional metal-based cochlear implant and a newly developed liquid crystal polymer (LCP)-based device.

Methods: The metal-based cochlear implant system (Nurobiosys Co.) was attached to side of the head of a subject and the LCP-based device was attached to opposite side.

VPL-DBS on neuropathic pain rat model is effective in mechanical allodynia than cold allodynia.

Recently, deep brain stimulation (DBS) is widely used in various types of neurodegenerative disorders for minimal invasiveness and safety of the procedure. Deep brain stimulation is consistently applied for the treatment of patients with neuropathic pain even though the success rate is not as high as other neurodegenerative disorders. Furthermore, it is also unclear how DBS improves neuropathic pain.