Paralyzed or paretic muscles can be made to contract by applying electrical currents to the intact peripheral motor nerves innervating them. When electrically elicited muscle contractions are coordinated in a manner that provides function, the technique is termed functional electrical stimulation (FES). In more than 40 years of FES research, principles for safe stimulation of neuromuscular tissue have been established, and methods for modulating the strength of electrically induced muscle contractions have been discovered. FES systems have been developed for restoring function in the upper extremity, lower extremity, bladder and bowel, and respiratory system. Some of these neuroprostheses have become commercialized products, and others are available in clinical research settings. Technological developments are expected to produce new systems that have no external components, are expandable to multiple applications, are upgradable to new advances, and are controlled by a combination of signals, including biopotential signals from nerve, muscle, and the brain.

<Worldwide Neurotechnology Market>

Developed system for preclinical test

Deep Brain Stimulation(DBS), one form of neural prostheses, has been introduced first by Grenoble group in 1980s.¹⁾, During the last decade, DBS of the Subthalamic Nucleus (STN) emerged to the most frequently applied surgical therapy for movement disorders, representing a most promising breakthrough in the treatment of advanced PD. Following pioneering works showing striking improvements in PD patient’s motor function and quality of life, an increasing number of groups started to use DBS worldwide as a routine method for treatment of advanced PD. Medtronic first diveloped commercial DBS implanted system, Activa® Therapy, in 1996 and now more than 30,000 patients worldwide are implanted Medtronic's DBS system.²⁾ However, as the mechanism of the action of DBS has not been elicited perfectly yet and thus the data from High freqeuncy deep brain stimulation(HFS) on 6-hydroxydopamine (6-OHDA) induced animal PD models can contribute to understand the mechanism. In our lab, implantable DBS system for a rat PD model is developed for long term study experiments are in progress.

The number of patients with high cervical spinal cord injury(SCI) is 500,000 world-widely (250,000 in US). Mechanical ventilator has many disadvantages (e.g. physical discomport, difficulty with speech, mortality, impaired sense of smell and so forth) and phrenic nerve pacing carries some risk of injury to the phrenic nerves. So Diaphragmatic Breathing Pacemaker (DBP) can be an appropriate solution where transmission coils are located on the skin of the breast.

<For Cervical Spinal Cord Injury (in Million Dollar Baby, 2004)>

Breathing pacemaker that uses a minimally invasive laparoscopic procedure to position intramuscular electrods bilaterally near the motor point of the diaphragm, can be an alterative to direct stimulation of the phrenic nerve. The connection between ECU (external control unit) and IRU (Internal receiving unit) uses transcutaneous energy transmission (TET). Recently, coil design for more efficient enery trnasmission, detection of self respiration and synchronization of stimulation are in progress.

<Block Diagram of DBP & Developed System>

• 파킨슨병도 '수술로 고친다'
• '국가 뇌과학연구소'설립 본격화(2007/03/12)