Microelectrode Brain-machine Interface

INTRODUCTION Spinal cord injury (SCI) is a debilitating condition that affects over 250,000 people in the United States [1]. It results in paraplegia (paralysis of the lower limbs) or in tetraplegia (paralysis of the body below the neck) depending on where along the spinal column is affected [2]. It can result from either a physical injury to the head or spine or can be caused by a degenerative disease that prevents motor signals from reaching their targets. When an individual suffers from SCI, his or her ability to complete activities of daily living is diminished [2]. The inability to do tasks like reaching for an object or going to the bathroom also affects the individual’s quality of life. A survey was conducted with those affected by SCI to understand the effects of it on daily life [2]. The participants were asked which abilities were most important to regain as well as asked what types of treatments they were willing to undergo to restore function. Many indicated willingness for a surgery after hearing about brain-machine interface (BMI) technology. The technology has been used and tested in monkeys with success [3]. Monkeys were able to incorporate the technology, often a robotic arm, into their thinking and control it to accomplish tasks. After the demonstration of safety and efficacy in monkeys, simple BMI devices were tested in humans for single tasks, but this technology had a large learning curve. The BMI technology about which the survey participants learned would restore ability in many tasks. This works because SCI does not damage the brain [2]. The neurons and connections are left intact. Prior work has been done mapping the motor cortex with electroencephalography [3]. This allows current researchers to know where to place the electrodes in the brain for the BMI to control a robotic arm. However, the signals from the brain still need to be interpreted to be useful for controlling these neural robotics. The Michelangelo Hand is an example of brand new advancements in the precision, control, and functional abilities in these neural robotics [4]. The goal of these products is to aid those in need of a functioning hand. While basic control of these robotics can be demonstrated [3], precision is important for some activities of daily living. This research draws correlations between neural signals and the movement of a robotic arm to better understand this connection and improve the capacity of control for a robotic arm.