D2.1 Requirements and Specification - CORBYS

D2.1 Requirements and Specification
15 State­of­the­Art in Non­Invasive Brain Computer Interface (BBT)
The objective of CORBYS project is to develop the underlying design principles of a cognitive robotic system
with the focus on augmenting human locomotion capabilities. One of the key points of these principles is the
way that the human and the robot interact and share their cognitive capabilities. In this area, the large
majority of research was concentrated in a uni-directional way, where the human delivers orders to the
machine responsible for the execution of the commands. The focus has been on exploring and improving the
way that robots understand natural human expressions (e.g. understanding natural language, gestures, etc).
However, very little research has concentrated on a mutual exchange of cognitive information. This is
because this information mainly resides in the human brain and progress was still required in brain computer
interfacing. A few years ago there was much research in understanding how to decode this information from
brain imaging techniques, leading to one of the objectives of CORBYS: to use brain computer interface
technology to online decode human cognitive information. This information will be used to build a natural
way of communication between the human and the robot, and to guide the design and operation principles of
the cognitive robot.
In this context the Brain-computer interfaces (BCI) emerge as systems that make it possible to translate the
electrical activity of the brain in real-time using commands to control devices. They do not rely on muscular
activity and can therefore provide communication and control for people with devastating neuromuscular
disorders such as the amyotrophic lateral sclerosis, brainstem stroke, cerebral palsy and spinal cord injury. It
has been shown that these patients are able to achieve EEG controlled cursor, limb movement, and prosthesis
control and have even successfully communicated by means of a BCI (Birbaumer et al, 1999; Hochberg et al,
2006; Buch et al, 2008).
The remainder of this Deliverable reviews current non-invasive BCI technology applied to the control of
robots focussing on the CORBYS technology gaps and innovations. Subsequently, the main components of a
BCI system, Hardware, Software, Basic Signal Processing and Decoding will be described in the following
sections, showing the state of the art, the constraints and the respective technology innovations.
15.1 Invasive vs. Non­Invasive BCI Technology and Robotics
Recently there has been a great surge in research and development of brain-controlled devices for
rehabilitation. The most significant characteristic of these systems is the use of invasive or non-invasive
methods to record brain activity. Invasive techniques require a clinic intervention to implant the electrodes on
the cortex, while non-invasive methods place the sensors outside the skull (e.g., Electroencephalogram EEG).
The research arena is dominated by the US for invasive techniques and research in animals, while the EU
leads in the development of non-invasive techniques with direct application on humans. On the one hand, US
teams have achieved significant results using invasive recording methods to control artificial devices. A rat,
for example, was able to move a robotic arm in one dimension to get water (Chapin et al, 1994), monkeys
were trained to move a cursor on a screen and adjust its size (Carmena et al, 2003) and to self-feed using a
robotic arm with a gripper, to grab food in three dimensions (Velliste et al, 2008), and a patient had sensors
implanted directly in the cortex and learned to open and close a prosthetic hand and control a simple robotic
arm in two dimensions (Hochberg et al, 2006). These achievements show that direct and online control of a
robotic device is possible with invasive brain recordings. However, these settings involve technical and
clinical difficulties for humans, such as the maintenance of the electrodes in the cortex, infection risks, and
damage to the brain (Mc Farland & J.R.Wolpaw, 2008).
On the other hand, in line with CORBYS, much research in BCI has focused on non-invasive recording
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