Motor Substitution

BCI Interface and Orthosis

One of the goals of this workpackage is the direct improvement of motor functions or providing alternative methods for their substitution in severely physical disabled persons. Today, the only possibility of restoring grasp function to a certain extends in case of missing surgical options is the application of Functional Electrical Stimulation (FES). However, current FES methods are only applicable if shoulder and elbow functions are preserved to a large extent. Therefore this WP focuses on the development of a brain-controlled FES orthosis to extend the potential user population to patients with restrictions in shoulder, elbow, hand and finger function. This hybrid orthosis will allow direct brain control of a joint angle or for switching the output channel of another assistive device (AD). The TOBI project is currently working on several application to fulfill this objective. In the 6 short videos below, we show several applications of ongoing experiments at TOBI partners:

Hybrid-Brain Computer Interface (h-BCI)

This video demonstrates the basic concept of the use of a hybrid-Brain Computer Interface (h-BCI), i.e. a combination of a brain switch and a shoulder position sensor, for control of an arm neuroprosthesis based on Functional Electrical Stimulation (FES) and a mechanical orthosis.

The subject uses imagination of foot movements to initiate the brain switch and generates an additional analog control signal by moving his shoulder. These signals are used to control stimulation impulses of surface electrodes mounted on the arm of subject together with an upper and lower arm orthosis. The subject, with the help of the BCI and orthosis, grasps the pencil, lifts it to a higher surface and signs a document. When the task is finished he deactivates the BCI with the shoulder sensor.

The subject can switch through predefined control modes (incl. a pause mode) and controls the degree of elbow flexion / extension or the degree of hand opening /closing by movements of his shoulder.

 

 

EPFL videos

Telepresence Robot

This video was shot during a live demo at the European Future Technologies Conference and Exhibition 2011, Budapest, Hungary (http://www.fet11.eu/)
The goal of the telepresence robot is to enable people to interact remotely with their friends and family, therefore it equipped with a screen, microphone and a webcam so that video-chat software such as Skype can be used. It also has a number of proximity sensors and a computer vision algorithm that enable it to detect potential obstacles.
In this video, you can see the telepresence robot being driven in an unconstrained, dynamic environment with a remote BCI. The video stream from the onboard webcam is displayed to the user to facilitate navigation, whilst the output of the BCI feedback is represented by a horizontal bar on the screen. The user performs left and right hand motor imagery to issue high-level "turn left" and "turn right" commands respectively. The shared controller on the robot interprets these commands, given the environmental context, and when no commands are sent by the user, the robot moves forwards whilst automatically avoiding obstacles where necessary.

 

 

EPFL videos

Controlling an Artificial Arm with BCI

This video in German gives a plain explanation on how to control an artificial arm with the help of a BCI system.

TUG videos

FES Hand Orthosis for Long-term Use

This video demonstrates how the BCI can help a person without motor control of his/her hand grasping an object. In this experiment, the user wants to grasp a bottle. Using his own residual motor capabilities, he positions his hand close to the bottle. Then with the help of the BCI he stimulated his paralyzed muscles to grasp the object. The hand orthosis facilitates grasping and is conceived for long-term use as the electrical stimulation can be switched off after the task is executed to avoid muscular fatigue of the user.

In summary:
- the functional electrical stimulation (FES) allows the activation of paralyzed muscles, which are still innervated.
- the orthosis synchronizes the finger movements, and provide a more natural force distribution.
- finally it reduces fatigue since the electrical stimulation can be switched off after locking/grasping.

 

 

EPFL videos

h-BCI Controlled Arm FES-Orthosis

This video demonstrates the basic concept of the use of a hybrid-Brain Computer Interface (h-BCI), i.e. a combination of a brain switch and a shoulder position sensor, for control of a arm neuroprosthesis based on Functional Electrical Stimulation (FES) and a mechanical orthosis.

The subject uses imagination of foot movements to initiate the brain switch and generates an additional analog control signal by moving his shoulder. These signals are used to control stimulation impulses of surface electrodes mounted on the arm of subject together with an upper and lower arm orthosis.
The subject, with the help of the BCI and orthosis, grasps the cup. When the task is finished he deactivates the BCI with the shoulder sensor.

The subject can switch through predefined control modes (incl. a pause mode) and controls the degree of elbow flexion / extension or the degree of hand opening /closing by movements of his shoulder.


UH videos

Multitasking: Writing with a BCI-FES Orthosis

In this demos the user writes, grasping and holding his pen with the help of a BCI controlled hand FES-orthosis.

This experiment shows:

- the use of Non-Invasive Neuroprosthetics controlled by a BCI and activating the subject muscles.
- Asynchronous operation
- Natural interaction paradigm: same hand used for BCI imagination and FES stimulation and writing
- Multitasking and daily living


EPFL videos