Scientists working at TU Berlin, Germany, and Korea University, Korea have designed a new brain-computer control interface to control a lower limb exoskeleton by detecting and decoding signals from within the user's brain. This is not the first brain-computer control interface. Similar research projects were conducted before with promising results.
The system is using an electroencephalogram (EEG) cap to give the possibility that the users of the exoskeleton move forwards, sit and stand, turn left and right by simply staring at one of five flickering light emitting diodes (LEDs). The Journal of Neural Engineering published details about the project.
The five LEDs flicker at a different frequencies and this frequency is reflected within the EEG readout when the user focuses their attention on a specific LED. This identified signal is further used to control the exoskeleton.
A challenge encountered by the researchers has been encountered when trying to separate the signals associated with other brain activity from the precise brain signals used to control the exoskeleton as well as the highly artificial signals generated by the robotic device.
According to Klaus Muller, one of the authors of the paper, lots of electrical noises is created by the exoskeletons. This noise can make harder to detect the EEG signal. However, the scientist explained, their system was able to separate the EEG signal, as well as "the frequency of the flickering LED within this signal".
The paper reports tests on healthy individuals, however, the system is aimed to aid disabled people or sick people. Muller explained that people with high spinal cord injuries or amyotrophic lateral sclerosis (ALS) face difficulties using their limbs or communicating. The system designed by his research team can help them walk and communicated again by decoding what they intend directly from their brain signals.
The brain-computer control interface could serve as a feasible and technically simple add-on to other devices. It is expected that the hardware and the EEG caps will soon emerge on the consumer market.
According to Muller, it only took volunteers a few minutes learn how to operate the system. The researchers are trying now to reduce the 'visual fatigue' associated with LED light flickering and longer-term users of such systems.
Miller concludes that the study shows it is possible to use the brain-computer interface to easily control an exoskeleton system in an intuitive way.
