Brain computer interface (BCI) has always been a key research field in the global science and technology field. At present, the research on non-invasive brain computer interface has gradually become the main direction of various technology giants and start-ups, and the non-invasive brain computer interface equipment has been exhibited at CES 2020.
A non-invasive brain computer interface device
Recently, Mr. Zhang, a high paraplegic patient, picked up coke with “one hand” with the help of “idea”, and successfully drank it into his mouth. The above results were published by the “brain computer interface” team of Zhejiang University Qiushi Institute of advanced research, which is the first clinical transformation research of implantable brain computer interface in China.
It is understood that the project is called “clinical transformation and Application Research of implantable brain computer interface”, which was completed by the team of Professor Zhang Jianmin of the Second Affiliated College of Zhejiang University and the team of Professor Zheng Xiaoxiang and Professor Wang Yueming of Qiushi Institute of higher research of Zhejiang University.
1. Robot assisted microelectrode implantation
After obtaining the informed consent and signature of Mr. Zhang and his family members, Professor Zhang Jianmin’s team implanted Utah array electrodes into the fifth layer (6 layers in total) of Mr. Zhang’s motor cortex, which controls the movement of his right upper limb. The array electrode is only 4mm * 4mm in size, and there are 100 electrode pins on it. Each pin can detect the discharge of one or more neurons. In order to avoid errors, the team also used a surgical robot with a step of 0.1 mm during the operation, which also made the operation the first successful electrode implantation operation assisted by surgical robot in the world.
The other end of the electrode is connected with a computer. The latter has built-in robust online decoder and feedback learning system, which can record the neural signals of the brain in real time and convert them into the action instructions of the manipulator, and finally form a “bidirectional mutual adaptive closed-loop BCI system”.
Schematic diagram of microelectrode implantation
2. Acquisition and analysis of brain nerve signal
At present, the reported cases of implantable brain computer interface in the world are young and middle-aged people, and the patients in this project are elderly people, and the stability of brain nerve signal is also weakened. The team introduced nonlinear and neural network algorithms, and designed a set of programs specifically for elderly patients, and ultimately achieved better results of brain nerve signal acquisition and analysis.
Flow chart of brain nerve signal acquisition and feedback
3. Running in training of patients and manipulators
The team first trained through the mouse control training on the computer screen and the robot arm moving in the specified direction, and then simulated the actions of drinking water and eating. After 4 months, the current achievements have been achieved in a step-by-step manner.
4. Brain computer interface will become the gospel of the majority of paralytic patients
The successful clinical application of brain computer interface technology proves that brain computer interface technology in China has the ability of practical application, and patients can complete more actions with the help of this technology, which can greatly improve the quality of life of patients.
It is understood that there are nearly 100 million patients with sequelae of limb paralysis caused by stroke, brain and spinal cord injury in the world, and there are 23 million in China alone. Although BCI implantation is not permanent at the time of invasion, BCI has greatly changed the life of the majority of patients with paralysis, and let them see the hope of improving the quality of life.
5. Brain computer interface application scenarios
As a technology closely related to organisms, the maturity of brain computer interface technology also needs clinical research. Since 2005, more and more enterprises and institutions have carried out clinical research through invasive or non-invasive methods, and made breakthrough progress.
Compared with foreign countries, the domestic research on BCI is still in the early stage, and the direction is more non-invasive. Based on the non-invasive way, people only need to use the head wearable device with electrodes to obtain the signal. Compared with the invasive type, the non-invasive type may be inferior to the former in terms of interference and accuracy of information acquisition, but it also avoids the rejection reaction of human body and the risk of surgery.
In terms of landing, BCI is the most valuable scene in the medical field. Several cases have proved that BCI technology can help the disabled and the elderly carry out corresponding rehabilitation training, or regain the ability of limb control and perception. In addition, in the fields of education, entertainment, military and sports, the potential market of BCI is also great. Some domestic enterprises have launched non-invasive brain computer interface equipment for commercial use, but in some non-medical markets, the product landing has been questioned by the society on data security, ethics and other aspects.
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