Speaker - Dr. Zhao

Jingpu Zhao
Deputy Chief Physician, Department of Rehabilitation Medicine, The First Affiliated Hospital of Shenzhen University

Live Broadcast Excerpts

Good evening, all friends of Brain Hacker. I am very glad to use this evening to share with you the research and application of rTMS and tDCS in promoting awakening. I am Dr. Zhao Jingpu from the Rehabilitation Center of Shenzhen Second People's Hospital, the First Affiliated Hospital of Shenzhen University.

Disturbance of consciousness is a relatively new topic in the field of rehabilitation in recent years, because with the development of intensive care medicine and the improvement of rescue technology, more and more patients are rescued in the early stage of the disease, and a large part of them may fall into disturbance of consciousness afterwards.

01 Classification of disturbance of consciousness

Disturbance of consciousness is a very extreme functional impairment. It includes two parts, the first is called arousal; the second is called awareness. For a normal person, his arousal and awareness are at the highest level; but for a coma patient with impaired consciousness, his arousal is at the lowest level, and his awareness is also at the lowest level. But what needs to be emphasized here is that arousal is used to evaluate whether the patient is awake, and awareness is a perception of the outside world on the basis of his awakening.

Between normal and comatose patients is the vegetative state, his wakefulness is at a relatively high level, patients are often awake, but unfortunately this kind of patients have no perception of the outside world, that is, we say wakeful coma, many TV dramas appear in such a vegetative state of patients. In addition, there is another disturbance of consciousness called the minimally conscious state MCS. This type of patient is at the highest level of awakening. This patient is also awake. Compared with the vegetative state, he mainly has his perception of the outside world. His perception will fluctuate within a certain range. The arrow in the picture shows that his perception fluctuates from the smallest to the highest.

02 The mechanism of TDCS to promote awaking

Regarding the mechanism of transcranial direct current stimulation to promote awakening, we first look at the above two figures, the first one on the left is to show that transcranial direct current stimulation can affect the current change of brain neurons, but this change only plays a regulatory role, can not produce action potential, can only be stimulated under the threshold. Another mechanism is that transcranial direct current stimulation can reach the cerebral cortex, and we see this picture on the right, with traditional TDCS on the top and HD-TDCS on the bottom. Both use electrodes to stimulate the yellow-green area. The traditional stimulation range is relatively wide, and compared with HD-tDCS stimulation, it is not so accurate.

Let's look at the following two pictures. The left side shows an experiment, using hd-tdcs, 1mA, to stimulate for 20 minutes, and then observe the continuous effect of this stimulation. By assessing the mep of the cerebral cortex at regular intervals, it was found that this mep change can last for about an hour and 60 minutes at the longest. The last picture shows that transcranial direct current stimulation can cause changes in the hemodynamics of the cerebral cortex.

Note: The above content is part of the text without changing the original meaning from the speakers. To watch the full live video (in Chinese), please go to Live Broadcast Entrance.