Investigating the efficacy and safety of temporal interference stimulation for patients with disorders of consciousness.

Based on the central loop hypothesis, deep brain stimulation (DBS) represents a commonly utilized neuro-modulation stimulation technology for disorders of consciousness (DOC). It was initially employed in Europe in 1968 for treating DOC. Some patients can regain functional communication capabilities and even resume family life. Nevertheless, as a neurosurgical intervention, DBS implantation entails significant surgical risks and potential complications (such as cerebral edema in the surgical area, secondary cerebral hemorrhage, secondary epilepsy, postoperative brain abscess, pulse generator shutdown or circuit malfunction, displacement of stimulation electrodes or extension leads, rejection reactions), and incurs substantial costs, imposing a heavy burden on patients' families and the national medical insurance fund. Traditional non-invasive brain stimulation methods, such as transcranial alternating or direct current stimulation, although not requiring surgery, have limited focusing capacity and the ability to stimulate deep brain structures. Hence, researchers have been in pursuit of approaches to precisely and effectively stimulate deep brain regions without the need for surgery.

In 2017, the concept of temporal interference (TI) stimulation, a novel non-invasive method for regulating deep brain regions was put forward . The fundamental principle of TI stimulation is that two interfering high-frequency signals will generate a low-frequency amplitude-modulated electric field, which can drive the discharge of deep brain neurons. Furthermore, by fixing the sum of the input currents of two pairs of electrodes and altering the current input ratio of the two pairs of electrodes, the movement of the mouse's forepaws, whiskers, and ears without modifying the spatial position of the electrodes could be achieved. Therefore, TI stimulation enables the flexible movement of the stimulation target area within the brain without electrode displacement. Despite the fact that research on TI technology is still in its nascent stage, this method has demonstrated substantial potential in neuroscience and clinical therapy.

Consequently, the objective of this multicenter randomized controlled trial is to assess the therapeutic effect of temporal interference stimulation in awakening patients with severe disorders of consciousness and verify its safety. Simultaneously, it aims to clarify issues such as the clinical application indications, operational parameters of TI. This will facilitate a deeper comprehension of the effectiveness, clinical application indications, operational parameters, and treatment plans of this emerging neuro-modulation technology as a means of awakening treatment, and promote the advancement of diagnosis and treatment technologies for patients with severe disorders of consciousness.

Inclusion Criteria:

• Severe consciousness disorder patients aged 18 to 75 years old, regardless of gender;
• Patients with severe consciousness disorders, namely a minimally conscious state or vegetative state that lasts for 28 days or more;
• Patients with normal body temperature, stable vital signs, spontaneous breathing, tracheotomy without the use of a metal cannula and with a small amount of sputum, and who are eligible for magnetic resonance imaging (MRI) examination;
• Written informed consent obtained from the patient's family members in advance.

Exclusion Criteria:

• Individuals with a previous history of significant neuropsychiatric and other major disorders such as those involving the heart, lung, liver, and kidney;
• Those who have undergone V-P shunt or Ommaya reservoir implantation and other procedures that may influence the analysis of magnetic resonance scanning signals;
• Patients who are scheduled for V-P shunt or Ommaya reservoir implantation in the near future;
• Pregnant women;
• Those who have participated in other drug or device clinical trials;
• Patients with poorly controlled epilepsy in the recent period;
• Those with infections at the TI stimulation site or compromised skin integrity at the electrode placement site;
• Those currently taking medications prone to inducing epilepsy, such as quinolone drugs;
• Those with intracranial infections, intracranial tumors, or metallic objects within the cranium;
• Those allergic to electrode gel or adhesives;
• Those with implanted electronic devices within the body;
• Those with severe cardiac disorders and those equipped with cardiac pacemakers.

This study is being conducted as a double-blind trial, wherein the surgeons, assessors and participants' family members are kept unaware of the assigned research groups. However, it is necessary to inform the physicians responsible for adjustment of stimulation parameters about the allocation of participants. Follow-up assessments of participants after stimulation will be conducted by an independent assessor using standardized evaluation criteria.