The goal of this clinical trial is to learn about using the latest transcranial alternating current stimulation (tACS) to reduce the incidence of delirium in patients with subarachnoid hemorrhage. The main question it aims to answer is:

• To evaluate the effect of tACS on reducing delirium in patients with subarachnoid hemorrhage.

Participants will treated with real tACS or sham tACS. Researchers will mainly compare the two groups to see if patients' delirium will reduce by using tACS.

Research objectives: To reduce the incidence of delirium in patients with subarachnoid hemorrhage by using the latest transcranial alternating current stimulation.

Research contents:

1. To evaluate the effect of transcranial alternating current stimulation on improving sleep quality in patients with subarachnoid hemorrhage;
2. To evaluate the effect of transcranial alternating current stimulation on reducing delirium in patients with subarachnoid hemorrhage.

Research hypothesis: Transcranial alternating current stimulation can improve sleep quality and reduce the incidence of delirium in patients with subarachnoid hemorrhage.

Study design:

1. double-blind randomized clinical trial
2. Subjects：Patients with subarachnoid hemorrhage admitted to the neurosurgical intensive care unit during the study period.
3. Number of participating centers and names of centers: Single research center, Xuanwu Hospital, Beijing
4. Sample size: The total number of plans was 74, and the total number of study centers was 74.
5. Grouping of subjects：The random number table method was used for randomization, and the envelope method was used for randomization. The random serial number was stored in an airtight envelope, a patient was admitted, and an envelope was opened.
6. Intervention measures: ① The control group was treated with sham transcranial electrical stimulation; ② The experimental group was treated with real transcranial electrical stimulation.
7. Outcome measures: ① Efficacy indicators: the incidence and duration of delirium; The scores of Richard Campell sleep questionnaire, Hamilton Anxiety Scale, Mini-Mental State Examination, numerical rating scale for pain and muscle strength were recorded.② Safety indicators: the incidence of adverse reactions.

Inclusion Criteria:

• Subarachnoid hemorrhage was consistent with the Chinese Guidelines for the Diagnosis and Treatment of Subarachnoid Hemorrhage 2015;
• Patients after completion of surgical treatment;
• over 18 years of age;
• Hunt & Hess grade I-III;
• No major organ failure;
• The patient has no speech or hearing impairment;
• Informed consent of patients and their families, signed informed consent.

Exclusion Criteria:

• Those who have delirium at the time of enrollment;
• had substance abuse/dependence within 6 months before enrollment;
• had suffered from other mental illness within 6 months before enrollment;
• Suffering from serious or unstable organic diseases;
• Pregnant or lactating women and those planning to become pregnant in the near future;
• Damaged skin integrity at the electrode placement site, allergic to electrode gels or adhesives.
• with an implanted electronic stimulator;
• Patients who had received other noninvasive neuromodulation therapy within 1 month before enrollment;
• Participants in any other clinical trial within 1 month prior to baseline;
• There are circumstances in which the researcher considers it inappropriate to participate in this study.

The random number table method was used for randomization, and the envelope method was used for randomization. The random serial number was stored in an airtight envelope, an envelope was opened when a patient was admitted.