After admission to AICU, the experimental group was stimulated at 40Hz for 6h;

After admission to AICU, the control group was not stimulated at 40Hz ;

Exogenous 40HZ stimulation is a physical intervention that can drive oscillations in the gamma range, and the oscillations and pulses caused at the corresponding frequency can lead to a significant reduction in β-amyloid, reverse tau hyperphosphorylation, and thereby improve the cognitive function of patients.

Postoperative delirium was assessed using the CAM-ICU scale.The RASS score (The Richmond Agitation-Sedation Scale) was used to assess arousal. When the patient's RASS score is not -4 /-5, delirium evaluation can continue considering the patient's wakefulness status.CAM-ICU scale contains four features (Feature 1, Feature 2, Feature 3, and Feature 4). Delirium can be diagnosed when the patient is positive for features 1, 2, 3, or 4.

Serum Tau proteomic analysis and CRP, IL-6, and TNF-ɑ were recorded

The Chinese version of the Richards-Campbell Sleep Quality Scale Score (RCSQ) was used to evaluate sleep quality. RCSQ scoring average for five projects, including 0 ~ 25 points on behalf of the poor quality of sleep, on behalf of the sleep quality of 76 ~ 100 points; The higher the score says sleep quality, the better