In addition to routine chemotherapy care, the intervention involves the use of a smart breast cancer chemotherapy mindfulness-based integrated virtual reality and multimodal physiological feedback training system module. This will be administered during each of the first to fifth inpatient chemotherapy sessions. The equipment operator, a researcher, will use the AI-Pico Neo 3 Pro headset, featuring a dual-eye resolution of 2880*1600 pixels, a refresh rate of 90Hz, and a 110-degree field of view. The interpupillary distance, headset strap tightness, and volume will be adjusted according to the participant's comfort. The scenario content includes three shared scenes: beach, forest, and starry sky, from which participants can choose based on their preference. Each session will last 12 minutes and be conducted once. Participants will assume a semi-reclining position during the session. Monitoring will be conducted with the researcher assisting the participant on-site.

In addition to routine chemotherapy care, the intervention includes mindfulness-based audio exercises. Participants will use over-ear headphones that play the same content as experimental group A, but without virtual reality. This will be administered during each of the first to fifth inpatient chemotherapy sessions. The equipment operator, a researcher, will use Sony over-ear headphones, adjusting the fit and volume according to the participant's comfort. The audio content includes three background sounds: beach, forest, and starry sky, from which participants can choose based on their preference. Each session will last 12 minutes and be conducted once. Participants will assume a semi-reclining position during the session. Monitoring will be conducted with the researcher assisting the participant on-site.

mindfulness based virtual reality

The Revised Newly Diagnosed Breast Cancer Stress Scale (NDBCSS-R) will be used: This scale consists of 17 items, divided into four parts: Negative Perception (3 items), Threat (4 items), Unpredictability (5 items), and Facing Challenge (4 items). Scoring is based on a 4-point Likert scale, with 3 indicating strong agreement and 0 indicating disagreement. Higher scores indicate a greater level of perceived stress. Items 1, 3, 5, 11, 13, and 15 are reverse-scored.

The Memorial Symptom Assessment Scale (MSAS) will be used: It consists of 32 items. First, participants indicate the presence or absence of symptoms. If symptoms are present, the frequency, severity, and distress of 24 symptoms, and the severity and distress of 8 symptoms, are evaluated. Frequency and severity are assessed using a 4-point scale, with 1 indicating rarely or mild and 4 indicating almost constantly or very severe. If there are no symptoms, the item is scored as 0. Distress is assessed using a 5-point scale, with 0 indicating not at all and 4 indicating very much.

The Cognitive and Affective Mindfulness Scale-Revised (CAMS-R) will be used: It consists of 10 items, rated on a 4-point scale, with 1 indicating almost never and 4 indicating almost always. Higher scores indicate a higher level of mindfulness.

The three-lead electrocardiography (ECG) from the Thought Technology five-channel biofeedback system kit will be used as the measurement tool. Using the NeuroKit2 package in Python, we aim to extract R-peaks from time-series data. Initially, we apply a 60 Hz notch filter to remove powerline noise, followed by a bandpass filter with a frequency range of 0.05 to 100 Hz. To enhance the QRS complex and make the R-peaks more prominent within the signal, we use a dynamic threshold setting based on the signal amplitude from the preceding 15 seconds. Subsequently, we detect the peaks, verify, and correct them. Finally, we calculate the HRV features.