Participants will receive electroacupuncture at a frequency of 5 Hz at four acupoints: Liangmen (ST21) and Tianshu (ST25) (local acupoints), and Zusanli (ST36) and Xiajuxu (ST39) (distal acupoints). Disposable needles will be inserted until the "deqi" sensation is achieved. The needles will be connected to an SDZ-IIB electroacupuncture device set at 5 Hz, with stimulation lasting 30 minutes per session. Participants will receive 3 sessions per week for 4 weeks (total: 12 sessions). This group aims to evaluate the efficacy of low-frequency electroacupuncture for treating functional dyspepsia.

Participants will receive electroacupuncture at a frequency of 100 Hz at the same four acupoints: Liangmen (ST21), Tianshu (ST25), Zusanli (ST36), and Xiajuxu (ST39). Needles will be inserted to induce the "deqi" sensation and connected to an SDZ-IIB device set at 100 Hz, with stimulation lasting 30 minutes per session. Participants will receive 3 sessions per week for 4 weeks (total: 12 sessions). This group assesses the efficacy of high-frequency electroacupuncture for functional dyspepsia.

Participants will receive sham electroacupuncture at the same acupoints: Liangmen (ST21), Tianshu (ST25), Zusanli (ST36), and Xiajuxu (ST39). Non-penetrating needles will touch the skin but will not induce "deqi." A sham electroacupuncture device (no actual current) will be used, and treatment will last 30 minutes per session. Participants will receive 3 sessions per week for 4 weeks (total: 12 sessions). This arm serves as a placebo control to evaluate the true effect of electroacupuncture.

Intervention Description:

The intervention in this study involves the use of electroacupuncture (EA), a combination of traditional acupuncture and electrical stimulation.

Acupoints Selection: Electroacupuncture will be performed at specific acupoints associated with the stomach and digestive system. The local acupoints chosen are Liangmen (ST21) and Tianshu (ST25), while the distal acupoints are Zusanli (ST36) and Xiajuxu (ST39). This selection is based on Traditional Chinese Medicine (TCM) principles for treating functional dyspepsia.

Frequency: 5 Hz

The primary outcome is the percentage of participants experiencing symptom improvement using the 7-point Likert scale for Overall Treatment Effect (OTE).

The Overall Treatment Effect (OTE) questionnaire was categorized as "extremely worse than baseline," "worse than baseline," "slightly worse than baseline," "no change," "slightly improved than baseline," "improved than baseline," or "much improved than baseline."

Participants will rate their symptom severity compared to baseline, and those reporting "improved than baseline" or "much improved than baseline"will be considered responders.

The primary outcome will assess the efficacy of 5 Hz and 100 Hz electroacupuncture compared to sham treatment.

The second primary outcome is the rate of complete resolution of the main symptoms of functional dyspepsia at week 4. For Postprandial Distress Syndrome (PDS), the primary symptoms are postprandial fullness and early satiety; for Epigastric Pain Syndrome (EPS), the main symptoms are epigastric pain and burning. Complete resolution is defined as a score of 0 for the respective main symptoms on a validated symptom severity scale.

The severity of each symptom is divided into: no symptoms (0 points), mild (1 point), moderate (2 points), and severe (3 points).

The outcome will compare the resolution rates between the 5 Hz, 100 Hz, and sham electroacupuncture groups.

The Global Overall Symptom (GOS) score assesses eight symptoms associated with functional dyspepsia (e.g., epigastric pain, burning, fullness, early satiety, nausea, bloating). Scores range from 1 (no problem) to 7 (very severe problem).

Scoring is as follows: 1 = no problem (no symptoms); 2 = minimal problem (can be easily ignored); 3 = mild problem (can be ignored with effort); 4 = moderate problem (cannot be ignored, but does not interfere with daily activities); 5 = moderately severe problem (cannot be ignored, occasionally limits daily activities); 6 = severe problem (cannot be ignored, often limits concentration on daily activities); 7 = very severe problem (cannot be ignored, severely limits daily activities.

The change from baseline to week 4 will be compared between the 5 Hz, 100 Hz, and sham electroacupuncture groups.

This outcome will assess whether the efficacy of 5 Hz and 100 Hz electroacupuncture differs between patients with Postprandial Distress Syndrome (PDS) and Epigastric Pain Syndrome (EPS). The primary and secondary outcome measures (symptom improvement, main symptom resolution, and quality of life scores) will be analyzed separately for these two subgroups. The comparison aims to determine if electroacupuncture has varying levels of effectiveness depending on the functional dyspepsia subtype.