Effects of Laser Acupuncture on Pain Sensitivity, Cognitive Performance, and Brain Activity in Healthy Adults

Laser acupuncture is a non-invasive therapeutic technique that applies low-level laser therapy (LLLT) to acupuncture points to stimulate physiological responses. This technique uses a laser applicator that emits low-level laser light when applied directly to the skin surface of specific acupuncture points. The participant will remain seated comfortably during the treatment. A low-level laser device will be used to irradiate pain-related acupuncture points including Hegu (LI4), Quchi (LI11), and Zusanli (ST36). The order of acupoint stimulation will be randomized for each participant and for each session. The selected acupoints (LI4, LI11, and ST36) were chosen based on the acupoint analysis conducted in our previous Systematic review. These three acupoints were consistently identified across studies addressing pain management, pain-threshold modulation, autonomic regulation, and cortical activity in healthy participants. Therefore, these acupoints may be regarded as pain-related acupoints for investigating both behavioural and neurophysiological effects of laser acupuncture. Each acupoint will receive 5 minutes of continuous laser stimulation per session. Laser device: LightNeedle 300, Laser class 3B. The parameters of the laser device are as follows: Wavelength: 655 nm Power output: 50 mW Probe cable: 0.7 m Beam divergence: 0,157 rad Energy density: 7.5 J/cm² per point Mode: Continuous wave Each participant will receive four laser acupuncture sessions in total. Each complete session will last approximately 120 minutes, including pre- and post-treatment assessments. The intervention will be delivered face-to-face in a controlled university research laboratory by a trained acupuncturist experienced in both traditional acupuncture and laser therapy. Standardized treatment protocols will be strictly followed to ensure consistency across sessions. Session fidelity will be assessed through direct observation, and adherence will be monitored by trained research personnel. A 48-hour washout period will be implemented between different treatment conditions in accordance with the crossover trial design.