Endogenous event-related potentials in acupuncture clinical research: A critical narrative review.

Acupuncture lacks well-established electrophysiological indicators for objective efficacy evaluation. Endogenous event-related potentials (ERPs), with their millisecond temporal resolution, offer a unique window into the modulatory effects of acupuncture on cognitive and emotional processing. This review summarizes studies conducted over the past decade that have utilized endogenous components such as P300, mismatch negativity, and contingent negative variation to evaluate the efficacy of acupuncture. It covers two major fields, cognitive disorders and neuropsychiatric diseases, and includes studies examining the effects of different acupoints, acupuncture manipulation, and stimulation parameters on ERPs. Most of the reviewed studies reported improvements in event-related potential (ERP) parameters before and after acupuncture-related treatments, and some also observed associations between ERP changes and clinical symptom improvement. However, existing studies share several common methodological shortcomings, including difficulties in attributing effects in combined treatment designs, a general lack of ERP reliability validation, and high methodological heterogeneity. Consequently, current findings should therefore be regarded as exploratory intermediate physiological signals rather than conclusive confirmation of acupuncture efficacy. Future research will require stricter design controls, systematic reliability assessment, and standardized acquisition protocols to progressively evaluate the translational potential of endogenous ERPs in acupuncture research.