Modern acupuncture-like stimulation methods: a literature review

Acupuncture therapy has been proved to be effective for diverse diseases, symptoms, and conditions in numerous clinical trials. The growing popularity of acupuncture therapy has triggered the development of modern acupuncture-like stimulation devices (ASDs), which are equivalent or superior to manual acupuncture with respect to safety, decreased risk of infection, and facilitation of clinical trials. Here, we aim to summarize the research on modern ASDs, with a focus on featured devices undergoing active research and their effectiveness and target symptoms, along with annual publication rates. We searched the popular electronic databases Medline, PubMed, the Cochrane Library, and Web of Science, and analyzed English-language studies on humans. Thereby, a total of 728 studies were identified, of which 195 studies met our inclusion criteria. Electrical stimulators were found to be the earliest and most widely studied devices (133 articles), followed by laser (44 articles), magnetic (16 articles), and ultrasound (2 articles) stimulators. A total of 114 studies used randomized controlled trials, and 109 studies reported therapeutic benefits. The majority of the studies (32%) focused on analgesia and pain-relief effects, followed by effects on brain activity (16%). All types of the reviewed ASDs were associated with increasing annual publication trends; specifically, the annual growth in publications regarding noninvasive stimulation methods was more rapid than that regarding invasive methods. Based on this observation, we anticipate that the noninvasive or minimally invasive ASDs will become more popular in acupuncture therapy.