Based on the evidences from the studies in both animals and humans, EA has the potential for treating gastrointestinal motility disorders. As shown in the summary table, EA increases LES pressure and reduces TLESRs, and therefore may be beneficial to patients with GERD. With regarding to gastric motility functions, it seems that EA enhances gastric accommodation, slow waves, contractions and emptying; suggesting a therapeutic potential for functional dyspepsia and gastroparesis. Little is reported on the effect of EA on small intestinal motility and therefore its role for treating patients with intestinal motility disorders has not been established. Similarly, not much is known on the effect of EA on colon motility and the therapeutic effects of EA for common functional bowel disorders, such as IBS, constipation and diarrhea, are not conclusive.
Acupuncture or EA has advantages of being noninvasive and practiced for many years. Accordingly, ample clinical data are available on the application of EA for treating various disorders. With regard to its applications for the treatment of gastrointestinal motility diseases, however, there are a number of problems: 1) most of the available methods used for the assessment of gastrointestinal motility are noninvasive, making it less feasible for basic and clinical research; 2) patients with functional gastrointestinal disorders are heterogeneous with unclear pathophysiologies or pathogenesis, and therefore the outcome of the treatment of these patients is typically controversial not only with EA but also with other therapies; 3) based on our review of the literature, there are also issues including the methodology of EA, study design and outcome measurements. Different methods have been used for the implementation of acupuncture, including, manual acupuncture, EA, TEA and acupressure, and these different methodologies make it difficult for the comparison of the efficacy of EA. In some studies, the parameters of EA that are important for the success of the therapy (Han, 2003
) were not mentioned or appropriately determined; whereas in other studies, the experimental designs were not adequate and the measurement methods were inadequate.
We believe that EA has a great therapeutic potential for treating gastrointestinal motility disorders and functional gastrointestinal diseases. Future clinical studies with EA should follow rigid scientific designs, optimize methodologies and apply cut-edge outcome measures. In most of clinical studies, symptoms (subjective) are primary endpoints and therefore the experiment must be controlled and blinded if feasible. For the implementation of EA, efforts should be made in the selection of acupoints and stimulation parameters, the duration and frequency of EA. In addition, physiological measurements should also be made in clinical studies to understand possible mechanisms and pathways involved with EA.
In conclusion, acupuncture or EA is able to alter gastrointestinal motility functions and improve gastrointestinal motility disorders. However, more studies are needed to establish the therapeutic roles of EA in treating functional gastrointestinal diseases, such as GERD, functional dyspepsia, IBS, constipation and diarrhea.