Could acupuncture needle sensation be a predictor of analgesic response?

During acupuncture some patients experience distinct sensations which are often referred to as needle sensation. Needle sensation may be related to treatment outcome, although what constitutes adequate acupuncture needle sensation is not known. In this paper, we debate the possibility of using the self-report of the overall intensity of needle sensation as a predictor of analgesic outcome to acupuncture. We describe how our approach to establish criteria to determine adequacy of transcutaneous electrical nerve stimulation interventions in clinical trials has been used to inform our search for markers of adequacy of procedural technique for acupuncture. We describe previous research which has focused on developing tools to capture the nature of the descriptors used by patients when they self-report needle sensation and reveal that little attention has been given to its role in outcome. We demonstrate that needle sensation is a complex phenomenon with subjects using multiple descriptors to report their experience. We argue that the intensity of the overall experience of needle sensation may prove useful as a gross marker of the adequacy of acupuncture. We briefly describe our research which isolates individual components of needling technique, such as depth of needle penetration and bidirectional needle rotation, in order to assess their contribution to overall needle sensation intensity.