Significance of "Deqi" Response in Acupuncture Treatment: Myth or Reality

This review article examines the Deqi phenomenon in acupuncture, a sensation described in traditional Chinese medicine as the excitation of qi (vital energy) in the meridians through needle stimulus. Deqi has been regarded as an important parameter for achieving therapeutic efficacy in acupuncture for more than 2,000 years, as described in the Yellow Emperor's Classic of Internal Medicine. The authors, Zhou and Benharash from the University of California, Los Angeles, sought to analyze this traditional concept from a modern neurophysiological perspective. The sensations associated with Deqi include numbness, dull aching, distention, heaviness, tingling, and sometimes sharp pain.

Functional magnetic resonance imaging studies by Hui and colleagues have characterized these sensations, showing that dull ache, pressure, and heaviness are the most common, followed by tingling, numbness, and warmth. Interestingly, when local anesthetics are applied before acupuncture, both Deqi and analgesia disappear, suggesting a direct connection. Neurologically, Deqi involves multiple types of nerve fibers, from fast-conducting myelinated A-beta fibers to slow-conducting unmyelinated C fibers. Experiments have identified that the slower-conducting A-delta and C fibers are involved in the dull-ache component of Deqi, whereas numbness and tingling may involve A-beta fibers.

Needling depth is crucial — studies confirm that penetration of the muscle layer coincides with the Deqi sensation, and stimulation of deep, but not cutaneous, tissues is associated with the analgesic response. An important difference between Deqi and common pain is the sequence of sensations: in typical pain, a sharp sensation is followed by a dull ache, but in Deqi, the dull component precedes any sharp sensation. Functional MRI studies show that Deqi can deactivate the limbic system, whereas painful stimuli activate it, partly explaining why Deqi is not perceived as unpleasant. The correlation between Deqi and therapeutic efficacy has been documented in several studies.

Research conducted in China between 1950 and 1980 on acupuncture anesthesia corroborated the importance of Deqi. More recent studies, such as that by Takeda and Wessel, found that Deqi can predict significant improvement in osteoarthritis pain, although some studies have reached conflicting conclusions. The frequency of Deqi observed across studies is approximately 70% when all acupuncture points are combined, which interestingly coincides with the 7:3 responder-versus-non-responder ratio observed in clinical practice. When true acupuncture was compared with tactile stimulation, Deqi was reported in 98% of subjects receiving acupuncture versus only 27% of those receiving tactile stimulation.

To quantify Deqi scientifically, several questionnaires have been developed, including the Acupuncture Sensation Scale and the Southampton Needle Sensation Questionnaire. These instruments generally categorize sensations into two groups: true Deqi (including dull ache, heaviness, numbness, radiation) and sharp pain at the site (including burning, stabbing, and shock-like sensations). The clinical implications of this research are significant for acupuncture practice. Understanding Deqi from a neurophysiological perspective allows practitioners to perform quantitative assessments and obtain more reliable treatment prognoses.

However, the authors acknowledge important limitations: the need for more basic research to mechanistically relate Deqi to analgesia, the lack of uniformity in assessment methods, and the need for large-scale studies with scientific validity to convincingly demonstrate the necessity of achieving Deqi for therapeutic efficacy.