Mechanistic Studies on Video-guided Acupuncture Imagery Treatment of Pain

Verum acupuncture will be applied on the right SP6 and SP9. For each subject, leg position, acupoint location, and needling parameters (1-2 cm depth, 120 rotations / minute, 90˚ insertion angle, moderate deqi sensations on a 0-10 scale) will be kept constant. For the low dose acupuncture group, needles will be rotated at one point and then the other in 15-second rotations with 20-30 second breaks. The specific starting acupoint will be randomized across subjects but kept consistent for each subject across sessions.

Placebo acupuncture will be applied at two sham points using specially designed sham acupuncture needles \[20, 35, 104-106\]. The sham needles differ from regular needles by possessing blunt and retractable tips. Instead of penetrating the skin, the point of the Streitberger needle retracts up the handle shaft when the acupuncturist presses it against the skin. This sham device has been validated by studies showing that subjects cannot distinguish between genuine and sham needling \[20, 35, 104\]. Two sham points will be used during placebo acupuncture: sham point 1 is located 1 cun posterior to the superior 1/3 of K9 and K10. Sham 2 is located 1 cun posterior to K8. Both points are located on the leg where there is no meridian passing through. Sham acupuncture treatment will be the same as verum acupuncture.

In Session 1, all patients will first be introduced to acupuncture treatment, particularly the sensation evoked by acupuncture needles. This will be followed by a five-minute acupuncture exposure applied by a licensed acupuncturist. The exposure will include multiple acupuncture needle manipulations across the two acupoints (SP 6 and SP 9) used in this study. The paradigm applied will be identical to real acupuncture treatment, and the procedure will also be video recorded for the following session. At the beginning of the VGAIT session, patients will be trained for imagery acupuncture outside the fMRI scan. Subjects will first read a script introducing the imagery acupuncture treatment. Then, VGAIT will be applied during scanning. Identical to the acupuncture treatment, there are two fMRI scans during VGAIT, each lasting about 10 minutes. We will ask the patient to measure the sensations they feel during treatment using the MGH Acupuncture Sensation Scale (MASS) after treatment.

The control condition will be the same as VGAIT, except we will use cotton swabs repeatedly touching at non-acupoints with a frequency of about 1 Hz using the same paradigm of verum / sham acupuncture. They will also read a script describing what they are about to see. Then, VGAIT control will be applied during scanning. We will ask the patient to measure the sensations they feel during treatment using the MASS after treatment.