Applying the Power of the Mind in Acupuncture Treatment of Pain

How does pretreatment expectancy influence pain outcomes with electroacupuncture and battlefield acupuncture in cancer survivors?: Pretreatment expectancy and pain reduction by acupuncture

Background

Outcome expectancy is an important component of non-specific effect that may play an important role in pain research and clinical care. We sought to evaluate whether pretreatment expectancy predicts pain reduction in cancer survivors receiving electroacupuncture (EA) or battlefield acupuncture (BFA).

Methods

We analyzed data from a randomized clinical trial that compared EA and BFA versus wait list control (WLC) for chronic musculoskeletal pain in cancer survivors. Expectancy was measured by the Acupuncture Expectancy Scale (AES) at baseline. Pain severity was assessed using the Brief Pain Inventory (BPI) at baseline and week 12. For each treatment arm, multivariable regression models were used to evaluate the association between pretreatment expectancy and week 12 pain severity, controlling for baseline pain severity, age, sex, race, and education.

Results

Among 360 participants enrolled, the mean age was 62.1 years (SD 12.7), with 251 (69.7 %) women and 88 (24.4 %) non-white survivors. Pretreatment expectancy was similar for all groups at baseline (EA: 13.9 ± 3.6; BFA: 13.2 ± 3.7, WLC:12.8 ± 3.3, p = 0.14). Greater pretreatment expectancy was not significantly associated with greater pain reduction in any group, after adjusting for co-variates (EA: Coef. = -0.05, 95 % CI = -0.14 - 0.04, p = 0.28; BFA: Coef. = -0.07, 95 % CI = -0.16 - 0.02, p = 0.15; WLC: Coef. = -0.09, 95 % CI = -0.25 - 0.06, p = 0.23).

Conclusions

Pretreatment expectancy did not predict pain reduction for either EA or BFA in cancer survivors. Our study contributes to the interpretation of analgesic effects of EA or BFA, beyond the notion of a mere 'placebo effect'.

Thalamocortical Mechanisms Underlying Real and Imagined Acupuncture

Both acupuncture and imagery have shown potential for chronic pain management. However, the mechanisms underlying their analgesic effects remain unclear. This study aims to explore the thalamocortical mechanisms underlying acupuncture and video-guided acupuncture imagery treatment (VGAIT), a combination of acupuncture and guided imagery, using the resting-state functional connectivity (rsFC) of three thalamic subdivisions-the ventral posterolateral thalamus (VPL), mediodorsal thalamus (MD), and motor thalamus subregion (Mthal)-associated with somatosensory, limbic, and motor circuity. Twenty-seven healthy individuals participated in a within-subject randomized crossover design study. Results showed that compared to sham acupuncture, real acupuncture altered the rsFC between the thalamus and default mode network (DMN) (i.e., mPFC, PCC, and precuneus), as well as the prefrontal and somatosensory cortex (SI/SII). Compared to the VGAIT control, VGAIT demonstrated greater rsFC between the thalamus and key nodes within the interoceptive network (i.e., anterior insula, ACC, PFC, and SI/SII), as well as the motor and sensory cortices (i.e., M1, SMA, and temporal/occipital cortices). Furthermore, compared to real acupuncture, VGAIT demonstrated increased rsFC between the thalamus (VPL/MD/Mthal) and task-positive network (TPN). Further correlations between differences in rsFC and changes in the heat or pressure pain threshold were also observed. These findings suggest that both acupuncture- and VGAIT-induced analgesia are associated with thalamocortical networks. Elucidating the underlying mechanism of VGAIT and acupuncture may facilitate their development, particularly VGAIT, which may be used as a potential remote-delivered pain management approach.