MacPherson H, Green G, Lythgoe M, Hasselfoot R, Lewith G*, Nevado A, Asghar A.

Neuroimaging the response to acupuncture at LI-4 (Hegu): comparing superficial and deep needling.

University of York, Department of Health Sciences, Seebolm Rowntree Building, Area 4, University of York, Heslington, York, North Yorkshire YO10 5DD, UK. hm18@york.ac.uk *Presenting author

AIMS: Our primary aim was to investigate, using functional magnetic resonance imaging (fMRI), the extent and locations of activations and deactivations of the brain in response to superficial and deep needling at the acupuncture point Hegu (LI-4). Our secondary aim was to explore possible variations in brain images associated with the deqi sensation, which is commonly experienced as a dull ache.

SETTING: York Neuroimaging Centre, University of York, UK.

PARTICIPANTS: Seventeen healthy right-handed volunteers, naïve to acupuncture.

STUDY DESIGN: Participant-blinded randomised block design.

EXPERIMENTAL PARADIGM: Seventeen volunteers received two interventions, one with superficial and one with deep needling, both at Hegu (LI-4), from an experienced acupuncturist. fMRI scans were conducted over two 16 minute periods according to a randomised block design. After each scan, each participant rated their sensations at the site of needling, and these sensations were subsequently assigned into two categories: a deqi associated group and an acute pain-related group.

IMAGING: Scanning was performed with a 3 Tesla GE magnetic resonance imaging system. fMRI analysis, based upon the general linear model, was performed using FSL software. Results are presented in the form of activations (increased blood flow) and deactivations (decreased blood flow) with threshold Z scores of 4.

RESULTS: For our primary analysis, we found more deactivations than activations for both superficial and deep needling, though with different response patterns. While activations were mainly in the cerebellum for both superficial and deep needling, deactivations for superficial needling were mainly in the contralateral hemisphere in the frontal, parietal and temporal lobes. In contrast, deep needling was associated with deactivations mostly in the contralateral occipital lobes. In our secondary analysis exploring the response to different needle sensations, we found that for both superficial and deep needling, deqi was more associated with deactivations whereas acute pain was more associated with activations.

CONCLUSION: Superficial needling is not a good control for deep needling in experimental trials of acupuncture.

 

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