eCAM Advance Access published online on September 30, 2009
eCAM, doi:10.1093/ecam/nep154
Methodological Problems in fMRI Studies on Acupuncture: A Critical Review With Special Emphasis on Visual and Auditory Cortex Activations
1Brain Imaging Center, 2Institute of Neuroradiology, Goethe-University, 3Max-Planck-Institute of Biophysics and 4Department of Neurology, Goethe-University, Frankfurt, Germany
Functional magnetic resonance imaging (fMRI) has been used for more than a decade to investigate possible supraspinal mechanisms of acupuncture stimulation. More than 60 studies and several review articles have been published on the topic. However, till now some acupuncture-fMRI studies have not adopted all methodological standards applied to most other fMRI studies. In this critical review, we comment on some of the problems including the choice of baseline, interpretation of deactivations, attention control and implications of different group statistics. We illustrate the possible impact of these problems by focussing on some early findings, namely activations of visual and auditory cortical areas, when acupoints were stimulated that are believed to have a therapeutic effect on vision or hearing in traditional Chinese medicine. While we are far from questioning the validity of using fMRI for the study of acupuncture effects, we think that activations reported by some of these studies were probably not a direct result of acupuncture stimulation but rather attributable to one or more of the methodological problems covered here. Finally, we try to offer solutions for these problems where possible.
Keywords: acupuncture – default mode network – fMRI – resting state – visual cortex
For reprints and all correspondence: Florian Beissner, Goethe-University Frankfurt, Neuroradiology, Brain Imaging Center, Schleusenweg 2-16, 60528 Frankfurt, Germany. Tel: +49-69-6301-83820; Fax: +49-69-6301-3707; E-mail: beissner{at}med.uni-frankfurt.de
Received June 17, 2009; accepted August 30, 2009