Use of functional MRI to evaluate response to acupuncture

Abstract

Background: Stroke is the 2nd leading cause of death in China and the 3rd leading cause of death in Hong Kong. Stroke is also a leading source of functional disability. Many stroke patients have tried acupuncture to promote functional recovery despite an absence of evidence of effectiveness from well-designed clinical trials. Functional magnetic resonance imaging (fMRI) has been applied by several groups of researchers to map the sites of brain activation during acupuncture stimulation in healthy volunteers. The overall purpose of the present study is to use fMRI to evaluate response to acupuncture in stroke patients. Methods: Brain activations were mapped by fMRI on physiologic tasks with or without stimulation of deficit-related acupoints in healthy volunteers, stroke patients with persistent neurologic deficits, and age-matched healthy control subjects. We tested several acupoints related to motor, language, visual, or sensory dysfunctions. Standard parametric mapping 99 was used in generating the fMRI data. Results: Among healthy volunteers and age-matched controls, our results were similar to those obtained by other research groups. Briefly, stimulation of certain acupoints per se can activate specific brain regions similar in pattern when compared to physiologic tasks. Among stroke patients with persistent neurologic deficits, significant brain activations were seen during electrical stimulation of acupoints implicated in motor, language, or sensory but not visual dysfunctions. In general, activations were seen in the perilesional and homologous sites of stroke patients. Conclusions: Cortical functional reorganization is an important mechanism in functional recovery after stroke. Benefit of acupuncture in stroke patients may be derived from its ability in modulating the activities of the cerebral cortex. Functional MRI may be useful in identifying responders to a course of acupuncture over specific acupoints. Randomized controlled clinical trials are being conducted to test this hypothesis in patients with recent stroke and in stroke patients with persistent neurologic deficits.