Individual-Level Cerebral Blood Flow Responses to Acupuncture Stimulation in Patients with Prolonged Disorders of Consciousness: A Positron Emission Tomography Study

Background: Disorders of consciousness (DoC) remain a major clinical challenge and are characterized by marked heterogeneity in brain injury patterns, which complicates the detection of stimulus-related brain responses at the group level. Although acupuncture has been clinically applied in this population, its cerebral blood flow (CBF) responses at the individual level remain poorly characterized. Objective: To investigate individual CBF responses to acupuncture stimulation in patients with DoC using H 2 15 O positron emission tomography (PET). Methods: Eleven patients with DoC underwent H 2 15 O PET during a block design consisting of acupuncture stimulation at GV26 and rest. Ten patients were included in the final activation analyses. Single-subject analyses were performed using statistical parametric mapping to identify stimulus-related activations. Given lesion heterogeneity and the spatial resolution of PET, peak-level inference was applied at p < 0.001 (uncorrected), and activation patterns were summarized across predefined regions of interest using a region-based frequency approach. Results: At the individual level, acupuncture elicited significant activations in a subset of patients. Activated regions most frequently involved anterior and medial frontal regions, including the anterior cingulate cortex, medial prefrontal cortex, and dorsolateral prefrontal cortex, as well as posterior midline regions. Subcortical activations, including the thalamus and striatum, were observed in some patients. No region was consistently activated across all cases, and marked interindividual variability was present. Conclusions: Acupuncture stimulation at GV26 elicited measurable CBF responses in consciousness-related brain regions in a subset of patients with DoC, despite the absence of significant group-level effects. Trials Registration: UMIN000017520.