Cortical hemodynamic responses to acupuncture at Lianquan (CV23) in patients with post-stroke dysphagia: a functional near-infrared spectroscopy study.

INTRODUCTION: Acupuncture at Lianquan (CV23) is an effective intervention for post-stroke dysphagia (PSD); however, the central neural regulatory mechanisms remain unclear. This study used functional near-infrared spectroscopy (fNIRS) with deqi assessment to compare cortical activation during acupuncture at CV23 between PSD patients and healthy controls, and to examine the correlation between deqi intensity and cortical activation. METHODS: In this cross-sectional study, 21 PSD patients (PSD group) and 29 healthy controls (HC group) received acupuncture at CV23. fNIRS was used to monitor hemodynamic responses in the bilateral primary motor cortex (M1), premotor cortex/supplementary motor area (PMC/SMA), dorsolateral prefrontal cortex (DLPFC), supramarginal gyrus (SMG), primary somatosensory cortex (S1), and somatosensory association cortex (SAC) throughout a pre-stimulation baseline and three needle manipulation blocks. Deqi intensity was assessed with a visual analog scale (VAS). In patients with left-hemisphere lesions, fNIRS channels were mirrored to the right side, so "left" and "right" denoted the contralesional and ipsilesional sides. RESULTS: In the PSD group, oxygenated hemoglobin (HbO) concentrations during the needle manipulation period were significantly higher than those at the pre-stimulation baseline in the contralesional M1 (p = 0.040), contralesional SAC (p = 0.040), and contralesional SMG (p = 0.040); meanwhile, deoxygenated hemoglobin (HbR) decreased in the contralesional S1 and SMG (p < 0.05), whereas no significant changes were observed in the HC group. Compared with the HC group, the PSD group exhibited significantly higher HbO concentrations in the contralesional SAC (p = 0.012), contralesional M1 (p = 0.014), contralesional S1 (p = 0.014), contralesional SMG (p = 0.014), and ipsilesional SAC (p = 0.014). The total deqi score, suan (aching or soreness), and zhang (fullness/distention or pressure) were significantly higher in the PSD group (p < 0.05). Significant correlations were observed between deqi sensations and cortical activation in the PSD group, while no significant correlations were observed in the HC group. CONCLUSION: Acupuncture at CV23 in PSD may be associated with altered activation in the contralesional sensorimotor network (M1, S1, SAC, and SMG), and deqi intensity was associated with cortical activation, providing fNIRS evidence for the association between acupuncture and the central mechanisms of PSD.