Table 3.

The neural circuit mechanisms of acupuncture for Parkinson's disease in clinical researches.

Study	Clinical trial design	Clinical condition	Intervention	Comparison	Acupoints	Acupuncture parameters	Outcomes
Chae et al. (2009) [98]	Controlled trial	PD patients (mild)	Verum acupuncture (n = 10)	Covert placebo/overt placebo (n = 10)	Left GB34	10 mm, manually rotated clockwise and counterclockwise once per second (1 Hz), 60 seconds, then withdrawn for 120 seconds, only once	The putamen and the primary motor cortex↑, motor function↑ (VA vs. CP)
Yeo et al. (2012) [99]	RCT	Idiopathic PD patients	Acupuncture (n = 12)	Acupuncture on healthy participants (n = 12)	Right GB34	1 cm, remained in the skin for 1 min and rotated bidirectionally for 1 min, needle remained in the skin without rotation for 1 min and then the pattern of 1 min rotation and 1 min rest was repeated, only once	Neural responses in the SN, caudate, thalamus, and putamen (impaired caused by PD)↑
Yeo et al. (2014) [100]	RCT	Idiopathic PD patients	Acupuncture (n = 12)	Acupuncture on healthy participants (n = 12)	Right GB34	1 cm, for “stimulated” blocks: rotated bidirectionally at 1 Hz; for “not stimulated” blocks: the needle was only inserted into the skin and then left in place, only once	Neural responses in the prefrontal cortex, precentral gyrus, and putamen in PD patients↑
Li et al. (2018) [101]	Controlled trial	PD patients with tremor	Acupuncture+L-DOPA (n = 14)	Sham acupuncture+L-DOPA (n = 14)	DU20, bilateral GB20, and the chorea-tremor controlled zone	2-3 cm, reinforcing-reducing method, twirling every 10 minutes, 30 minutes, twice weekly, 12 weeks	Clinical evaluation: UPDRS (II and III) scores↓, neural responses (SN, caudate, thalamus, and putamen)↑
Huang et al. (2010) [102]	RCT	PD patients	Acupuncture+L-DOPA (n = 5)	L-DOPA (n = 5)	Bilateral MS6, MS4, MS8, MS9, MS14	Continuous wave, 50 Hz, 2-4 mA, 30 minutes, six times a week, 5 weeks	rCBF (the frontal lobe, the occipital lobe, the basal ganglion, and the cerebellum in the most affected hemisphere)↑
Huang et al. (2009) [103]	RCT	PD patients	Acupuncture+Madopar (n = 5)	Madopar (n = 5)	Bilateral MS6, MS4, MS8, MS9, MS14	Continuous wave, 50 Hz, 2–4 mA, 30 minutes, six times a week, 5 weeks	The glucose metabolisms (parietal, temporal, occipital lobes, the thalamus, and the cerebellum in the light-diseased hemisphere, and in parietal and occipital lobes of the severe-diseased hemisphere)↑

PD: Parkinson's disease; GB34: Yanglingquan; VA: verum acupuncture; CP: covert placebo; RCT: randomized controlled trial; SN: substantia nigra; L-DOPA: levodopa; DU20: Baihui; GB20: Fengchi; UPDRS: Unified Parkinson's Disease Rating Scale; MS6: the anterior oblique line of the vertex to temple; MS4: the lateral line III on forehead; MS8: the lateral line I of the vertex; MS9: the lateral line II of the vertex; MS14: the lower-lateral line of the occipital scalp; rCBF: regional cerebral blood flow.