**1. Introduction**

Parkinson's disease (PD) is a degenerative neurological disorder associated with dopaminergic cell loss in the substantia nigra and other brain structures characterized by several movement symptoms, such as tremor, rigidity, tremor at rest, and postural instability [1]. PD is the second most common neurodegenerative disorder after Alzheimer's dementia. The prevalence of PD is increasing faster than in other neurological diseases [1,2]. The prevalence increases with age, and in most cases, the cause is unknown [3,4]. Approximately 6.1 million people worldwide were diagnosed with PD in 2016, which is more than double that of 1990 [5]. The movement symptoms of PD are managed using a combination of conventional medications, such as levodopa, carbidopa, dopamine agonists, and monoamine oxidase B inhibitors [5]. On the other hand, if levodopa is administered for a long period, treatment may not be continued due to side effects, such as the on-off phenomenon [6]. Levodopa-induced dyskinesia also impairs the quality of life of patients with PD, making effective treatment difficult [7]. In a previous study, more than 40% of

**Citation:** Kwon, M.; Cheong, M.J.; Leem, J.; Kim, T.-h. Effect of Acupuncture on Movement Function in Patients with Parkinson's Disease: Network Meta-Analysis of Randomized Controlled Trials. *Healthcare* **2021**, *9*, 1502. https:// doi.org/10.3390/healthcare9111502

Academic Editors: Manoj Sharma and Kavita Batra

Received: 7 October 2021 Accepted: 2 November 2021 Published: 5 November 2021

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patients with PD experienced wear-off and levodopa-induced dyskinesia, which lowered drug adherence [8]. If conventional drugs are ineffective, several surgical strategies, such as deep brain stimulation (DBS) or radiofrequency ablation, could be considered [9]. However, there are a number of complications associated with a surgical approach, and patient expectations after surgery are sometimes not fulfilled [10]. In addition, as the disease progresses, the burden on caregivers increases because of frequent nursing home visits, longer hospital stays, and higher rates of emergency room visitation [11]. Therefore, in addition to conventional management, alternative therapeutic options are needed to manage various symptoms considering the characteristics of PD, which has a long disease duration.

Recently, various complementary and integrative medicine (CIM) therapies, such as acupuncture, herbal medicine, qi-gong, massage, yoga, meditation, and music therapy, have been widely utilized in clinical practice for PD symptom management [12]. Acupuncture is one of the most commonly used CIM interventions for the management of patients with PD [13]. In previous studies, acupuncture improved motor symptoms, non-motor symptoms, quality of life, and disease progression, and decreased the adverse events and dosage of anti-parkinsonian medication [13]. Several clinical studies and systematic reviews have shown the effects of various types of acupuncture treatment combined with conventional medication on motor symptom improvement using the unified PD rating scale (UPDRS) [14–17].

However, it is unknown which type of acupuncture treatment is the preferred option because the acupuncture treatment applied in each study is different. Most clinical research and systematic reviews have compared two interventions at a time. Multiple intervention comparison research designs are not common. However, in clinical practice, physicians are curious about which treatment is more effective among the various widely used treatments. However, in terms of time and cost, it is difficult to conduct direct comparative (headto-head) studies on various acupuncture treatments, and the need to compare multiple interventions at a time is increasing. Nowadays, a novel methodology named 'network meta-analysis (NMA)' is used to simultaneously estimate the relative effect of various interventions [18,19]. NMA results help stakeholders to make decisions by providing a combined quantitative effect size acquired from direct and indirect comparisons of different interventions [20].

This study aimed to compare the effect on movement symptom improvement in patients with PD about several acupuncture types combined with conventional medication (CM), such as manual acupuncture (MA), electroacupuncture (EA), and bee venom acupuncture (BVA), compared with placebo acupuncture or conventional medication only. We adopted conventional systematic review, pairwise meta-analysis (PMA), and NMA methodology to compare the effect size of various acupuncture types to help with decision making regarding the management of patients with PD.
