Comparison of Subthalamic Nucleus and Globus Pallidus Deep Brain Stimulation in Parkinson s Disease: A Systematic Review

Review Article

Austin Alzheimers J Parkinsons Dis. 2021; 5(1): 1033.

Comparison of Subthalamic Nucleus and Globus Pallidus Deep Brain Stimulation in Parkinson’s Disease: A Systematic Review

Azari H*

Urmia University of Medical Sciences, Urmia, Iran

*Corresponding author: Hushyar Azari, Urmia University of Medical Sciences, Urmia, Iran; Email: [email protected]

Received: August 10, 2021; Accepted: September 09, 2021; Published: September 16, 2021


Background: Deep Brain Stimulation (DBS) is regarded as a viable therapeutic choice for Parkinson’s Disease (PD). The two most common sites for DBS are the Subthalamic Nucleus (STN) and Globus Pallidus (GPi). In this study, the clinical effectiveness of these two targets was compared.

Methods: A systematic literature search in electronic databases were restricted to English language publications 2010 to 2021. Specified MeSH terms were searched in all databases. Studies that evaluated the Unified Parkinson’s Disease Rating Scale (UPDRS) III were selected by meeting the following criteria: (1) had at least three months follow-up period; (2) compared both GPi and STN DBS; (3) at least five participants in each group; (4) conducted after 2010. Study quality assessment was performed using the Modified Jadad Scale.

Results: 3577 potentially relevant articles were identified 3569 were excluded based on title and abstract, duplicate and unsuitable article removal. Eight articles satisfied the inclusion criteria and were scrutinized (458 PD patients). Majority of studies reported no statistically significant between-group difference for improvements in UPDRS III scores.

Conclusions: Although there were some results in terms of action tremor, rigidity, and urinary symptoms, which indicated that STN DBS might be a better choice or regarding the adverse effects, GPi seemed better; but it cannot be concluded that one target is superior. Other larger randomized clinical trials with longer follow-up periods and control groups are needed to decide which target is more efficient for stimulation and imposes fewer adverse effects on the patients.

Keywords: Deep Brain stimulation; Globus pallidus; Parkinson’s disease; Subthalamic nucleus; UPDRS


Parkinson’s disease is the most common movement disorder, the second common progressive, disabling, and neurodegenerative disease, which is expected to be as prevalent as 12.9 million cases by 2040 [1-4]. Although acute diseases such as stroke are decreased in developed countries, neurodegenerative diseases are increasing and affecting most of their population [5]. PD prevalence is estimated at 160 per 100000 in individuals over 65 years old [6]. Parkinson’s disease is characterized by slow movements, rigidity, and low amplitude movements without the previous automaticity. Gait problems are among the most prominent and disabling signs of this disorder which progress as time passes [7]. Various genetic, environmental, lifestylerelated factors and aging have been proposed as the riggers for Parkinson’s disease initiation [8,9]. Classically, Parkinson’s disease is attributed to the progressive death of dopaminergic neurons of basal ganglia and hyperactivity of striatopallidal pathway in the dorsal striatum due to loss of dopamine signaling and presence of Lewy bodies and Lewy neuritis. PD patients suffer from various motor and non-motor symptoms that negatively impact their daily lives [10]. Levodopa, a dopamine precursor, was developed for the first time in 1911 [11]. It has been used as an efficacious drug for PD treatment for over 50 years, but it has been shown that its efficacy declines as the disease progresses [6,12]. Surgical treatment of movement disorders started in 1987 by targeting the ventral intermediate nucleus of the thalamus [13,14] by the DBS technique. DBS is a common and effective surgical treatment option that alleviates motor symptoms. It was introduced about three decades ago and is recently performed on several new targets in the brain, including the Subthalamic nucleus (STN) and Globus Pallidus internus (GPi) [10,15,16]. Performing this technique on the STN and Gpi has proven to be highly effective and safe, but several adverse effects like verbal fluency problems are reported. This is attributed to the stimulation site in some studies [17]. This systematic review investigated the efficacy of STN and GPi deep brain stimulation on UPDRS score outcomes in Parkinson’s disease and its related adverse effects.


Search plan

Potentially relevant English-language articles, published from 2010 to 2021, were recognized by searching in Embase, Cochrane Library, and PubMed databases. We searched for studies including both targets (GPi and STN) and their related aspects. Search terms were deep brain stimulation (DBS) [MeSH term] or in combination with the following keywords: Controlled Clinical Trial [Publication Category], Randomized Controlled Trial [Publication Category], Globus Pallidus internus [MeSH term], Globus Pallidus [MeSH term], GPi [MeSH term], Subthalamic nucleus [MeSH term], STN [MeSH term], and Parkinson’s disease [MeSH term].

Study selection criteria

For this research, we included the clinical studies that (1) contained evaluated unified PD rating scale (UPDRS) III before and after deep brain stimulation; (2) compared GPi-DBS and STNDBS for PD; (3) recruiting more than five subjects in GPi and STN groups; (4) had a description of adverse events; (5) had more than three months of follow-up period; (6) Availability of English full text (7). The selection process took place in two phases: 1) title and the abstract selection; 2) full-text selection. These processes were done by all researchers independently. The full texts of the articles were ordered and compared according to the eligibility criteria. Any disagreements were resolved by discussion.

Data collection

The database was created by gathering the data about study design, efficacy, symptoms, materials, and population. Additionally, different adverse events and UPDRS III scores were extracted from articles.


In total, 3577 potentially related articles were identified from the following databases: 834 studies from Embase, 676 studies from Cochrane Library, and 2067 studies from PubMed. After the primary evaluation, studies with unsuitable titles and abstracts were excluded (3461), duplicate articles were removed (102), 14 articles remained for further assessment.

Two systematic reviews [18,19], two meta-analysis [20,21], and two letters [22,23] were also removed. The full texts of the remaining eight articles were scrutinized (Figure 1).