Effects of Deep Brain Stimulation in the Subthalamic Nucleus on Neurocognitive Function in Patients With Parkinson's Disease Compared With Medical Therapy: A Meta-Analysis

Abstract

Background: DBS has been shown to significantly affect motor symptoms in Parkinson's disease (PD). However, some studies have suggested that it may have adverse effects on patients' neurocognitive function. To clarify this operation's effect on neurocognitive function, we collected studies containing neurocognitive function evaluation for qualitative and quantitative analysis.Methods: We searched relevant clinical studies through Pubmed and Embase databases and extracted and sorted out information such as sample size, post-operative scores, pre-operative and post-operative evaluation interval, PD course, and exclusion criteria, from articles meeting the standards. The magnitude and variance of the DBS group's combined effects and the drug therapy group in each neurocognitive domain were calculated and analyzed by the random-effects model.Results: Compared with the drug treatment group, the verbal fluency of patients in the experimental group was significantly decreased at least moderately (ES = −0.553), in which the phonemic fluency declines greatly (ES = −0.842), learning and memory ability was slightly decreased (ES = −0.305), and other neurocognitive functions were not significantly decreased.Conclusion: STN-DBS can affect verbal fluency and damage learning and memory. There was no significant correlation between the above effects and disease progression itself, and it was more likely to be associated with STN-DBS. It is suggested that post-operative patients should be trained and evaluated regularly for their verbal fluency and learning and memory ability. The safety of STN-DBS is acceptable for the majority of patients with motor symptoms.

Cognitive Impact of Deep Brain Stimulation in Parkinson’s Disease Patients: A Systematic Review

“…A prior meta-analysis and an observational study involving solely STN-DBS patients reported no significant differences in processing speed (Castelli et al, 2006;Parsons et al, 2006), while one study found that STN-DBS improves reaction times (Temel et al, 2006). Similar results were found in two recent meta-analyses and a controlled clinical trial comparing STN-DBS and BMT control patients (Williams et al, 2011;Xie et al, 2016;Wang et al, 2021). Slightly worse performance on testing has been found in STN-DBS patients compared to GPi-DBS patients in several studies (Combs et al, 2015;Tan et al, 2016;Wang et al, 2016).…”

“…The cognitive domain of memory was assessed in numerous studies, with conflicting results. Meta-analyses generally point to a slight decline in working and general memory mostly in STN-DBS patients compared to GPi-DBS and BMT patients (Combs et al, 2015;Wang et al, 2016;Xie et al, 2016), with only a study by Wang et al (2021) showing no significant changes, but a trend of worsening in STN-DBS patients compared with BMT. More conflicting findings are found in randomized controlled trials and controlled clinical trials, with slightly fewer studies finding worsening of memory and intact learning (Smeding et al, 2006;York et al, 2008;Weaver et al, 2009Weaver et al, , 2012Rothlind et al, 2015), and no changes compared to BMT controls or between STN-DBS and GPi-DBS patients (Gironell et al, 2003;Zangaglia et al, 2009;Castelli et al, 2010;Daniels et al, 2010;Merola et al, 2011Merola et al, , 2014Sáez-Zea et al, 2012;Tramontana et al, 2015;Boel et al, 2016;Foki et al, 2017).…”

“…Changes in language were the most reported in numerous studies. Looking at meta-analyses, statistically significant decline in semantic and phonemic fluency was found in STN-DBS patients compared to BMT (Xie et al, 2016;Wang et al, 2021) patients and GPi-DBS patients (Combs et al, 2015;Tan et al, 2016;Wang et al, 2016), as well as a part of the natural disease progression with no control arms (Parsons et al, 2006). The decline of verbal fluency was detected in several randomized controlled trials in the STN-DBS groups (Wojtecki et al, 2006;Witt et al, 2008;Okun et al, 2009;Weaver et al, 2009;Zahodne et al, 2009b;Daniels et al, 2010;Phillips et al, 2012;Ehlen et al, 2014;Pinto et al, 2014;Tramontana et al, 2015), although this was not seen in all studies that compared STN-DBS to BMT or GPi-DBS (York et al, 2008;Daniels et al, 2010;Odekerken et al, 2013Odekerken et al, , 2015Odekerken et al, , 2016Rothlind et al, 2015;Boel et al, 2016).…”

“…Worsening of executive functions was seen in two studies, one comparing STN-DBS and GPi-DBS (Combs et al, 2015) and the other comparing STN-DBS to BMT control patients (Xie et al, 2016). On the other hand, two meta-analysis comparing STN-DBS and GPi-DBS (Tan et al, 2016;Wang et al, 2016), one that compared STN to BMT control patients (Wang et al, 2021), and lastly a single meta-analysis covering only STN-DBS patients found no significant alterations in executive function (Parsons et al, 2006).…”

“…Results of cognitive testing in the domain of attention are not frequently reported in studies. One meta-analysis comparing STN-DBS to BMT and one study with only STN-DBS patients found no significant change in DBS patients (Parsons et al, 2006;Xie et al, 2016;Wang et al, 2021). Some slight changes were observed comparing STN-DBS to GPi-DBS, with worse results in the STN-DBS groups (Combs et al, 2015;Wang et al, 2016).…”