Deep Brain Stimulation in Parkinson Disease: A Meta-analysis of the Long-term Neuropsychological Outcomes

Abstract

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) or globus pallidum internus (GPi) improves motor functions in patients with Parkinson’s disease (PD) but may cause a decline in specific cognitive domains. The aim of this systematic review and meta-analysis was to assess the long-term (1–3 years) effects of STN or GPi DBS on four cognitive functions: (i) memory (delayed recall, working memory, immediate recall), (ii) executive functions including inhibition control (Color-Word Stroop test) and flexibility (phonemic verbal fluency), (iii) language (semantic verbal fluency), and (iv) mood (anxiety and depression). Medline and Web of Science were searched, and studies published before July 2021 investigating long-term changes in PD patients following DBS were included. Random-effects model meta-analyses were performed using the R software to estimate the standardized mean difference (SMD) computed as Hedges’ g with 95% CI. 2522 publications were identified, 48 of which satisfied the inclusion criteria. Fourteen meta-analyses were performed including 2039 adults with a clinical diagnosis of PD undergoing DBS surgery and 271 PD controls. Our findings add new information to the existing literature by demonstrating that, at a long follow-up interval (1–3 years), both positive effects, such as a mild improvement in anxiety and depression (STN, Hedges’ g = 0,34, p = 0,02), and negative effects, such as a decrease of long-term memory (Hedges’ g = -0,40, p = 0,02), verbal fluency such as phonemic fluency (Hedges’ g = -0,56, p < 0,0001), and specific subdomains of executive functions such as Color–Word Stroop test (Hedges’ g = -0,45, p = 0,003) were observed. The level of evidence as qualified with GRADE varied from low for the pre- verses post-analysis to medium when compared to a control group.

Deep brain stimulation for Parkinson's disease

“…In some centres, a cutoff age for this procedure was decided at an age of 69-70 years. The third criterium for good outcome was a good cognition because it has been reported that cognitive decline could be exacerbated following STN DBS [71,72]; hence all patients referred for DBS undergo a neuropsychologic test to evaluate cognitive skills including memory and executive function. Finally, the last criteria is related to the mood of the patient, which should be formally evaluated in order to avoid performing STN DBS in patients with relevant or untreated depression.…”

Impacts of motor phenotype on cognitive function in patients with Parkinson's disease 1 year after subthalamic‐nucleus deep brain stimulation

“…21 The results of the present study showed a significant effect on memory in PD patients treated with STN-DBS, consistent with the findings of an earlier report. 22 Implicit memory is defined as the acquisition of knowledge that occurs without conscious recollection, and it is critical for cognitive function. Implicit memory was more severely affected in the PIGD group compared with TD patients (Fig.…”

Should we offer deep brain stimulation to Parkinson’s disease patients with GBA mutations?

“…However, there is still uncertainty about how DBS can negatively impact cognition and behavior in some patients. It has been suggested that in some instances, neurosurgical implantation can be detrimental, especially in patients with presurgical cognitive impairment (18). A prospective study assessing motor and nonmotor outcomes of PD-GBA1 treated either with STN-or GPi-DBS and stratified for the different variants is warranted.…”