Impact of bilateral subthalamic stimulation on motor/cognitive functions in Parkinson's disease

Effects of STN-DBS on cognition and mood in young-onset Parkinson's disease: a two-year follow-up

BACKGROUND

The effects of subthalamic nucleus deep brain stimulation (STN-DBS) on the cognition and mood of patients with PD are still not uniformly concluded, and young-onset Parkinson's disease (YOPD) is even less explored.

OBJECTIVE

To observe the effectiveness of STN-DBS on the cognition and mood of YOPD patients.

METHODS

A total of 27 subjects, with a mean age at onset of 39.48 ± 6.24 and age at surgery for STN-DBS of 48.44 ± 4.85, were followed up preoperatively and for 2 years postoperatively. Using the Unified Parkinson disease rating scale (UPDRS), H&Y(Hoehn and Yahr stage), 39-Item Parkinson's Disease Questionnaire (PDQ-39), Mini-mental state examination (MMSE), Montreal Cognitive Assessment (MoCA), Hamilton depression scale (HAMD), Hamilton anxiety scale (HAMA) to assess motor, cognition, and mood.

RESULTS

At the 2-year follow-up after STN-DBS, YOPD patients showed significant improvements in motor and quality of life (UPDRS III: p < 0.001, PDQ-39: p < 0.001); overall cognition was not significantly different from preoperative (MMSE: p = 0.275, MoCA: p = 0.913), although language function was significantly impaired compared to preoperative (MMSE: p = 0.004, MoCA: p = 0.009); depression and anxiety symptoms also improved significantly (HAMD: p < 0.001, HAMA: p < 0.001) and the depression score correlated significantly with motor (preoperative: r = 0.493, p = 0.009), disease duration (preoperative: r = 0.519, p = 0.006; postoperative: r = 0.406, p = 0.036) and H&Y (preoperative: r = 0.430, p = 0.025; postoperative: r = 0.387, p = 0.046); total anxiety scores were also significantly correlated with motor (preoperative: r = 0.553, p = 0.003; postoperative: r = 0.444, p = 0.020), disease duration (preoperative: r = 0.417, p = 0.031), PDQ-39 (preoperative: r = 0.464, p = 0.015) and H&Y (preoperative: r = 0.440, p = 0.022; postoperative: r = 0.526, p = 0.005).

CONCLUSION

STN-DBS is a safe and effective treatment for YOPD. The mood improved significantly, and overall cognition was not impaired, were only verbal fluency decreased but did not affect the improvement in quality of life.

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

Introduction

Parkinson’s disease (PD) patients have a significantly higher risk of developing dementia in later disease stages, leading to severe impairments in quality of life and self-functioning. Questions remain on how deep brain stimulation (DBS) affects cognition, and whether we can individualize therapy and reduce the risk for adverse cognitive effects. Our aim in this systematic review is to assess the current knowledge in the field and determine if the findings could influence clinical practice.

Methods

We have conducted a systematic review according to PRISMA guidelines through MEDLINE and Embase databases, with studies being selected for inclusion via a set inclusion and exclusion criteria.

Results

Sixty-seven studies were included in this systematic review according to the selected criteria. This includes 6 meta-analyses, 18 randomized controlled trials, 17 controlled clinical trials, and 26 observational studies with no control arms. The total number of PD patients encompassed in the studies cited in this review is 3677, not including the meta-analyses.

Conclusion

Cognitive function in PD patients can deteriorate, in most cases mildly, but still impactful to the quality of life. The strongest evidence is present for deterioration in verbal fluency, while inconclusive evidence is still present for executive function, memory, attention and processing speed. Global cognition does not appear to be significantly impacted by DBS, especially if cognitive screening is performed prior to the procedure, as lower baseline cognitive function is connected to poor outcomes. Further randomized controlled studies are required to increase the level of evidence, especially in the case of globus pallidus internus DBS, pedunculopontine nucleus DBS, and the ventral intermediate nucleus of thalamus DBS, and more long-term studies are required for all respective targets.

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

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.

How is cognition in subthalamic nucleus deep brain stimulation Parkinson's disease patients?

The impairments in cognitive functions such as memory, executive function, visuospatial skills and language in Parkinson's disease (PD) are drawing increasing attention in the current literature. Studies dedicated to investigating the relationship between subthalamic nucleus deep brain stimulation (STN-DBS) and cognitive functioning are contradictory. This systematic review aims to analyze the impact on the cognitive functioning of patients with PD and STN-DBS. Articles published in the 2007-2017 period were retrieved from the Medline/Pubmed databases using PRISMA criteria. The analysis of 27 articles revealed many conflicting results, precluding a consensus on a cognitive functioning standard and hampering the establishment of a neuropsychological profile for PD patients who underwent STN-DBS surgery. Further studies investigating this relationship are needed.

Systematic review of neuropsychological instruments used in subthalamic nucleus deep brain stimulation in Parkinson´s disease patients

In addition to drug treatment, surgical intervention represents an alternative to PD patients with motor deficits. The most common intervention is subthalamic nucleus deep brain stimulation (STN-DBS). It is extremely important to perform a neuropsychological assessment in patients with STN-DBS, not only to identify losses related to the disease, but also to compare influence on cognition both pre and postoperatively.

OBJECTIVE

the objective of this systematic review was to investigate the instruments frequently used in studies related to STN-DBS in PD patients.

METHODS

articles were retrieved from Medline/Pubmed databases published in the 2007-2017 period using PRISMA criteria.

RESULTS

after analyzing 27 articles, the absence of a specific evaluation protocol for PD with STN-DBS was evident.

CONCLUSION

non-motor symptoms are not given due importance in neuropsychological assessments. It is crucial to acknowledge that these symptoms have a major impact on the quality of life of patients. Greater engagement in assessing these aspects is required, in order to bridge the gaps in research.

Cognitive Impact of Deep Brain Stimulation on Parkinson's Disease Patients

Subthalamic nucleus (STN) or globus pallidus interna (GPi) deep brain stimulation (DBS) is considered a robust therapeutic tool in the treatment of Parkinson's disease (PD) patients, although it has been reported to potentially cause cognitive decline in some cases. We here provide an in-depth and critical review of the current literature regarding cognition after DBS in PD, summarizing the available data on the impact of STN and GPi DBS as monotherapies and also comparative data across these two therapies on 7 cognitive domains. We provide evidence that, in appropriately screened PD patients, worsening of one or more cognitive functions is rare and subtle after DBS, without negative impact on quality of life, and that there is very little data supporting that STN DBS has a worse cognitive outcome than GPi DBS.