Greater improvement in quality of life following unilateral deep brain stimulation surgery in the globus pallidus as compared to the subthalamic nucleus

Co-Occurrence of Apathy and Impulse Control Disorders in Parkinson Disease: Variation across Multiple Measures

OBJECTIVE

To determine if the co-occurrence of apathy and impulse control disorders (ICDs) in Parkinson disease is dependent on instrument selection and assess the concurrent validity of three motivation measures by examining interrelationships between them.

METHOD

Ninety-seven cognitively normal individuals with idiopathic Parkinson disease (PD) completed the Questionnaire for Impulsive-Compulsive Disorders in Parkinson Disease-Rating Scale (QUIP-RS) and three apathy measures: the Apathy Scale, Lille Apathy Rating Scale, and Item 4 of the Movement Disorder Society-Unified Parkinson Disease Rating Scale.

RESULTS

Fifty (51.5%) participants were classified as apathetic on at least one measure, and only four individuals (4.3%) obtained clinically elevated scores on all three measures. The co-occurrence of apathy and ICD varied across measures.

CONCLUSIONS

We observed a co-occurrence of apathy and ICDs in PD patients with each apathy instrument; however, limited concurrent validity exists across measures. This is important for future investigations into shared pathophysiology and the design of future clinical trials aimed at improving the early detection and treatment of these debilitating syndromes.

Quality of Life after Deep Brain Stimulation in Parkinson's Disease: Does the Target Matter?

BACKGROUND

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) and globus pallidus internus (GPi) is an accepted therapy for Parkinson's disease (PD) with disabling motor complications. For elderly patients with poorer cognition and postural instability, GPi has been proposed as the preferable DBS target based on expert opinion, arguing GPi-DBS may be less complicated by depression, apathy, worsened verbal fluency, and executive dysfunction, resulting in greater improvement in quality of life (QoL). However, data supporting such patient-tailored approach are lacking.

OBJECTIVES

The aims were to analyze whether the DBS target influences QoL in a PD cohort and a matched subgroup of frail patients with poor cognitive status and reduced postural stability, and whether other factors affect the QoL outcomes.

METHODS

In this retrospective study, we analyzed a single-center cohort of 138 PD patients who received bilateral STN-DBS (117) or GPi-DBS (21) using the mentioned approach for target selection. All patients underwent standardized clinical evaluations of motor- and nonmotor signs as well as QoL before and 1 year after surgery.

RESULTS

DBS of both targets improved motor signs, dyskinesias, and pain. QoL improved without significant difference between the targets, but with a trend for greater improvement across all QoL domains in favor of the STN, even in an STN subgroup matched to the GPi group.

CONCLUSION

Our results contradict the prevailing belief that GPi-DBS is superior in frail PD patients with cognitive decline and postural instability, questioning the proposed patient-tailored approach of DBS target selection. Further studies are needed for a data-driven approach.

Impact of Stimulation Frequency on Verbal Fluency Following Bilateral Subthalamic Nucleus Deep Brain Stimulation in Parkinson's Disease

OBJECTIVE

The effects of stimulation frequency on verbal fluency (VF) following subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson's disease (PD) are not well understood. The present study examines the impact stimulation frequency has on VF following bilateral STN-DBS in PD.

METHODS

Prospective study of 38 consecutive patients with PD with low frequency STN-DBS (LFS) (n = 10) and high frequency STN-DBS (HFS) (n = 14), and a non-operated PD control group consisting of patients with fluctuating response to dopaminergic medication (n = 14) homogeneous in age, education, disease duration, and global cognitive function. Patients were evaluated on VF tasks (letter, semantic, action verbs, alternating). A one-way analysis of variance (ANOVA) was conducted to assess distinctions between groups. Pre- and post-surgical comparisons of fluencies were performed for operated groups. A mixed ANOVA was applied to the data to evaluate the interaction between treatment (HFS vs. LFS) and time (pre- vs. post-surgery). Strategy use (clustering and switching) was evaluated.

RESULTS

Semantic and letter fluency performance revealed significant differences between HFS and LFS groups. Pre- and post-surgical comparisons revealed HFS negatively affected letter, semantic, and action fluencies, but LFS had no effect on VF. No interaction effect or main effect of treatment was found. Main effect of time was significant for semantic and action fluencies indicating a decrease in postoperative fluency performance. Patients with LFS produced larger average cluster sizes than patients with HFS.

CONCLUSION

LFS may be less detrimental to VF, but these findings suggest that VF decline following STN-DBS is not caused by stimulation frequency alone.

Cross-Cultural Differences in Stigma Associated with Parkinson's Disease: A Systematic Review

BACKGROUND

Stigma is an important social attitude affecting the quality of life (QoL) of people with Parkinson's disease (PwP, PD) as individuals within society.

OBJECTIVE

This systematic review aimed to 1) identify the factors associated with stigma in PD and 2) demonstrate culture-based diversity in the stigmatization of PwP. We also reported data from the Turkish PwP, which is an underrepresented population.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, a literature search of the PubMed/Medline electronic database was performed covering the last 26 years. Articles on self-perceived stigma in PD with a sample size >  20 and quantitative results were included. Data were extracted by independent reviewers.

RESULTS

After screening 163 articles, 57 were eligible for review, most of which were from Europe or Asia. Only two studies have been conducted in South America. No study from Africa was found. Among the 61 factors associated with stigma, disease duration, sex, and age were most frequently studied. A comparison of the investigated factors across the world showed that, while the effect of motor impairment or treatment on stigma seems to be culture-free, the impact of sex, education, marriage, employment, cognitive impairment, and anxiety on stigma may depend on culture.

CONCLUSION

The majority of the world's PD population is underrepresented or unrepresented, and culture may influence the perception of stigma in PwP. More diverse data are urgently needed to understand and relieve the challenges of PwP within their society.

Deep Brain Stimulation in the Treatment of Parkinson’s Disease

Parkinson’s disease (PD) is a common progressive neurodegenerative movement disorder. The cardinal feature of Parkinson's is neuronal degeneration causing a dopamine deficit in the brain which leads to a host of clinical features in the patient. However, consensus over specific clinical criteria for diagnosis remains to be established. Parkinson’s does not have a cure yet, but a variety of diagnostic and treatment protocols have been developed over the years with a primary focus on pharmacological therapy. Anti-parkinsonian drugs such as levodopa lose their efficacy over time and are needed in higher doses as the disease inevitably progresses. An alternative to pharmacological therapy is deep brain stimulation (DBS). Deep brain stimulation involves transcranial placement of unilateral or bilateral leads (wires) most commonly in the sub-thalamic nucleus or the globus pallidus interna of the brain by stereotactic surgery. Given the multiple hypotheses explaining the different effects of DBS with sometimes conflicting mechanisms, it is difficult to pinpoint the exact way in which DBS operates. Nevertheless, it has proven to be significantly effective. DBS, although being a cost-effective treatment measure for Parkinson's patients, is not without limitations. A careful selection of patients is required preoperatively that determines the response and tolerance to the therapy in patients. This review aims to summarize the current literature on DBS in Parkinson's with a focus on the hypothesized mechanisms, selection criteria, advantages and its limitations.

Device-Assisted and Neuromodulatory Therapies for Parkinson's Disease: A Network Meta-Analysis

BACKGROUND

Device-assisted and neuromodulatory therapies are the standard of care for Parkinson's disease (PD) with disabling motor complications. We aimed to compare and rank the currently available advanced therapies for PD on patient relevant outcomes.

METHODS

We searched various databases for randomized controlled trials that studied subthalamic nucleus deep brain stimulation (STN-DBS), globus pallidus interna (GPi) DBS, pallidotomy, subthalamotomy, continuous subcutaneous apomorphine infusion (CSAI), or intrajejunal levodopa infusion (IJLI), in patients with PD and motor complications. Primary outcome was the quality of life (QOL) at 6 months. Secondary outcomes included Unified Parkinson's Disease Rating Scale III and II, ON time, OFF time, levodopa equivalent daily doses, and adverse events (AE). Data were pooled using a Bayesian network meta-analysis, summarized as mean difference (MD) with 95% credibility intervals (CrI) and visualized in forest plots/league tables. Surface under the cumulative ranking curve plots determined the ranking probability.

RESULTS

We identified 6745 citations and included 26 trials. STN-DBS (MD, -8.0; 95% CrI, -11, -5.8), GPi-DBS (MD, -7.1; 95% CrI, -11, -2.9), and IJLI (MD, -7.0; 95% CrI, -12, -1.8) led to better QOL than medical therapy alone, without significant differences among them. STN-DBS had the highest probability of being ranked the best treatment for QOL (79.6%), followed by IJLI (63.5%) and GPi-DBS (62.8%).

CONCLUSIONS

In advanced PD, STN-DBS alleviates more patient and clinician relevant outcomes, followed by GPi-DBS and IJLI. In resource limited settings, unilateral pallidotomy may improve motor symptoms and activities of daily living, although overall QOL may not be improved. © 2022 International Parkinson and Movement Disorder Society.

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.

Unilateral GPi-DBS Improves Ipsilateral and Axial Motor Symptoms in Parkinson’s Disease as Evidenced by a Brain Perfusion Single Photon Emission Computed Tomography Study

Introduction

Deep brain stimulation (DBS) is an effective treatment for advanced Parkinson’s disease (PD) with the targeting bilateral subthalamic nucleus or globus pallidus internus (STN or GPi-DBS). So far, detailed studies on the efficacy of unilateral STN-DBS for motor symptoms have been reported, but few studies have been conducted on unilateral GPi-DBS.

Materials and Methods

Seventeen patients with Parkinson’s disease (PwPD) who underwent unilateral GPi-DBS were selected. We conducted comparison analyses between scores obtained 6–42 months pre- and postoperatively using the following measurement tools: the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) part III, the Hoehn and Yahr stage, the presence/absence of dyskinesia, Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB), Geriatric Depression Scale (GDS), levodopa equivalent dose (LED), and cerebral blood flow by single photon emission computed tomography (SPECT). Patient backgrounds were compared between four cohorts with favorable (good responders, ≥50% improvement) and unfavorable (poor responders, <50% improvement) postoperative outcome.

Results

Significant improvement was observed postoperatively in the following: total MDS-UPDRS Part III scores during the off period, contralateral scores, ipsilateral scores, and axial scores. Similarly, the Hoehn and Yahr stages during the off period, and GDS also showed significant decrease. In contrast, LED, MMSE, and FAB remained unchanged while the number of patients who scored positive for dyskinesia decreased by 40%. Abnormal cerebral blood flow preoperatively seen in the cerebral cortex had normalized in the total score-based good responder cohort. In the ipsilateral score-based good responder cohort, cerebral blood flow increased in the contralateral frontal lobe including in the premotor cortex, contralateral to the DBS. Compared to the poor responders, postoperative good responders demonstrated significantly higher preoperative MMSE scores.

Discussion

Unilateral GPi-DBS therapy was effective in improving contralateral, ipsilateral, and axial motor symptoms of patients with advanced PD; in particular, it was found to be especially beneficial in PwPD whose cognitive function was unimpaired; the treatment efficacy rivaled that of bilateral counterparts up till at least 6 months postoperatively. Finally, normalization of preoperative abnormalities in cerebral blood flow and increased cerebral blood flow in the contralateral frontal lobe indicated the beneficial potential of this therapy on ipsilateral motor symptoms.

Effects of Unilateral Stimulation in Parkinson's Disease: A Randomized Double-Blind Crossover Trial

Introduction

Previous studies have shown that subthalamic nucleus (STN) and unilateral globus pallidus interna (GPi) are similarly effective in the deep brain stimulation (DBS) treatment of motor symptoms. However, the counterintuitively more common clinical application of STN DBS makes us hypothesize that STN is superior to GPi in the treatment of motor symptoms.

Methods

In this prospective, double-blind, randomized crossover study, idiopathic PD patients treated with combined unilateral STN and contralateral GPi DBS (STN in one brain hemisphere and GPi in the other) for 2 to 3 years were enrolled. The MDS UPDRS-III total score and subscale scores for axial and bilateral limb symptoms were assessed preoperatively and at 2- to 3-year follow-up in four randomized, double-blinded conditions: (1) Med–STN+GPi–, (2) Med–STN–GPi+, (3) Med+STN+GPi–, and (4) Med+STN–GPi+.

Results

Eight patients had completed 30 trials of assessment. Compared with the preoperative Med– state, in the Med–STN+GPi– condition, the cardinal symptoms in both sides of the body were all improved. In the Med–STN–GPi+ condition, symptoms of the GPi-stim limb were improved, while only tremor was improved on the ipsilateral side, although all axial symptoms showed aggravation. Compared with the preoperative Med+ state, in the Med+STN+GPi– state, cardinal symptoms were improved on both sides, except that tremor was worsened on the STN-stim side. In the Med+STN–GPi+ state, the overall motor symptoms were aggravated compared with the preoperative Med+ state. Most axial symptoms worsened at acute unilateral STN or GPi DBS onset, compared to both preoperative Med– and Med+ states. No side effects associated with this study were seen.

Conclusions

Improvement in motor symptoms was greater in all sub-scores favoring STN. The effects of STN+ were seen on both sides of the body, while GPi+ mainly acted on the contralateral side.

Development of standardized regression-based formulas to assess meaningful cognitive change in early Parkinson's disease

OBJECTIVE

Longitudinal assessment of cognitive and emotional functioning in patients with Parkinson's disease (PD) is helpful in tracking progression of the disease, developing treatment plans, evaluating outcomes, and educating patients and families. Determining whether change over time is meaningful in neurodegenerative conditions, such as PD, can be difficult as repeat assessment of neuropsychological functioning is impacted by factors outside of cognitive change. Regression-based prediction formulas are one method by which clinicians and researchers can determine whether an observed change is meaningful. The purpose of the current study was to develop and validate regression-based prediction models of cognitive and emotional test scores for participants with early-stage idiopathic PD and healthy controls (HC) enrolled in the Parkinson's Progression Markers Initiative (PPMI).

METHODS

Participants with de novo PD and HC were identified retrospectively from the PPMI archival database. Data from baseline testing and 12-month follow-up were utilized in this study. In total, 688 total participants were included in the present study (NPD = 508; NHC = 185). Subjects from both groups were randomly divided into development (70%) and validation (30%) subsets.

RESULTS

Early-stage idiopathic PD patients and healthy controls were similar at baseline. Regression-based models were developed for all cognitive and self-report mood measures within both populations. Within the validation subset, the predicted and observed cognitive test scores did not significantly differ, except for semantic fluency.

CONCLUSIONS

The prediction models can serve as useful tools for researchers and clinicians to study clinically meaningful cognitive and mood change over time in PD.

Globus Pallidus Internus (GPi) Deep Brain Stimulation for Parkinson's Disease: Expert Review and Commentary

INTRODUCTION

The globus pallidus internus (GPi) region has evolved as a potential target for deep brain stimulation (DBS) in Parkinson's disease (PD). DBS of the GPi (GPi DBS) is an established, safe and effective method for addressing many of the motor symptoms associated with advanced PD. It is important that clinicians fully understand this target when considering GPi DBS for individual patients.

METHODS

The literature on GPi DBS in PD has been comprehensively reviewed, including the anatomy, physiology and potential pitfalls that may be encountered during surgical targeting and post-operative management. Here, we review and address the implications of lead location on GPi DBS outcomes. Additionally, we provide a summary of randomized controlled clinical trials conducted on DBS in PD, together with expert commentary on potential applications of the GPi as target. Finally, we highlight future technologies that will likely impact GPi DBS, including closed-loop adaptive approaches (e.g. sensing-stimulating capabilities), advanced methods for image-based targeting and advances in DBS programming, including directional leads and pulse shaping.

RESULTS

There are important disease characteristics and factors to consider prior to selecting the GPi as the DBS target of PD surgery. Prior to and during implantation of the leads it is critical to consider the neuroanatomy, which can be defined through the combination of image-based targeting and intraoperative microelectrode recording strategies. There is an increasing body of literature on GPi DBS in patients with PD suggesting both short- and long-term benefits. Understanding the GPi target can be useful in choosing between the subthalamic (STN), GPi and ventralis intermedius nucleus as lead locations to address the motor symptoms and complications of PD.

CONCLUSION

GPi DBS can be effectively used in select cases of PD. As the ongoing DBS target debate continues (GPi vs. STN as DBS target), clinicians should keep in mind that GPi DBS has been shown to be an effective treatment strategy for a variety of symptoms, including bradykinesia, rigidity and tremor control. GPi DBS also has an important, direct anti-dyskinetic effect. GPi DBS is easier to program in the outpatient setting and will allow for more flexibility in medication adjustments (e.g. levodopa). Emerging technologies, including GPi closed-loop systems, advanced tractography-based targeting and enhanced programming strategies, will likely be future areas of GPi DBS expansion. We conclude that although the GPi as DBS target may not be appropriate for all PD patients, it has specific clinical advantages.

Cortical hemodynamic mapping of subthalamic nucleus deep brain stimulation in Parkinsonian patients, using high-density functional near-infrared spectroscopy

Subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment for idiopathic Parkinson's disease. Despite recent progress, the mechanisms responsible for the technique's effectiveness have yet to be fully elucidated. The purpose of the present study was to gain new insights into the interactions between STN-DBS and cortical network activity. We therefore combined high-resolution functional near-infrared spectroscopy with low-resolution electroencephalography in seven Parkinsonian patients on STN-DBS, and measured cortical haemodynamic changes at rest and during hand movement in the presence and absence of stimulation (the ON-stim and OFF-stim conditions, respectively) in the off-drug condition. The relative changes in oxyhaemoglobin [HbO], deoxyhaemoglobin [HbR], and total haemoglobin [HbT] levels were analyzed continuously. At rest, the [HbO], [HbR], and [HbT] over the bilateral sensorimotor (SM), premotor (PM) and dorsolateral prefrontal (DLPF) cortices decreased steadily throughout the duration of stimulation, relative to the OFF-stim condition. During hand movement in the OFF-stim condition, [HbO] increased and [HbR] decreased concomitantly over the contralateral SM cortex (as a result of neurovascular coupling), and [HbO], [HbR], and [HbT] increased concomitantly in the dorsolateral prefrontal cortex (DLPFC)-suggesting an increase in blood volume in this brain area. During hand movement with STN-DBS, the increase in [HbO] was over the contralateral SM and PM cortices was significantly lower than in the OFF-stim condition, as was the decrease in [HbO] and [HbT] in the DLPFC. Our results indicate that STN-DBS is associated with a reduction in blood volume over the SM, PM and DLPF cortices, regardless of whether or not the patient is performing a task. This particular effect on cortical networks might explain not only STN-DBS's clinical effectiveness but also some of the associated adverse effects.

The Effect of Deep Brain Stimulation on Swallowing Function in Parkinson's Disease: A Narrative Review

Unlike appendicular motor symptoms, such as bradykinesia and rigidity, in Parkinson's disease (PD), which have already been reported to respond well to deep brain stimulation (DBS), there is limited literature on the effects of DBS on swallowing function in patients with PD. The field lacks consensus as there are conflicting reports among existing studies regarding whether swallowing function improves or declines following DBS implantation. This narrative review aims to summarize and analyze the studies published on the effect of DBS on swallowing function in patients with PD. We collated studies published up to February 2020 using a comprehensive electronic database search of PubMed, SCOPUS, EMBASE, and the Cochrane Library. Two reviewers independently assessed the studies using strict inclusion and exclusion criteria. The primary literature search yielded 529 relevant papers. After reading their titles and abstracts and assessing their eligibility based on the full-text, we finally included and reviewed 14 publications. Nine of these studies reported positive effects of DBS on swallowing function and four studies showed no significant positive results. The remaining study showed decreased swallowing function after unilateral subthalamic nucleus-DBS surgery. In conclusion, we found that DBS has the potential to improve swallowing function in patients with PD. However, high-quality evidence is lacking. To clearly elucidate the effect of DBS on swallowing function in patients with PD, high-quality randomized controlled trials should be conducted in the future.

Parkinson Disease-Related Pattern of Glucose Metabolism Associated With the Potential for Motor Improvement After Deep Brain Stimulation

BACKGROUND

Motor dysfunctions in Parkinson disease (PD) patients are not completely normalized by deep brain stimulation (DBS), and there is an obvious difference in the degree of symptom improvement after DBS for each patient.

OBJECTIVE

To test our hypothesis that each patient has their own restoration capacity for motor improvement after DBS, and to investigate whether regional cerebral glucose metabolism in 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans is associated with the capacity for off-medication motor improvement (MIoff) after DBS.

METHODS

The MIoff (%) was calculated using the Unified Parkinson's Disease Rating Scale part III in 27 PD patients undergoing DBS in the globus pallidus interna. The standardized uptake value ratios (SUVRs) on FDG-PET were quantitatively measured, and the areas where the SUVR correlated with the MIoff (%) were identified. Also, the areas where the SUVR was significantly different between the 2 MIoff groups (≥60% vs <60%) were determined.

RESULTS

Ten patients achieved MIoff > 60% at 12 mo after DBS. In general, the MIoff (%) was positively correlated with preoperative SUVR in the temporo-parieto-occipital lobes, while it was inversely correlated with the metabolism in the primary motor cortex. The patients in the MIoff < 60% group showed a significant decrease in SUVR in the parieto-occipital lobes, while parieto-occipital metabolism in those with MIoff ≥ 60% was relatively preserved (Mann-Whitney U test, P = .03).

CONCLUSION

Our findings suggest that the parieto-occipital lobes may be implicated more generally in the prognosis of motor improvement after DBS in advanced PD than other regions.

Surgical Treatment of Parkinson's Disease: Devices and Lesion Approaches

Surgical treatments have transformed the management of Parkinson's disease (PD). Therapeutic options available for the management of PD motor complications include deep brain stimulation (DBS), ablative or lesioning procedures (pallidotomy, thalamotomy, subthalamotomy), and dopaminergic medication infusion devices. The decision to pursue these advanced treatment options is typically done by a multidisciplinary team by considering factors such as the patient's clinical characteristics, efficacy, ease of use, and risks of therapy with a goal to improve PD symptoms and quality of life. DBS has become the most widely used surgical therapy, although there is a re-emergence of interest in ablative procedures with the introduction of MR-guided focused ultrasound. In this article, we review DBS and lesioning procedures for PD, including indications, selection process, and management strategies.

Long-term Parkinson's disease quality of life after staged DBS: STN vs GPi and first vs second lead

Deep brain stimulation (DBS) for Parkinson's disease (PD) improves quality of life (QoL), but longitudinal follow-up data are scarce. We sought to quantify long-term benefits of subthalamic nucleus (STN) vs globus pallidus internus (GPi), and unilateral vs staged bilateral PD-DBS on postoperative QoL. This is a retrospective, longitudinal, non-randomized study using the PD QoL questionnaire (PDQ)-39 in patients with STN- or GPi-DBS, and with unilateral (N = 191) or staged bilateral (an additional contralateral lead implant) surgery (N = 127 and 156 for the first and second lead, respectively). Changes in PDQ-39 summary index (PDQ-39SI) and subscores throughout 60 months of follow-up were used as the primary analysis. We applied mixed models that included levodopa and covariates that differed at baseline across groups. For unilateral implantation, we observed an initial improvement in PDQ-39SI of 15.55 ± 3.29% (µ ± SE) across both brain targets at 4 months postoperatively. Unilateral STN patients demonstrated greater improvement in PDQ-39SI than GPi patients at 4 and 18 months postoperatively. Analysis of patients with staged bilateral leads revealed an initial 25.34 ± 2.74% (µ ± SE) improvement in PDQ-39SI at 4 months after the first lead with further improvement until 18 months, with no difference across targets. Scores did not improve after the second lead with gradual worsening starting at 18 months postoperatively. STN-DBS provided greater short-term QoL improvement than GPi-DBS for unilateral surgery. For staged bilateral DBS, overall QoL improvement was explained primarily by the first lead. Decision-making for patients considering DBS should include a discussion surrounding the potential risks and benefits from a second DBS lead.

Does post-operative symptomatic lead edema associated with subthalamic DBS implantation impact long-term clinical outcomes?

INTRODUCTION

Post-operative, non-hemorrhagic, non-infectious symptomatic delayed edema around the DBS lead is an uncommon complication of DBS surgery. We investigated whether this complication impacts clinical outcomes or has long-term sequelae.

METHODS

All Parkinson's disease (PD) patients with subthalamic nucleus (STN) DBS implantation who developed delayed symptomatic lead edema were identified. UPDRS part III motor, Parkinson's Disease Questionnaire (PDQ-39) total and MoCA scores were analyzed to assess motor outcome, quality of life and cognitive status at 1 year.

RESULTS

A total of 260 patients underwent 482 STN lead placements. Of these, 16 patients (20 leads, 4.1% of total 482 leads) developed this delayed complication. None of the patients had edema on immediate post-operative scan. Patients presented with varied symptoms including speech difficulty (n = 8), mild confusion (n = 6), headaches (n = 4), gait difficulty (n = 4) and seizures (n = 3). The mean duration for the diagnosis was 5.8 days after lead implantation and the mean duration for which follow-up CT scans reported complete/near complete resolution or improvement of edema was 4.7 weeks (range 2-10 weeks). At 1-year post-DBS, UPDRS motor scores improved significantly (42.5%, p < .001); quality of life improved, but the change was not statistically significant (21.3%, p = .197). There was no decline in cognitive function at 1 year (26.6 vs 26.4, p = .567). No long-term complication related to lead edema occurred in these patients.

CONCLUSION

Symptomatic lead edema after DBS surgery is an uncommon complication which typically resolves over time. In our series, there were no long-term sequelae of this complication and clinical outcomes were comparable to that reported in the literature.

An update on best practice of deep brain stimulation in Parkinson's disease

During the last 30 years, deep brain stimulation (DBS) has evolved into the clinical standard of care as a highly effective treatment for advanced Parkinson’s disease. Careful patient selection, an individualized anatomical target localization and meticulous evaluation of stimulation parameters for chronic DBS are crucial requirements to achieve optimal results. Current hardware-related advances allow for a more focused, individualized stimulation and hence may help to achieve optimal clinical results. However, current advances also increase the degrees of freedom for DBS programming and therefore challenge the skills of healthcare providers. This review gives an overview of the clinical effects of DBS, the criteria for patient, target, and device selection, and finally, offers strategies for a structured programming approach.

Comparison of Efficacy of Deep Brain Stimulation of Different Targets in Parkinson's Disease: A Network Meta-Analysis

Background: Deep brain stimulation (DBS) is considered an effective treatment option for Parkinson's disease (PD). Several studies have demonstrated the efficacy of neurostimulation in patients with advanced PD. The subthalamic nucleus (STN), the internal globus pallidus (GPi), ventral intermediate nucleus (Vim), and pedunculopontine nucleus (PPN) are reportedly effective DBS targets for control of Parkinsonian tremors. However, there is no consensus on the ideal target for DBS in patients with Parkinson's disease. Only a few studies have directly compared the efficacy of DBS of the Vim, STN, and GPi. Therefore, we searched PubMed, Embase, Cochrane Library, and other databases for observational studies, extracted data on unified Parkinson's disease rating scale (UPDRS) scores and performed a comprehensive network meta-analysis of different strategies of DBS and compared the efficiency of DBS at different targets. Methods: Forest plot was used to examine the overall efficiency of DBS; cumulative probability value was used to rank the strategies under examination. A node-splitting model was employed to assess consistency of reported outcomes inconsistency. A total of 16 studies which focused on UPDRS improvement were included in the network meta-analysis. Results: By comparing the overall efficiency associated with each target, we confirmed the efficacy of DBS therapy in PD. Our findings revealed similar efficacy of DBS targeted at GPi and STN in the on-medication phase [GPi-3.9 (95% CI -7.0 to -0.96); STN-3.1 (-5.9 to -0.38)]; however, in the off-medication phase, Vim-targeted DBS was associated with better improvement in UPDRS scores and could be a choice as a DBS target for tremor-dominant Parkinsonism. Conclusions: Our findings will help improve clinical application of DBS.

Relationship between perceived social support and patient-reported communication outcomes across communication disorders: a systematic review

BACKGROUND

Beyond the severity of voice, speech and language impairments, one potential predictor of communication success across adult populations with communication disorders may be perceived social support: the expectation that others will provide support if needed. Despite the preponderance of intervention approaches that assume a positive relationship between perceived social support and patient-reported communication success, the evidence base for these relationships is limited.

AIMS

The aim of this systematic review is to explore relationships between measures of perceived social support and patient-reported communication outcomes in adult populations with communication disorders.

METHODS & PROCEDURES

The PRISMA guidelines were followed in the conduct and reporting of this review. Electronic databases including PubMed, PsychINFO and CINAHL were systematically searched up to 19 May 2017. Additional data were obtained for two studies. All the included studies were appraised using the Critical Appraisal Skills Program (CASP) tools. Given the heterogeneous nature of the studies, data synthesis was narrative for the quantitative studies. A meta-ethnographic approach was used to synthesize qualitative data.

OUTCOMES & RESULTS

Eight quantitative and four qualitative studies met eligibility criteria. All quantitative studies met eight of eight quality criteria. For the qualitative studies, one study met nine of nine quality criteria; the remaining three studies met three, seven and eight quality criteria. Of the eight included quantitative studies, six independent data sets were used. Results revealed no significant relationships between perceived social support and communication outcomes in three studies (two aphasia with one data set, one Parkinson's disease), while perceived social support was a weak, but significant predictor in two studies (one multiple sclerosis, one head and neck cancer). Three additional studies (two aphasia with one data set; one Parkinson's disease) found that relationships were initially weak, but strengthened over time to become moderate. Results from qualitative studies (one head and neck cancer, two aphasia, one multiple sclerosis) revealed that perceived social support acted as a facilitator, and absent or misguided support acted as a barrier to communication outcomes. Skilful, responsive family members were able to facilitate better quality of communicative interactions, whereas lack of social support, or negative attitudes and behaviours of other people, were barriers.

CONCLUSIONS & IMPLICATIONS

While perceived social support may affect communication outcomes in adults with communication disorders, current measures may not adequately capture these constructs. Results have implications for future research and interventions for speech and language therapists.

The long-term efficacy of STN vs GPi deep brain stimulation for Parkinson disease: A meta-analysis

OBJECTIVE

This meta-analysis assessed the long-term efficacy of deep brain stimulation (DBS) of the subthalamic nucleus (STN) and globus pallidus interna (GPi) for Parkinson disease (PD).

METHODS

PubMed, Cochrane Library, and Clinical Trials databases were searched. Outcomes were unified Parkinson disease rating scale section (UPDRS) III off-medication score, Parkinson's disease questionnaire: 39 activities of daily living (PDQ-39 ADL) score, and levodopa-equivalent dosage after DBS.

RESULTS

During the off-medication state, pooled weighted mean difference (WMD) of UPDRS III score was .69 (95% confidence interval [CI] = -1.77 to 3.16, P = .58). In subgroup analysis, WMD of UPDRS III off-medication scores from baseline to 2 years and 3 years post-DBS were -.61 (95% CI = -2.97 to 1.75, P = .61) and 2.59 (95% CI = -2.30 to 7.47, P = .30). Pooled WMD of changes in tremor, rigidity, and gait scores were 1.12 (95% CI = -0.05 to 2.28, P = .06), 1.22 (95% CI = -0.51 to 2.94, P = .17) and .37 (95% CI = -0.13 to 0.87, P = .15), respectively. After DBS, pooled WMD of PDQ-39 ADL and LED were -3.36 (95% CI = -6.36 to -0.36, P = .03) and 194.89 (95% CI = 113.16 to 276.63, P < .001).

CONCLUSIONS

STN-DBS and GPi-DBS improve motor function and activities of daily living for PD. Differences in the long-term efficacy for PD on motor symptoms were not observed.

Some Clinically Useful Information that Neuropsychology Provides Patients, Carepartners, Neurologists, and Neurosurgeons About Deep Brain Stimulation for Parkinson's Disease

Deep brain stimulation (DBS) is an effective (but non-curative) treatment for some of the motor symptoms and treatment complications associated with dopaminergic agents in Parkinson's disease (PD). DBS can be done relatively safely and is associated with quality of life gains. In most DBS centers, neuropsychological evaluations are performed routinely before surgery, and sometimes after surgery. The purpose of such evaluation is not to decide solely on its results whether or not to offer DBS to a given candidate, but to provide the patient and treatment team with the best available information to make reasonable risk-benefit assessments. This review provides information relevant to the questions often asked by patients and their carepartners, neurologists, and neurosurgeons about neuropsychological outcomes of DBS, including neuropsychological adverse event rates, magnitude of cognitive changes, outcomes after unilateral versus bilateral surgery directed at various targets, impact of mild cognitive impairment (MCI) on outcome, factors implicated in neurobehavioral outcomes, and safety of newer interventions or techniques such as asleep surgery and current steering.

Deep brain stimulation for Parkinson’s disease: meta-analysis of results of randomized trials at varying lengths of follow-up

OBJECTIVE

Deep brain stimulation (DBS) is effective in the management of patients with advanced Parkinson’s disease (PD). While both the globus pallidus pars interna (GPi) and the subthalamic nucleus (STN) are accepted targets, their relative efficacy in randomized controlled trials (RCTs) has not been established beyond 12 months. The objective of this study was to conduct a meta-analysis of RCTs to compare outcomes among adults with PD undergoing DBS of GPi or STN at various time points, including 36 months of follow-up.

METHODS

The MEDLINE, Embase, CENTRAL, Web of Science, and CINAHL databases were searched. Registries for clinical trials, selected conference proceedings, and the table of contents for selected journals were also searched. Screens were conducted independently and in duplicate. Among the 623 studies initially identified (615 through database search, 7 through manual review of bibliographies, and 1 through a repeat screen of literature prior to submission), 19 underwent full-text review; 13 of these were included in the quantitative meta-analysis. Data were extracted independently and in duplicate. The Cochrane Collaboration tool was used to assess the risk of bias. The GRADE evidence profile tool was used to assess the quality of the evidence. Motor scores, medication dosage reduction, activities of daily living, depression, dyskinesias, and adverse events were compared. The influence of disease duration (a priori) and the proportion of male patients within a study (post hoc) were explored as potential subgroups.

RESULTS

Thirteen studies (6 original cohorts) were identified. No difference in motor scores or activities of daily living was identified at 36 months. Medications were significantly reduced with STN stimulation (5 studies, weighted mean difference [WMD] −365.46, 95% CI −599.48 to −131.44, p = 0.002). Beck Depression Inventory scores were significantly better with GPi stimulation (3 studies; WMD 2.53, 95% CI 0.99–4.06 p = 0.001). The motor benefits of GPi and STN DBS for PD are similar.

CONCLUSIONS

The motor benefits achieved with GPi and STN DBS for PD are similar. DBS of STN allows for a greater reduction of medication, but not as significant an advantage as DBS of GPi with respect to mood. This difference is sustained at 36 months. Further long-term studies are necessary.

Clinical outcomes following awake and asleep deep brain stimulation for Parkinson disease

OBJECTIVE

Recent studies have shown similar clinical outcomes between Parkinson disease (PD) patients treated with deep brain stimulation (DBS) under general anesthesia without microelectrode recording (MER), so-called “asleep” DBS, and historical cohorts undergoing “awake” DBS with MER guidance. However, few studies include internal controls. This study aims to compare clinical outcomes after globus pallidus internus (GPi) and subthalamic nucleus (STN) DBS using awake and asleep techniques at a single institution.

METHODS

PD patients undergoing awake or asleep bilateral GPi or STN DBS were prospectively monitored. The primary outcome measure was stimulation-induced change in motor function off medication 6 months postoperatively, measured using the Unified Parkinson’s Disease Rating Scale part III (UPDRS-III). Secondary outcomes included change in quality of life, measured by the 39-item Parkinson’s Disease Questionnaire (PDQ-39), change in levodopa equivalent daily dosage (LEDD), stereotactic accuracy, stimulation parameters, and adverse events.

RESULTS

Six-month outcome data were available for 133 patients treated over 45 months (78 GPi [16 awake, 62 asleep] and 55 STN [14 awake, 41 asleep]). UPDRS-III score improvement with stimulation did not differ between awake and asleep groups for GPi (awake, 20.8 points [38.5%]; asleep, 18.8 points [37.5%]; p = 0.45) or STN (awake, 21.6 points [40.3%]; asleep, 26.1 points [48.8%]; p = 0.20) targets. The percentage improvement in PDQ-39 and LEDD was similar for awake and asleep groups for both GPi (p = 0.80 and p = 0.54, respectively) and STN cohorts (p = 0.85 and p = 0.49, respectively).

CONCLUSIONS

In PD patients, bilateral GPi and STN DBS using the asleep method resulted in motor, quality-of-life, and medication reduction outcomes that were comparable to those of the awake method.

Subthalamic and Pallidal Deep Brain Stimulation for Parkinson's Disease

Deep brain stimulation (DBS) is a surgical treatment in which stimulation electrodes are permanently implanted in basal ganglia to treat motor fluctuations and symptoms of Parkinson's disease (PD). Subthalamic nucleus (STN) and globus pallidus internus (GPi) are the commonly used targets for DBS in PD. Many studies have compared motor and non-motor outcomes of DBS in both targets. However, the selection of PD patients for DBS targets is still poorly studied. Therefore, we performed this narrative review to summarize published studies comparing STN DBS and GPi DBS. GPi DBS is better for patients with problems in speech, mood, or cognition while STN DBS is better from an economic point of view as it allows much reduction in antiparkinson medications and less battery consumption.

Neuropsychological performance changes following subthalamic versus pallidal deep brain stimulation in Parkinson's disease: a systematic review and metaanalysis

BACKGROUND

Studies comparing subthalamus (STN) and globus pallidus internus (GPi) deep brain stimulation (DBS) for the management of Parkinson's disease in terms of neuropsychological performance are scarce and heterogeneous. Therefore, we performed a systematic review and metaanalysis to compare neuropsychological outcomes following STN DBS versus GPi DBS.

METHODS

A computer literature search of PubMed, the Web of Science, and Cochrane Central was conducted. Records were screened for eligible studies, and data were extracted and synthesized using Review Manager (v. 5.3 for Windows).

RESULTS

Seven studies were included in the qualitative synthesis. Of them, four randomized controlled trials (n=345 patients) were pooled in the metaanalysis models. The standardized mean difference (SMD) of change in the Stroop color-naming test favored the GPi DBS group (SMD=-0.31, p=0.009). However, other neuropsychological outcomes did not favor either of the two groups (Stroop word-reading: SMD=-0.21, p=0.08; the Wechsler Adult Intelligence Scale (WAIS) digits forward: SMD=0.08, p=0.47; Trail Making Test Part A: SMD=-0.05, p=0.65; WAIS-R digit symbol: SMD=-0.16, p=0.29; Trail Making Test Part B: SMD=-0.14, p=0.23; Stroop color-word interference: SMD=-0.16, p=0.18; phonemic verbal fluency: bilateral DBS SMD=-0.04, p=0.73, and unilateral DBS SMD=-0.05, p=0.83; semantic verbal fluency: bilateral DBS SMD=-0.09, p=0.37, and unilateral DBS SMD=-0.29, p=0.22; Boston Naming Test: SMD=-0.11, p=0.33; Beck Depression Inventory: bilateral DBS SMD=0.15, p=0.31, and unilateral DBS SMD=0.36, p=0.11).

CONCLUSIONS

There was no statistically significant difference in most of the neuropsychological outcomes. The present evidence does not favor any of the targets in terms of neuropsychological performance.

Subthalamic nucleus and globus pallidus internus stimulation for the treatment of Parkinson's disease: A systematic review

Objective

Deep brain stimulation (DBS) for treatment of advanced Parkinson’s disease (PD) has two anatomical targets: the subthalamic nucleus (STN) and the globus pallidus internus (GPI). The clinical effectiveness of these two stimulation targets was compared in the present study.

Methods

A systematic review and meta-analysis was performed to evaluated the postoperative changes in the United Parkinson’s Disease Rating Scale (UPDRS) on- and off-phase, on-stimulation motor scores; activities of daily living score (ADLS); and levodopa equivalent dose (LED) after STN and GPI stimulation. Randomized and nonrandomized controlled trials of PD treated by STN and GPI stimulation were considered for inclusion.

Results

Eight published reports of eligible studies involving 599 patients met the inclusion criteria. No significant differences were observed between the STN and GPI groups in the on-medication, on-stimulation UPDRS motor score [mean difference, 2.15; 95% confidence interval (CI), −0.96–5.27] or ADLS (mean difference, 3.40; 95% CI, 0.95–7.76). Significant differences in favor of STN stimulation were noted in the off-medication, on-stimulation UPDRS motor score (mean difference, 1.67; 95% CI, 0.98–2.37) and LED (mean difference, 130.24; 95% CI, 28.82–231.65).

Conclusion

The STN may be the preferred target for DBS in consideration of medication reduction, economic efficiency, and motor function improvement in the off phase. However, treatment decisions should be made according to the individual patient’s symptoms and expectations.

Comparison of Globus Pallidus Interna and Subthalamic Nucleus in Deep Brain Stimulation for Parkinson Disease: An Institutional Experience and Review

Deep Brain Stimulation (DBS) has revolutionized the lives of patients of Parkinson disease, offering therapeutic options to those not benefiting entirely from medications alone. With its proven track record of outperforming the best medical management, the goal is to unlock the full potential of this therapy. Currently, the Globus Pallidus Interna (GPi) and Subthalamic Nucleus (STN) are both viable targets for DBS, and the choice of site should focus on the constellation of symptoms, both motor and nonmotor, which are key determinants to quality of life. Our article sheds light on the specific advantages and drawbacks of the two sites, highlighting the need for matching the inherent properties of a target with specific desired effects in patients. UT Southwestern Medical Center has a robust and constantly evolving DBS program and the narrative from our center provides invaluable insight into the practical realities of DBS. The ultimate decision in selecting a DBS target is complex, ideally made by a multidisciplinary team, tailored towards each patient's profile and their expectations, by drawing upon scientific evidence coupled with experience. Ongoing research is expanding our knowledge base, which should be dynamically incorporated into an institute's DBS paradigm to ensure that patients receive the optimal therapy.

Seventy Years with the Globus Pallidus: Pallidal Surgery for Movement Disorders Between 1947 and 2017

The year 2017 marks the 70th anniversary of the birth of human stereotactic neurosurgery. The first procedure was a pallidotomy for Huntington's disease. However, it was for Parkinson's disease that pallidotomy was soon adopted worldwide. Pallidotomy was abandoned in the late 1950s in favor of thalamotomy because of the latter's more striking effect on tremor. The advent of levodopa put a halt to all surgery for PD. In the mid-1980s, Laitinen reintroduced the posteroventral pallidotomy of Leksell, and this procedure spread worldwide thanks to its efficacy on most parkinsonian symptoms including levodopa-induced dyskinesias and thanks to basic scientific work confirming the role of the globus pallidus internus in the pathophysiology of PD. With the advent of deep brain stimulation of the subthalamic nucleus, pallidotomy was again abandoned, and even DBS of the GPi has been overshadowed by STN DBS. The GPi reemerged in the late 1990s as a major stereotactic target for DBS in dystonia and, recently, in Tourette syndrome. Lately, lesioning of the GPI is being proposed to treat refractory status dystonicus or to treat DBS withdrawal syndrome in PD patients. Hence, the pallidum as a stereotactic target for either lesioning or DBS has been the phoenix of functional stereotactic neurosurgery, constantly abandoned and then rising again from its ashes. This review is a tribute to the pallidum on its 70th anniversary as a surgical target for movement disorders, analyzing its ebbs and flows and highlighting its merits, its versatility, and its resilience. © 2017 International Parkinson and Movement Disorder Society.

The effect of unilateral subthalamic nucleus deep brain stimulation on depression in Parkinson's disease

BACKGROUND

Depression is common in Parkinson's disease (PD) and adversely affects quality of life. Both unilateral and bilateral subthalamic (STN) deep brain stimulation (DBS) effectively treat the motor symptoms of PD, but questions remain regarding the impact of unilateral STN DBS on non-motor symptoms, such as depression.

METHODS

We report changes in depression, as measured by the Hamilton Depression Rating Scale (HAMD-17), in 50 consecutive PD patients who underwent unilateral STN DBS. Participants were also evaluated with UPDRS part III, Parkinson's Disease Questionnaire-39, and Pittsburgh Sleep Quality Index. The primary outcome was change in HAMD-17 at 6 months versus pre-operative baseline, using repeated measures analysis of variance (ANOVA). Secondary outcomes included the change in HAMD-17 at 3, 12, 18, and 24 months post-operatively and correlations amongst outcome variables using Pearson correlation coefficients. As a control, we also evaluated changes in HAMD-17 in 25 advanced PD patients who did not undergo DBS.

RESULTS

Participants with unilateral STN DBS experienced significant improvement in depression 6 months post-operatively (4.94 ± 4.02) compared to preoperative baseline (7.90 ± 4.44) (mean ± SD) (p = <0.0001). HAMD-17 scores did not correlate with UPDRS part III at any time-point. Interestingly, the HAMD-17 was significantly correlated with sleep quality and quality of life at baseline, 3 months, and 6 months post-operatively. Participants without DBS experienced no significant change in HAMD-17 over the same interval.

CONCLUSION

Unilateral STN DBS improves depression 6 months post-operatively in patients with PD. Improvement in depression is maintained over time and correlates with improvement in sleep quality and quality of life.

Orexin Directly Enhances the Excitability of Globus Pallidus Internus Neurons in Rat by Co-activating OX1 and OX2 Receptors

Orexin, released from the hypothalamus, has been implicated in various basic non-somatic functions including feeding, the sleep-wakefulness cycle, emotion, and cognition. However, the role of orexin in somatic motor control is still little known. Here, using whole-cell patch clamp recording and immunostaining, we investigated the effect and the underlying receptor mechanism of orexin-A on neurons in the globus pallidus internus (GPi), a critical structure in the basal ganglia and an effective target for deep brain stimulation therapy. Our results showed that orexin-A induced direct postsynaptic excitation of GPi neurons in a concentration-dependent manner. The orexin-A-induced excitation was mediated via co-activation of both OX1 and OX2 receptors. Furthermore, the immunostaining results showed that OX1 and OX2 receptors were co-localized in the same GPi neurons. These results suggest that the central orexinergic system actively modulates the motor functions of the basal ganglia via direct innervation on GPi neurons and presumably participates in somatic-non-somatic integration.

The human subthalamic nucleus and globus pallidus internus differentially encode reward during action control

The subthalamic nucleus (STN) and globus pallidus internus (GPi) have recently been shown to encode reward, but few studies have been performed in humans. We investigated STN and GPi encoding of reward and loss (i.e., valence) in humans with Parkinson's disease. To test the hypothesis that STN and GPi neurons would change their firing rate in response to reward- and loss-related stimuli, we recorded the activity of individual neurons while participants performed a behavioral task. In the task, action choices were associated with potential rewarding, punitive, or neutral outcomes. We found that STN and GPi neurons encode valence-related information during action control, but the proportion of valence-responsive neurons was greater in the STN compared to the GPi. In the STN, reward-related stimuli mobilized a greater proportion of neurons than loss-related stimuli. We also found surprising limbic overlap with the sensorimotor regions in both the STN and GPi, and this overlap was greater than has been previously reported. These findings may help to explain alterations in limbic function that have been observed following deep brain stimulation therapy of the STN and GPi. Hum Brain Mapp 38:1952-1964, 2017. © 2017 Wiley Periodicals, Inc.

Target Selection Recommendations Based on Impact of Deep Brain Stimulation Surgeries on Nonmotor Symptoms of Parkinson's Disease

OBJECTIVE

This review examines the evidence that deep brain stimulation (DBS) has extensive impact on nonmotor symptoms (NMSs) of patients with Parkinson's disease (PD).

DATA SOURCES

We retrieved information from the PubMed database up to September, 2015, using various search terms and their combinations including PD, NMSs, DBS, globus pallidus internus (GPi), subthalamic nucleus (STN), and ventral intermediate thalamic nucleus.

STUDY SELECTION

We included data from peer-reviewed journals on impacts of DBS on neuropsychological profiles, sensory function, autonomic symptoms, weight changes, and sleep disturbances. For psychological symptoms and cognitive impairment, we tried to use more reliable proofs: Random, control, multicenter, large sample sizes, and long period follow-up clinical studies. We categorized the NMSs into four groups: those that would improve definitively following DBS; those that are not significantly affected by DBS; those that remain controversial on their surgical benefit; and those that can be worsened by DBS.

RESULTS

In general, it seems to be an overall beneficial effect of DBS on NMSs, such as sensory, sleep, gastrointestinal, sweating, cardiovascular, odor, urological symptoms, and sexual dysfunction, GPi-DBS may produce similar results; Both STN and Gpi-DBS are safe with regard to cognition and psychology over long-term follow-up, though verbal fluency decline is related to DBS; The impact of DBS on behavioral addictions and dysphagia is still uncertain.

CONCLUSIONS

As the motor effects of STN-DBS and GPi-DBS are similar, NMSs may determine the target choice in surgery of future patients.

Effects of subthalamic deep brain stimulation with duloxetine on mechanical and thermal thresholds in 6OHDA lesioned rats

Chronic pain is the most common non-motor symptom of Parkinson's disease (PD) and is often overlooked. Unilateral 6-hydroxydopamine (6-OHDA) medial forebrain bundle lesioned rats used as models for PD exhibit decreased sensory thresholds in the left hindpaw. Subthalamic deep brain stimulation (STN DBS) increases mechanical thresholds and offers improvements with chronic pain in PD patients. However, individual responses to STN high frequency stimulation (HFS) in parkinsonian rats vary with 58% showing over 100% improvement, 25% showing 30-55% improvement, and 17% showing no improvement. Here we augment STN DBS by supplementing with a serotonin-norepinephrine reuptake inhibitor commonly prescribed for pain, duloxetine. Duloxetine was administered intraperitoneally (30mg/kg) in 15 parkinsonian rats unilaterally implanted with STN stimulating electrodes in the lesioned right hemisphere. Sensory thresholds were tested using von Frey, Randall-Selitto and hot-plate tests with or without duloxetine, and stimulation to the STN at HFS (150Hz), low frequency (LFS, 50Hz), or off stimulation. With HFS or LFS alone (left paw; p=0.016; p=0.024, respectively), animals exhibited a higher mechanical thresholds stable in the three days of testing, but not with duloxetine alone (left paw; p=0.183). Interestingly, the combination of duloxetine and HFS produced significantly higher mechanical thresholds than duloxetine alone (left paw, p=0.002), HFS alone (left paw, p=0.028), or baseline levels (left paw; p<0.001). These findings show that duloxetine paired with STN HFS increases mechanical thresholds in 6-OHDA-lesioned animals more than either treatment alone. It is possible that duloxetine augments STN DBS with a central and peripheral additive effect, though a synergistic mechanism has not been excluded.

Neuropsychological profile of Parkinson's disease patients selected for deep brain stimulation surgery

Background

Parkinson's disease (PD) shows symptoms involving motor and non-motor complications, including cognitive and behavioral changes, such changes might to contraindicate deep brain stimulation surgery (DBS).

Objective

The aim of study was to investigate the neuropsychological profile of patients with PD in a waiting list for DBS.

Methods

The neuropsychological evaluation was held in 30 patients of the ISCMPA Movement Disorders Clinic, with surgical indication based on the criteria of the responsible neurologists, in the period of 12 months. Instruments used: MMSE, FAB, MoCA, BDI, Semantic Verbal Fluency, PDQ-39, PDSS; and the UPDRS and Hoehn-Yahr scale.

Results

The patients were mostly male (66.7%) with a mean age of 59.37 (SD 10.60) and disease duration 9.33 (SD 4.08). There was cognitive impairment in 56.7% of patients by FAB and 76.7% by MoCA.

Conclusion

Even in the earliest stages of the disease, there is the incidence of non-motor symptoms, especially in those subjects who had an early onset of the disease.

Effects of high-frequency stimulation of the internal pallidal segment on neuronal activity in the thalamus in parkinsonian monkeys

Deep brain stimulation of the internal globus pallidus (GPi) is a major treatment for advanced Parkinson's disease. The effects of this intervention on electrical activity patterns in targets of GPi output, specifically in the thalamus, are poorly understood. The experiments described here examined these effects using electrophysiological recordings in two Rhesus monkeys rendered moderately parkinsonian through treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), after sampling control data in the same animals. Analysis of spontaneous spiking activity of neurons in the basal ganglia-receiving areas of the ventral thalamus showed that MPTP-induced parkinsonism is associated with a reduction of firing rates of segments of the data that contained neither bursts nor decelerations, and with increased burst firing. Spectral analyses revealed an increase of power in the 3- to 13-Hz band and a reduction in the γ-range in the spiking activity of these neurons. Electrical stimulation of the ventrolateral motor territory of GPi with macroelectrodes, mimicking deep brain stimulation in parkinsonian patients (bipolar electrodes, 0.5 mm intercontact distance, biphasic stimuli, 120 Hz, 100 μs/phase, 200 μA), had antiparkinsonian effects. The stimulation markedly reduced oscillations in thalamic firing in the 13- to 30-Hz range and uncoupled the spiking activity of recorded neurons from simultaneously recorded local field potential (LFP) activity. These results confirm that oscillatory and nonoscillatory characteristics of spontaneous activity in the basal ganglia receiving ventral thalamus are altered in MPTP-induced parkinsonism. Electrical stimulation of GPi did not entrain thalamic activity but changed oscillatory activity in the ventral thalamus and altered the relationship between spikes and simultaneously recorded LFPs.

Strategies to maintain quality of life among people with Parkinson's disease: what works?

Among chronic neurodegenerative disorders, Parkinson's disease (PD) is one of the most difficult and challenging to tackle as several motor and nonmotor features influence the patients' quality of life (QoL) and daily activities. Assessing patients QoL with valid instruments and gathering knowledge about the determinants that affect QoL in individuals with PD are the basis of an efficient caring strategy. In addition to the known motor symptoms, nonmotor disorders must also be comprehensively tracked and targeted for treatment to enhance QoL. A holistic strategy to maintain QoL in people with PD should consist of a multidisciplinary, personalized and patient-centered approach with timely administration of palliative care and efficient involvement of caregivers and family members.

Efficacies of globus pallidus stimulation and subthalamic nucleus stimulation for advanced Parkinson's disease: a meta-analysis of randomized controlled trials

OBJECTIVES

Deep brain stimulation (DBS) is the surgical procedure for patients with advanced Parkinson's disease. Globus pallidus internus (GPi) and subthalamic nucleus (STN) are the most targeted locations for the procedure. To investigate the variable efficiencies for the two different locations, we conducted a meta-analysis to compare both stimulation sites.

MATERIALS AND METHODS

A systematic search was performed in PubMed, Embase, and the Cochrane Library databases. Randomized controlled trials comparing the efficacies of GPi and STN DBS were included. Clinical outcomes of motor function, nonmotor function, and quality of life (QOL) were collected for the meta-analysis.

RESULTS

Ten eligible trials with 1,034 patients were included in the analysis. Unified Parkinson's disease rating scale III (UPDRS-III) scores were collected at 6, 12, and 24 months postsurgery separately to assess the motor function of the patients. A statistically significant effect in favor of the GPi DBS was obtained in the off-medication/on-stimulation phase of UPDRS-III at 12 months (mean difference [MD] =6.87, 95% confidence interval [95% CI]: 3.00-10.74, P=0.57, I (2)=0%). However, GPi DBS showed an opposite result at 24 months (MD =-2.46, 95% CI: -4.91 to -0.02, P=0.05, I (2)=0%). In the on-medication/on-stimulation phase, GPi DBS obtained a worse outcome compared with STN DBS (MD =-2.90, 95% CI: -5.71 to -0.09, P=0.05, I (2)=0%). Compared with STN DBS, increased dosage of levodopa equivalent doses was needed in GPi DBS (standardized MD =0.60, 95% CI: 0.46-0.74, P<0.00001, I (2)=24%). Meanwhile, Beck Depression Inventory II scores demonstrated that STN has a better performance (standardized MD =-0.31, 95% CI: -0.51 to -0.12, P=0.002, I (2)=0%). As for neurocognitive phase postsurgery, GPi DBS showed better performance in three of the nine tests, especially in verbal fluency. Use of GPi DBS was associated with a greater effect in eight of the nine subscales of QOL.

CONCLUSION

GPi and STN DBS significantly improve advanced Parkinson's patients' symptoms, functionality, and QOL. Variable therapeutic efficiencies were observed in both procedures, GPi and STN DBS. GPi DBS allowed greater recovery of verbal fluency and provided greater relief of depression symptoms. Better QOL was also obtained using GPi DBS. Meanwhile, GPi DBS was also associated with increased dosage of levodopa equivalent doses. The question regarding which target is superior remained open for discussion. An understanding of the target selection still depends on individual symptoms, neurocognitive/mood status, therapeutic goals of DBS (eg, levodopa reduction), and surgical expertise.

Update on Deep Brain Stimulation for Dyskinesia and Dystonia: A Literature Review

Deep brain stimulation (DBS) has been an established surgical treatment option for dyskinesia from Parkinson disease and for dystonia. The present article deals with the timing of surgical intervention, selecting an appropriate target, and minimizing adverse effects. We provide an overview of current evidences and issues for dyskinesia and dystonia as well as emerging DBS technology.

Effects of neurostimulation for advanced Parkinson's disease patients on motor symptoms: A multiple-treatments meta-analysas of randomized controlled trials

Deep brain stimulation (DBS) is the surgical procedure of choice for patients with advanced Parkinson disease (PD). We aim to evaluate the efficacy of GPi (globus pallidus internus), STN (subthalamic nucleus)-DBS and medical therapy for PD. We conducted a systematic review and multiple-treatments meta-analysis to investigate the efficacy of neurostimulation and medical therapy for PD patients. Sixteen eligible studies were included in this analysis. We pooled the whole data and found obvious difference between GPi-DBS versus medical therapy and STN-DBS versus medical therapy in terms of UPDRS scores (Unified Parkinson’s Disease Rating Scale). Meanwhile, we found GPi-DBS had the similar efficacy on the UPDRS scores when compared with STN-DBS. What is more, quality of life, measured by PDQ-39 (Parkinson’s disease Questionnaire) showed greater improvement after GPi-DBS than STN-DBS. Five studies showed STN-DBS was more effective for reduction in medication than GPi-DBS. Overall, either GPi-DBS or STN-DBS was an effective technique to control PD patients’ symptoms and improved their functionality and quality of life. Meanwhile, the UPDRS scores measuring parkinsonian symptoms revealed no significant difference between GPi-DBS and STN-DBS. STN-DBS was more effective for reduction in medication than GPi-DBS. Alternatively, GPi-DBS was more effective for improving the PDQ-39 score than STN-DBS.

Stimulation-Induced Transient Nonmotor Psychiatric Symptoms following Subthalamic Deep Brain Stimulation in Patients with Parkinson's Disease: Association with Clinical Outcomes and Neuroanatomical Correlates

BACKGROUND

The clinical and neurobiological underpinnings of transient nonmotor (TNM) psychiatric symptoms during the optimization of stimulation parameters in the course of subthalamic nucleus deep brain stimulation (STN-DBS) remain under intense investigation.

METHODS

Forty-nine patients with refractory Parkinson's disease underwent bilateral STN-DBS implants and were enrolled in a 24-week prospective, naturalistic follow-up study. Patients who exhibited TNM psychiatric manifestations during DBS parameter optimization were evaluated for potential associations with clinical outcome measures.

RESULTS

Twenty-nine TNM+ episodes were reported by 15 patients. No differences between TNM+ and TNM- groups were found in motor outcome. However, unlike the TNM- group, TNM+ patients did not report improvement in subsyndromal depression or quality of life. TNM+ episodes were more likely to emerge during bilateral monopolar stimulation of the medial STN.

CONCLUSIONS

The occurrence of TNM psychiatric symptoms during optimization of stimulation parameters was associated with the persistence of subsyndromal depression and with lower quality of life ratings at 6 months. The neurobiological underpinnings of TNM symptoms are investigated yet remain difficult to explain.

Deep Brain Stimulation for Movement Disorders of Basal Ganglia Origin: Restoring Function or Functionality?

Deep brain stimulation (DBS) is highly effective for both hypo- and hyperkinetic movement disorders of basal ganglia origin. The clinical use of DBS is, in part, empiric, based on the experience with prior surgical ablative therapies for these disorders, and, in part, driven by scientific discoveries made decades ago. In this review, we consider anatomical and functional concepts of the basal ganglia relevant to our understanding of DBS mechanisms, as well as our current understanding of the pathophysiology of two of the most commonly DBS-treated conditions, Parkinson's disease and dystonia. Finally, we discuss the proposed mechanism(s) of action of DBS in restoring function in patients with movement disorders. The signs and symptoms of the various disorders appear to result from signature disordered activity in the basal ganglia output, which disrupts the activity in thalamocortical and brainstem networks. The available evidence suggests that the effects of DBS are strongly dependent on targeting sensorimotor portions of specific nodes of the basal ganglia-thalamocortical motor circuit, that is, the subthalamic nucleus and the internal segment of the globus pallidus. There is little evidence to suggest that DBS in patients with movement disorders restores normal basal ganglia functions (e.g., their role in movement or reinforcement learning). Instead, it appears that high-frequency DBS replaces the abnormal basal ganglia output with a more tolerable pattern, which helps to restore the functionality of downstream networks.

Long-term impact on quality of life of subthalamic nucleus stimulation in Parkinson's disease

Long-term impact of bilateral subthalamic nucleus deep brain stimulation (STN-DBS) on health-related quality of life (HRQOL) and associated factors in patients with Parkinson's disease (PD) are not clear. In this prospective study, we included 69 PD patients (64 % men, mean age 61.3 ± 7.4 and disease duration 13.2 ± 5.7 years) undergoing STN-DBS. They were evaluated preoperatively (baseline), 1 and 5 years postoperatively assessing 39-item Parkinson's Disease Questionnaire (PDQ-39), Schwab and England Activities of Daily Living Scale (SEADL), Unified Parkinson's Disease Rating Scale (UPDRS) off- and on-medication, patient diaries, dopaminergic treatment, mortality and surgical complications. Five years postoperatively, off-medication, there were improvements from baseline in UPDRS-II and III total (27.2 and 26.7 %, respectively) and SEADL (18.6 % more completely independent patients) (p < 0.05) scores, while on-medication, there was a deterioration in UPDRS-III (37.8 %, mainly axial signs) (p < 0.05) and minor improvements in SEADL (3.7 %). While at 1 year PDQ-39, the summary index improved substantially (36.5 %) (p < 0.05), at 5 years patients regressed (only 8.8 %) (p < 0.05), though changes in PDQ-39 subscores remained significant, with improvements in ADL (18.8 %), emotional well-being (19.0 %), stigma (36.4 %) and discomfort (20.6 %), despite worsening in communication (47.8 %) (p < 0.05). Lower preoperative PDQ-39 summary index and greater 1-year UPDRS-III-off total score gain predicted better long-term HRQOL. STN-DBS produces long-term improvements in HRQOL in PD. Preoperative HRQOL and short-term postoperative changes in off-medication motor status may predict long-term HRQOL in PD following STN-DBS.

Deep brain stimulation of pallidal versus subthalamic for patients with Parkinson's disease: a meta-analysis of controlled clinical trials

BACKGROUND

Parkinson's disease (PD) is a common neurodegenerative disorder that affects many people every year. Deep brain stimulation (DBS) is an effective nonpharmacological method to treat PD motor symptoms. This meta-analysis was conducted to evaluate the efficacy of subthalamic nucleus (STN)-DBS versus globus pallidus internus (GPi)-DBS in treating advanced PD.

METHODS

Controlled clinical trials that compared STN-DBS to GPi-DBS for short-term treatment of PD in adults were researched up to November 2015. The primary outcomes were the Unified Parkinson's Disease Rating Scale Section (UPDRS) III score and the levodopa-equivalent dosage (LED) after DBS. The secondary outcomes were the UPDRS II score and the Beck Depression Inventory (BDI) score.

RESULTS

Totally, 13 studies containing 1,148 PD patients were included in this meta-analysis to compare STN-DBS versus GPi-DBS. During the off-medication state, the pooled weighted mean difference (WMD) of UPDRS III and II scores were -2.18 (95% CI =-5.11 to 0.74) and -1.96 (95% CI =-3.84 to -0.08), respectively. During the on-medication state, the pooled WMD of UPDRS III and II scores were 0.15 (95% CI =-1.14 to 1.44) and 1.01 (95% CI =0.12 to 1.89), respectively. After DBS, the pooled WMD of LED and BDI were -254.48 (95% CI =-341.66) and 2.29 (95% CI =0.83 to 3.75), respectively.

CONCLUSION

These results indicate that during the off-medication state, the STN-DBS might be superior to GPi-DBS in improving the motor function and activities of daily living for PD patients; but during the on-medication state, the opposite result is observed. Meanwhile, the STN-DBS is superior at reducing the LED, whereas the GPi-DBS shows a significantly greater reduction in BDI score after DBS.

Cognitive and Psychiatric Effects of STN versus GPi Deep Brain Stimulation in Parkinson's Disease: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Deep brain stimulation (DBS) of either the subthalamic nucleus (STN) or the globus pallidus interna (GPi) can reduce motor symptoms in patients with Parkinson's disease (PD) and improve their quality of life. However, the effects of STN DBS and GPi DBS on cognitive functions and their psychiatric effects remain controversial. The present meta-analysis was therefore performed to clarify these issues.

METHODS

We searched the PUBMED, EMBASE, and the Cochrane Central Register of Controlled Trials databases. Other sources, including internet-based clinical trial registries and grey literature sources, were also searched. After searching the literature, two investigators independently performed literature screens to assess the quality of the included trials and to extract the data. The outcomes included the effects of STN DBS and GPi DBS on multiple cognitive domains, depression, anxiety, and quality of life.

RESULTS

Seven articles related to four randomized controlled trials that included 521 participants were incorporated into the present meta-analysis. Compared with GPi DBS, STN DBS was associated with declines in selected cognitive domains after surgery, including attention, working memory and processing speed, phonemic fluency, learning and memory, and global cognition. However, there were no significant differences in terms of quality of life or psychiatric effects, such as depression and anxiety, between the two groups.

CONCLUSIONS

A selective decline in frontal-subcortical cognitive functions is observed after STN DBS in comparison with GPi DBS, which should not be ignored in the target selection for DBS treatment in PD patients. In addition, compared to GPi DBS, STN DBS does not affect depression, anxiety, and quality of life.