Repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex to alleviate depression and cognitive impairment associated with Parkinson's disease: A review and clinical implications

Assessment of noninvasive brain stimulation interventions in Parkinson's disease: a systematic review and network meta-analysis

A network meta-analysis of randomized controlled trials was conducted to compare and rank the effectiveness of various noninvasive brain stimulation (NIBS) for Parkinson's disease (PD). We searched PubMed, Web of Science, Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), Wanfang Database, China Science and Technology Journal Database (VIP), and Chinese Biomedical Literature Service System (SinoMed) databases from the date of database inception to April 30th, 2024. Two researchers independently screened studies of NIBS treatment in patients with PD based on inclusion and exclusion criteria. Two researchers independently performed data extraction of the included studies using an Excel spreadsheet and assessed the quality of the literature according to the Cochrane Risk of Bias Assessment Tool (RoB2). Network meta-analysis was performed in StataMP 17.0. A total of 28 studies involving 1628 PD patients were included. The results showed that HF-rTMS over the SMA (SMD = - 2.01; 95% CI [- 2.87, - 1.15]), HF-rTMS over the M1 and DLPFC (SMD = - 1.80; 95% CI [- 2.90, - 0.70]), HF-rTMS over the M1 (SMD = - 1.10; 95% CI [- 1.55, - 0.65]), a-tDCS over the DLPFC (SMD = - 1.08; 95% CI [- 1.90, - 0.27]), HF-rTMS over the M1 and PFC (SMD = - 0.92; 95% CI [- 1.71, - 0.14]), LF-rTMS over the M1 (SMD = - 0.72; 95% CI [- 1.17, - 0.28]), and HF-rTMS over the DLPFC (SMD = - 0.70; 95% CI [- 1.21, - 0.19]) were significantly improved motor function compared with sham stimulation. The SUCRA three highest ranked were HF-rTMS over the SMA (95.1%), HF-rTMS over the M1 and DLPFC (89.6%), and HF-rTMS over the M1 (73.0%). In terms of enhanced cognitive function, HF-rTMS over the DLPFC (SMD = 0.80; 95% CI [0.03,1.56]) was significantly better than sham stimulation. The SUCRA three most highly ranked were a-tDCS over the M1 (69.8%), c-tDCS over the DLPFC (66.9%), and iTBS over the DLPFC (65.3%). HF-rTMS over the M1 (SMD = - 1.43; 95% CI [- 2.26, - 0.61]) and HF-rTMS over the DLPFC (SMD = - 0.79; 95% CI [- 1.45, - 0.12)]) significantly improved depression. The SUCRA three highest ranked were HF-rTMS over the M1 (94.1%), LF-rTMS over the M1 (71.8%), and HF-rTMS over the DLPFC (69.0%). HF-rTMS over the SMA may be the best option for improving motor symptoms in PD patients. a-tDCS and HF-rTMS over the M1 may be the NIBS with the most significant effects on cognition and depression, separately.Trial registration: International Prospective Register of Systematic Review, PROSPERO (CRD42023456088).

Predicting the occurrence of mild cognitive impairment in Parkinson's disease using structural MRI data

Introduction

Mild cognitive impairment (MCI) is a common symptom observed in individuals with Parkinson's disease (PD) and a main risk factor for progressing to dementia. Our objective was to identify early anatomical brain changes that precede the transition from healthy cognition to MCI in PD.

Methods

Structural T1-weighted magnetic resonance imaging data of PD patients with healthy cognition at baseline were downloaded from the Parkinson's Progression Markers Initiative database. Patients were divided into two groups based on the annual cognitive assessments over a 5-year time span: (i) PD patients with unstable healthy cognition who developed MCI over a 5-year follow-up (PD-UHC, n = 52), and (ii) PD patients who maintained stable healthy cognitive function over the same period (PD-SHC, n = 52). These 52 PD-SHC were selected among 192 PD-SHC patients using propensity score matching method to have similar demographic and clinical characteristics with PD-UHC at baseline. Seventy-five percent of these were used to train a support vector machine (SVM) algorithm to distinguish between the PD-UHC and PD-SHC groups, and tested on the remaining 25% of individuals. Shapley Additive Explanations (SHAP) feature analysis was utilized to identify the most informative brain regions in SVM classifier.

Results

The average accuracy of classifying PD-UHC vs. PD-SHC was 80.76%, with 82.05% sensitivity and 79.48% specificity using 10-fold cross-validation. The performance was similar in the hold-out test sets with all accuracy, sensitivity, and specificity at 76.92%. SHAP analysis showed that the most influential brain regions in the prediction model were located in the frontal, occipital, and cerebellar regions as well as midbrain.

Discussion

Our machine learning-based analysis yielded promising results in identifying PD individuals who are at risk of cognitive decline from the earliest disease stage and revealed the brain regions which may be linked to the prospective cognitive decline in PD before clinical symptoms emerge.

Non-invasive brain stimulation for patients and healthy subjects: Current challenges and future perspectives

Non-invasive brain stimulation (NIBS) techniques have a rich historical background, yet their utilization has witnessed significant growth only recently. These techniques encompass transcranial electrical stimulation and transcranial magnetic stimulation, which were initially employed in neuroscience to explore the intricate relationship between the brain and behaviour. However, they are increasingly finding application in research contexts as a means to address various neurological, psychiatric, and neurodegenerative disorders. This article aims to fulfill two primary objectives. Firstly, it seeks to showcase the current state of the art in the clinical application of NIBS, highlighting how it can improve and complement existing treatments. Secondly, it provides a comprehensive overview of the utilization of NIBS in augmenting the brain function of healthy individuals, thereby enhancing their performance. Furthermore, the article delves into the points of convergence and divergence between these two techniques. It also addresses the existing challenges and future prospects associated with NIBS from ethical and research standpoints.

Memory Deficits in Parkinson's Disease Are Associated with Impaired Attentional Filtering and Memory Consolidation Processes

The present study examined mechanisms underlying memory deficits in Parkinson's disease (PD) and their associations with brain structural metrics. Nineteen PD patients and twenty-two matched controls underwent two memory experiments. In Experiment 1 (delayed memory task), subjects were asked to remember an array of colored rectangles with varying memory set sizes (Low-Load (2 items), Low-Load (relevant 2 items) with Distractor (irrelevant 3 items), and High-Load (5 items)). After a 7 s delay period, they reported whether the orientation of any relevant figures had changed (test period). In Experiment 2 (working memory task), memory arrays were presented in varying set sizes (2 to 6 items) without distractors, followed by a 2 s delay period and a subsequent test period. Brain MRI data were acquired to assess structural differences (volumes and cortical thickness) in areas related to attention, working memory storage capacity, and episodic memory. Multivariate analyses of covariance revealed that, compared with controls, PD patients had lower memory capacity scores in all memory load conditions for Experiment 1 (p < 0.021), whereas there were no group differences in any memory load conditions for Experiment 2 (p > 0.06). In addition, PD patients had lower cortical thickness in the left superior temporal gyrus (p = 0.02), a region related to the ventral attentional system. Moreover, regression analyses revealed that lower cortical thickness values in the left superior temporal gyrus significantly predicted lower memory scores of Low-Load and Low-Load with Distractor conditions in Experiment 1 (p < 0.044) and lower scores of memory load conditions of 4 and 5 items in Experiment 2 (p < 0.012). These findings suggest that memory deficits in PD may partly be due to impaired attentional filtering and memory consolidation processes that may be related to superior temporal neurodegeneration. Future studies are warranted to confirm the current findings to guide the development of effective treatments for memory deficits in PD.

Therapeutic effects of repetitive transcranial magnetic stimulation on cognitive impairment in stroke patients: a systematic review and meta-analysis

Background

In recent years, repetitive transcranial magnetic stimulation (rTMS) has emerged as a noninvasive and painless treatment for post-stroke cognitive impairment (PSCI). However, few studies have analyzed the intervention parameters of cognitive function and the effectiveness and safety of rTMS for treating patients with PSCI. Thus, this meta-analysis aimed to analyze the interventional parameters of rTMS and evaluate the safety and effectiveness of rTMS for treating patients with PSCI.

Methods

According to the PRISMA guidelines, we searched the Web of Science, PubMed, EBSCO, Cochrane Library, PEDro, and Embase to retrieve randomized controlled trials (RCTs) of rTMS for the treatment of patients with PSCI. Studies were screened according to the inclusion and exclusion criteria, and two reviewers independently performed literature screening, data extraction, and quality assessment. RevMan 5.40 software was used for data analysis.

Results

12 RCTs involving 497 patients with PSCI met the inclusion criteria. In our analysis, rTMS had a positive therapeutic effect on cognitive rehabilitation in patients with PSCI (P < 0.05). Both high-frequency rTMS and low-frequency rTMS were effective in improving the cognitive function of patients with PSCI by stimulating the dorsolateral prefrontal cortex (DLPFC), but their efficacy was not statistically different (P > 0.05).

Conclusions

rTMS treatment on the DLPFC can improve cognitive function in patients with PSCI. There is no significant difference in the treatment effect of high-frequency rTMS and low-frequency rTMS in patients with PSCI between high-frequency and low-frequency rTMS.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=323720, identifier CRD 42022323720.

Efficacy of non-pharmacological interventions on depressive symptoms in patients with Parkinson's disease: a study protocol for a systematic review and network meta-analysis

INTRODUCTION

Depression is the most dominant non-motor symptom of Parkinson's disease (PD), with a prevalence of up to 50%, and can lead to a range of psychiatric and psychological problems that can affect quality of life and overall functioning. While several randomised controlled trials (RCTs) have tested the effect of certain non-pharmacological interventions on the outcome of PD depression symptoms, the comparative benefits and harms of these remain unclear. We will conduct a systematic review and network meta-analysis to compare the efficacy and safety of different non-pharmacological interventions for patients with PD depression.

METHODS AND ANALYSIS

We will search PubMed, Web of Science, Cochrane, Embase, Google Scholar, the Chinese National Knowledge Infrastructure, the Chinese Biomedical Literature Database, WanFang Data and the Chongqing VIP Database from their inception date to June 2022. The studies will be limited to results published in English or Chinese. The primary outcomes will be the changes in the depressive symptoms, while secondary outcomes will include adverse effects and the quality of life. Two researchers will screen those documents that meet the inclusion criteria, extracting data according to the preset table and evaluating the methodological quality of the included studies using the Cochrane Risk of Bias 2.0 Tool. The STATA and ADDIS statistical software will be used to conduct a systematic review and network meta-analysis. A traditional pairwise meta-analysis and a network meta-analysis will be performed to compare the efficacy and safety of different non-pharmacological interventions, ensuring the robustness of the findings. The Grading of Recommendations Assessment, Development and Evaluation system will be used to assess the overall quality of the body of evidence associated with the main results. The publication bias assessment will be conducted using comparison-adjusted funnel plots.

ETHICS AND DISSEMINATION

All the data for this study will be extracted from published RCTs. As a literature-based systematic review, this study does not require ethical approval. The results will be disseminated through peer-reviewed journals and national/international conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42022347772.

Synergistic Associations of Depressive Symptoms and Aging on Cognitive Decline in Early Parkinson’s Disease

Objective

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder. About 40%-50% of PD patients experience depression, making it one of the most common neuropsychiatric disturbances in PD. Cognitive deficits (e.g., difficulties with memory, attention) are an additional common complication in PD. Past studies among healthy aging individuals suggest that depression is a risk factor for cognitive decline, and the risk increases with older age. This study aims to examine the association between depressive symptoms on cognitive decline as a function of age among patients with PD. It is hypothesized that older PD patients with more severe depressive symptoms will be at greater risk of cognitive decline than their younger or less depressed counterparts.

Methods

Four hundred and eighty-seven newly diagnosed patients with PD, were assessed for depression and cognition over a five-year period. Participants completed neuropsychological tests that assessed memory, learning, attention, visuospatial functioning, processing speed, and verbal fluency. Multilevel-modeling was used to examine the longitudinal association between cognition, age, and depressive symptoms.

Results

Our results indicated a significant three-way interaction (age X occasion X depressive symptoms) predicting language and working memory/attention performance. More specifically, detrimental associations of depressive symptoms on cognitive decline in these domains were more pronounced among older adults.

Conclusions

Our findings support that older PD patients with comorbid depressive symptoms experience greater cognitive decline compared to their younger counterparts. Findings suggest that older individuals with PD may be more vulnerable to neurotoxic effects of depression (e.g., neuroinflammation, HPA axis disruption), and better management of depression could potentially reduce cognitive decline and dementia risk.

Acute improvement in the attention network with repetitive transcranial magnetic stimulation in Parkinson's disease

PURPOSE

To investigate the effect of two weeks of repetitive transcranial magnetic stimulation (rTMS) on the attention network in Parkinson's disease (PD) patients.

MATERIALS AND METHODS

Sixty PD patients were randomly divided into equal-sized active- and sham-rTMS groups. Executive function was assessed by neuropsychological tests including the Trail-Making Test (TMT), word fluency test, digit span, Wisconsin Card Sorting Test (WCST) and Stroop test. The attention network was evaluated by the attention network test (ANT). rTMS (5 Hz) was applied over the left dorsolateral prefrontal cortex (DLPFC) in the active-rTMS group, and the sham-rTMS group underwent sham stimulation, both for two weeks. All tests were performed before and after rTMS.

RESULTS

After active rTMS, nonparametric analysis revealed significant improvements in categories completed (CC) (p < 0.001) in the WCST and reaction times (RTs) in part 3 (p = 0.002) and the Stroop interference effect (SIE) (p < 0.001) in the Stroop test. Regarding the ANT, the RTs of the executive control network were significantly reduced (p < 0.001). There was no significant change after sham rTMS.

CONCLUSIONS

In the short term, in PD patients, rTMS improved the executive control network involved in resolving conflicting information. However, it showed milder effects on neuropsychological test outcomes assessing executive function, which may involve different neuromechanisms.Implications for rehabilitationCognitive impairment is common in patients with Parkinson's disease (PD), and it is related to functional disability and reduced quality of life.Attention is a main component of the cognitive system, and attention deficits are responsible for disability.This study demonstrates that rTMS is beneficial for cognitive rehabilitation in PD, as patients showed improved performance on the attention network test and neuropsychological tests.

Efficacy of repetitive transcranial magnetic stimulation in Parkinson's disease: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive form of brain stimulation that positively regulates the motor and non-motor symptoms of Parkinson's disease (PD). Although, most reviews and meta-analysis have shown that rTMS intervention is effective in treating motor symptoms and depression, very few have used randomised controlled trials (RCTs) to analyse the efficacy of this intervention in PD. We aimed to review RCTs of rTMS in patients with PD to assess the efficacy of rTMS on motor and non-motor function in patients with PD.

METHODS

In this systematic review and meta-analysis, we searched PubMed, MEDLINE and Web of Science databases for RCTs on rTMS in PD published between January 1, 1988 to January 1, 2022. Eligible studies included sham-controlled RCTs that used rTMS stimulation for motor or non-motor symptoms in PD. RCTs not focusing on the efficacy of rTMS in PD were excluded. Summary data were extracting from those RCTs by two investigators independently. We then calculated standardised mean difference with random-effect models. The main outcome included motor and non-motor examination of scales that were used in PD motor or non-motor assessment. This study was registered with PROSPERO, CRD42022329633.

FINDINGS

Fourteen studies with 469 patients met the criteria for our meta-analysis. Twelve eligible studies with 381 patients were pooled to analyse the efficacy of rTMS on motor function improvement. The effect size on motor scale scores was 0.51 (P < 0.0001) and were not distinctly heterogeneous (I² = 29%). Five eligible studies with 202 patients were collected to evaluate antidepressant-like effects. The effect size on depression scale scores was 0.42 (P = 0.004), and were not distinctly heterogeneous (I² = 25%), indicating a significant anti-depressive effect (P = 0.004). The results suggest that high-frequency of rTMS on primary motor cortex (M1) is effective in improving motor symptoms; while the dorsolateral prefrontal cortex (DLPFC) may be a potentially effective area in alleviating depressive symptom.

INTERPRETATION

The findings suggest that rTMS could be used as a possible adjuvant therapy for PD mainly to improve motor symptoms, but could have potential efficacy on depressive symptoms of PD. However, further investigation is needed.

FUNDING

The National Natural Science Foundation of China (NO: 81873777, 82071414), Initiated Foundation of Zhujiang Hospital (NO: 02020318005), Scientific Research Foundation of Guangzhou (NO: 202206010005), and Science and Technology Program of Guangdong of China (NO: 2020A0505100037).

Effects of repeated transcranial magnetic stimulation in the dorsolateral prefrontal cortex versus motor cortex in patients with neuropathic pain after spinal cord injury: a study protocol

INTRODUCTION

Neuropathic pain is one of the common complications of spinal cord injuries (SCI), which will slow down the recovery process and result in lower quality of life. Previous studies have shown that repeated transcranial magnetic stimulation (rTMS) of the motor cortex (M1) can reduce the average pain and the most severe pain of neuropathic pain after SCI. The dorsolateral prefrontal cortex (DLPFC) area is a common target of rTMS. Recently, a few studies found that rTMS of DLPFC may relieve the neuropathic pain of SCI. Compared with the M1 area, the efficacy of rTMS treatment in the DLPFC area in improving neuropathic pain and pain-related symptoms in patients with SCI is still unclear. Therefore, our study aims to evaluate the non-inferiority of rTMS in the DLPFC vs M1 in patients with neuropathic pain after SCI, in order to provide more options for rTMS in treating neuropathic pain after SCI.

METHODS AND ANALYSIS

We will recruit 50 subjects with neuropathic pain after SCI. They will be randomly assigned to the DLPFC- rTMS and M1-rTMS groups and be treated with rTMS for 4 weeks. Except for the different stimulation sites, the rTMS treatment programmes of the two groups are the same: 10 Hz, 1250 pulses, 115% intensity threshold, once a day, five times a week for 4 weeks. VAS, simplified McGill Pain Questionnaire, Spinal Cord Injury Pain Date Set, Pittsburgh Sleep Quality Index and Hamilton Anxiety Scale will be evaluated at baseline, second week of treatment, fourth week of treatment and 4 weeks after the end of treatment. And VAS change will be calculated.

ETHICS AND DISSEMINATION

The Ethics Committee of the Affiliated Hospital of Southwest Medical University has approved this trial, which is numbered KY2020041. Written informed consent will be provided to all participants after verification of the eligibility criteria. The results of the study will be published in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ChiCTR2000032362.

Cognitive dysfunction and neuropsychiatric aspects of Parkinson's disease

Movement abnormalities, by definition, and cognitive changes, to varying extents, affect every patient with Parkinson's disease (PD) and are attributed to the underlying neurodegenerative disease. Various psychiatric disorders occur in most patients at some point over the course of PD, including in the prodromal phase. Even though psychiatric disturbances tend to aggravate motor and cognitive deficits, they are under-recognized and under-treated, and the role of the underlying neurological disease is often minimized. To provide an integrated approach to understanding neuropsychiatric aspects of PD, this chapter reviews how cognitive changes in PD relate to the common psychiatric disturbances in PD along with the prevalence, phenomenology, pathophysiology, and treatment of each.

High-Frequency Repetitive Transcranial Magnetic Stimulation Over the Left Dorsolateral Prefrontal Cortex Shortly Alleviates Fatigue in Patients With Multiple System Atrophy: A Randomized Controlled Trial

Background: Fatigue is a common symptom in patients with Multiple system atrophy (MSA), but effective treatments remain elusive. The present study aims to investigate whether high-frequency repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (DLPFC) could relieve fatigue in patients with MSA.

Methods: This is a single-center, randomized and double-blind trial. Twenty-two patients with MSA and fatigue were randomly allocated to receive 10 sessions of either active (N = 11) or sham (N = 11) 10 Hz rTMS over the left DLPFC. The participants were assessed at baseline (T0), after the last session of treatment (T1), and at 2-week (T2), and 4-week (T3) follow-up timepoints. The primary outcomes were Fatigue Severity Scale-9 (FSS-9) scores, with Unified Multiple System Atrophy Rating Scale (UMSARS), 17-item Hamilton Depression Scale (HAMD-17), and Hamilton Anxiety Scale (HAMA) as secondary outcomes.

Results: Two-way repeated ANOVAs revealed significant group × time interactions for FSS-9 scores (p < 0.001), HAMD-17 scores (p = 0.01), HAMA scores (p = 0.01), and UMRSA part II (p = 0.05). Post-hoc analyses showed that compared to T0, the active group exhibited remarkable improvements in FSS-9 and UMRSA part II scores at T1 and T2, but not at T3, and also in HAMD-17 and HAMA scores at T1, T2, and T3. No significant improvement was found in the sham group.

Conclusion: High-frequency rTMS over the left DLPFC could provide short-term improvements for alleviating fatigue in patients with MSA, but the beneficial effects last no more than 4 weeks.

Noninvasive neuromodulation in Parkinson's disease: Neuroplasticity implication and therapeutic perspectives

Noninvasive brain stimulation techniques can be used to study in vivo the changes of cortical activity and plasticity in subjects with Parkinson's disease (PD). Also, an increasing number of studies have suggested a potential therapeutic effect of these techniques. High-frequency repetitive transcranial magnetic stimulation (rTMS) and anodal transcranial direct current stimulation (tDCS) represent the most used stimulation paradigms to treat motor and nonmotor symptoms of PD. Both techniques can enhance cortical activity, compensating for its reduction related to subcortical dysfunction in PD. However, the use of suboptimal stimulation parameters can lead to therapeutic failure. Clinical studies are warranted to clarify in PD the additional effects of these stimulation techniques on pharmacologic and neurorehabilitation treatments.

Theta Burst Magnetic Stimulation Improves Parkinson’s-Related Cognitive Impairment: A Randomised Controlled Study

Background. Evidence remains mixed as to the effectiveness of repetitive transcranial magnetic stimulation (rTMS) in treating mild cognitive impairment (MCI) in patients with Parkinson’s disease (PD). Objective. In this study, we examined the short- and long-term effects of patterned rTMS. Methods. We randomly assigned 35 patients with PD with MCI to two groups. One group received intermittent theta burst stimulation (iTBS; n = 20), and the other received its sham counterpart (n = 15). The stimulations were applied over the left dorsolateral prefrontal cortex for 10 consecutive weekdays. Measurements based on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Montreal Cognitive Assessment (MoCA) were conducted at three time points: at baseline, immediately after the last intervention and at 3-month follow-up. Each patient received a 99mTc-TRODAT-1 single-photon emission computed tomography (SPECT) brain scan at baseline. Results. The iTBS group exhibited significantly greater improvement than the sham group did in total RBANS and MoCA scores ( p < .001 for both) immediately after intervention and at the 3-month follow-up. Radiotracer uptake in the bilateral basal ganglion in baseline SPECT was positively correlated with response to iTBS conditioning with respect to improvements in MoCA scores ( p = .021). Conclusion. This randomised controlled trial provides evidence that a consecutive iTBS protocol can achieve a persistent and wide-ranging therapeutic effect in patients with PD with MCI.

The Entorhinal Cortex and Adult Neurogenesis in Major Depression

Depression is characterized by impairments in adult neurogenesis. Reduced hippocampal function, which is suggestive of neurogenesis impairments, is associated with depression-related phenotypes. As adult neurogenesis operates in an activity-dependent manner, disruption of hippocampal neurogenesis in depression may be a consequence of neural circuitry impairments. In particular, the entorhinal cortex is known to have a regulatory effect on the neural circuitry related to hippocampal function and adult neurogenesis. However, a comprehensive understanding of how disruption of the neural circuitry can lead to neurogenesis impairments in depression remains unclear with respect to the regulatory role of the entorhinal cortex. This review highlights recent findings suggesting neural circuitry-regulated neurogenesis, with a focus on the potential role of the entorhinal cortex in hippocampal neurogenesis in depression-related cognitive and emotional phenotypes. Taken together, these findings may provide a better understanding of the entorhinal cortex-regulated hippocampal neurogenesis model of depression.

Theta Burst Magnetic Stimulation Improves Parkinson's-Related Cognitive Impairment: A Randomised Controlled Study

Background. Evidence remains mixed as to the effectiveness of repetitive transcranial magnetic stimulation (rTMS) in treating mild cognitive impairment (MCI) in patients with Parkinson's disease (PD). Objective. In this study, we examined the short- and long-term effects of patterned rTMS. Methods. We randomly assigned 35 patients with PD with MCI to two groups. One group received intermittent theta burst stimulation (iTBS; n = 20), and the other received its sham counterpart (n = 15). The stimulations were applied over the left dorsolateral prefrontal cortex for 10 consecutive weekdays. Measurements based on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Montreal Cognitive Assessment (MoCA) were conducted at three time points: at baseline, immediately after the last intervention and at 3-month follow-up. Each patient received a 99mTc-TRODAT-1 single-photon emission computed tomography (SPECT) brain scan at baseline. Results. The iTBS group exhibited significantly greater improvement than the sham group did in total RBANS and MoCA scores (p < .001 for both) immediately after intervention and at the 3-month follow-up. Radiotracer uptake in the bilateral basal ganglion in baseline SPECT was positively correlated with response to iTBS conditioning with respect to improvements in MoCA scores (p = .021). Conclusion. This randomised controlled trial provides evidence that a consecutive iTBS protocol can achieve a persistent and wide-ranging therapeutic effect in patients with PD with MCI.

Divergent Anatomical Correlates and Functional Network Connectivity Patterns in Temporal Lobe Epilepsy with and Without Depression

Epilepsy and depression were proposed to facilitate each other reciprocally through common neurobiological anomalies, especially the prefrontal-limbic-subcortical abnormalities. Yet neuroimaging patterns of higher-order cognitive networks and neuroanatomical correlates were rarely compared in temporal lobe epilepsy patients with (TLE-D) and without depression (TLE-N). We collected T1-weighted structural and resting-state functional MRI data from 20 TLE-D, 31 TLE-N and 20 healthy controls (HCs) and performed analyses including hippocampal volume (HCV), cortical thickness, gray matter volume (GMV) and whole-brain functional network connectivity (FNC) across three groups. Imaging differences were related to clinical and psychological measurements. TLE-D demonstrated disrupted functional role of subcortical (SUB) and higher-order cognitive networks compared to TLE-N and HCs. In TLE-D, GMV in the right supplementary motor area (SMA) and FNC between the dorsal attention (DAN) and SUB were attenuated compared to TLE-N and HCs, FNC between SUB and the visual network (VIS) decreased compared to HCs. GMV in the right SMA was negatively correlated with depression severity and some symptoms. Combined, explicit emotion regulation may be impaired in TLE-D. Meanwhile, compared to HCs, TLE-N showed smaller HCVs, TLE-D and TLE-N showed smaller GMV in the medial orbital frontal gyrus and right hippocampus and hippocampal gyrus, possibly implying predisposition of epileptic activities to co-morbid depression. Our findings suggest distinct anatomical and FNC patterns in TLE-D and TLE-N. More than prefrontal-limbic-subcortical anomalies, disrupted higher-order cognitive network may contribute to depression in TLE, providing new potential treatment targets for depression and calling attention to relation between cognitive dysfunction and co-morbid depression.

The Role of White Matter Dysfunction and Leukoencephalopathy/Leukodystrophy Genes in the Aetiology of Frontotemporal Dementias: Implications for Novel Approaches to Therapeutics

Frontotemporal dementia (FTD) is a common cause of presenile dementia and is characterized by behavioural and/or language changes and progressive cognitive deficits. Genetics is an important component in the aetiology of FTD, with positive family history of dementia reported for 40% of cases. This review synthesizes current knowledge of the known major FTD genes, including C9orf72 (chromosome 9 open reading frame 72), MAPT (microtubule-associated protein tau) and GRN (granulin), and their impact on neuronal and glial pathology. Further, evidence for white matter dysfunction in the aetiology of FTD and the clinical, neuroimaging and genetic overlap between FTD and leukodystrophy/leukoencephalopathy are discussed. The review highlights the role of common variants and mutations in genes such as CSF1R (colony-stimulating factor 1 receptor), CYP27A1 (cytochrome P450 family 27 subfamily A member 1), TREM2 (triggering receptor expressed on myeloid cells 2) and TMEM106B (transmembrane protein 106B) that play an integral role in microglia and oligodendrocyte function. Finally, pharmacological and non-pharmacological approaches for enhancing remyelination are discussed in terms of future treatments of FTD.

Neural Circuitry-Neurogenesis Coupling Model of Depression

Depression is characterized by the disruption of both neural circuitry and neurogenesis. Defects in hippocampal activity and volume, indicative of reduced neurogenesis, are associated with depression-related behaviors in both humans and animals. Neurogenesis in adulthood is considered an activity-dependent process; therefore, hippocampal neurogenesis defects in depression can be a result of defective neural circuitry activity. However, the mechanistic understanding of how defective neural circuitry can induce neurogenesis defects in depression remains unclear. This review highlights the current findings supporting the neural circuitry-regulated neurogenesis, especially focusing on hippocampal neurogenesis regulated by the entorhinal cortex, with regard to memory, pattern separation, and mood. Taken together, these findings may pave the way for future progress in neural circuitry-neurogenesis coupling studies of depression.

White Matter Abnormalities in Patients With Parkinson's Disease: A Meta-Analysis of Diffusion Tensor Imaging Using Tract-Based Spatial Statistics

Background: Tract-based spatial statistics (TBSS) studies based on diffusion tensor imaging (DTI) have revealed extensive abnormalities in white matter (WM) fibers of Parkinson's disease (PD); however, the results were inconsistent. Therefore, a meta-analytical approach was used in this study to find the most prominent and replicable WM abnormalities of PD. Methods: Online databases were systematically searched for all TBSS studies comparing fractional anisotropy (FA) between patients with PD and controls. Subsequently, we performed the meta-analysis using a coordinate-based meta-analytic software called seed-based d mapping. Meanwhile, meta-regression was performed to explore the potential correlation between the alteration of FA and the clinical characteristics of PD. Results: Out of a total of 1,701 studies that were identified, 23 studies were included. Thirty datasets, including 915 patients (543 men) with PD and 836 healthy controls (449 men), were included in the current study. FA reduction was identified in the body of the corpus callosum (CC; 245 voxels; z = -1.739; p < 0.001) and the left inferior fronto-occipital fasciculus (IFOF) 118 voxels; z = -1.182; p < 0.001). Both CC and IFOF maintained significance in the sensitivity analysis. No increase in FA was identified, but the percentage of male patients with PD was positively associated with the value of FA in the body of the CC. Conclusions: Although some limitations exist, DTI is regarded as a valid way to identify the pathophysiology of PD. It could be more beneficial to integrate DTI parameters with other MRI techniques to explore brain degeneration in PD.

Effects of 10 Hz repetitive transcranial magnetic stimulation of the right dorsolateral prefrontal cortex in the vegetative state

The aim of the present study was to investigate the effects of 10 Hz repetitive transcranial magnetic stimulation (rTMS) of the right dorsolateral prefrontal cortex (DLPFC) during vegetative state (VS). Between May 2017 and November 2018, 95 patients were treated in the Coma Recovery Department of the Central Hospital of Jinzhou. According to the inclusion and exclusion criteria, a total of 32 patients in VS caused by brain injury were enrolled. The patients were assigned into rTMS and control groups in a non-randomized manner. All patients received JFK Coma Recovery Scale-Revised (CRS-R) scores and underwent motor evoked potential (MEP) latency and central motor conduction time (CMCT) measurement before the first treatment and after 20 days of treatment, which was the end of the study. Following 20 days of treatment, a significant increase was observed in the CRS-R scores of patients in the rTMS group compared with those obtained at pretreatment (P<0.001). An increase in the CRS-R scores of the control group was also observed compared with the pretreatment scores (P=0.035). The change in CRS-R scores (P<0.001) and improved conscious state rate (P=0.0016) were significantly different between the two groups. A significant decrease in MEP (P<0.001) and CMCT (P<0.001) was observed in the rTMS group compared with measurements obtained at pretreatment, whereas no significant decrease was observed in the control group (P=0.693; P=0.070). The changes in MEP (P<0.001) and CMCT (P<0.001) between the two groups were statistically significant. In conclusion, 10 Hz rTMS of the right DLPFC in early disorders of consciousness is feasible and efficient. rTMS treatment could improve patient state of awareness and accelerate patient recovery in VS.

Effect of rTMS on Parkinson's cognitive function: a systematic review and meta-analysis

Background

To evaluate the effects and optimal parameters of repetitive transcranial magnetic stimulation (rTMS) on cognition function of patients with Parkinson’s disease (PD) and to estimate which cognitive function may obtain more benefits from rTMS.

Method

The articles dealing with rTMS on cognitive function of PD patients were retrieved from the databases until April 2019. Outcomes of global cognitive function and different cognitive domains were extracted. The standardized mean differences (SMDs) with 95% confidence interval (CI) of cognitive outcome for different parameters, scales, and cognitive functions were estimated.

Results

Fourteen studies involving 173 subjects were included in this meta-analysis. A significant effect size was observed with the mini-mental state examination (MMSE) for the global cognitive outcome based on the evidence of four published articles. Further subtests for different cognitive domains demonstrated prominent effect for the executive function. The significant effect sizes for executive function were found with multiple sessions of high-frequency rTMS over frontal cortex; especially over dorsolateral prefrontal cortex (DLPFC). All of the other cognitive domains, which included memory, attention, and language ability, did not obtain significant effects.

Conclusions

Multiple sessions of high-frequency rTMS over the DLPFC may have positive effect on executive function in PD patients. Further well designed studies with large sample sizes are needed to verify our results and ascertain the long-term effects of rTMS.

Low-Frequency Repetitive Transcranial Magnetic Stimulation over Right Dorsolateral Prefrontal Cortex in Parkinson's Disease

Background

Repetitive transcranial magnetic stimulation (rTMS) is a promising therapeutic tool for Parkinson's disease (PD), and many stimulation targets have been implicated. We aim to explore whether low-frequency rTMS over the right dorsolateral prefrontal cortex (DLPFC) improves motor and nonmotor symptoms of individuals with PD.

Methods

We conducted a randomized, single-blind, sham-controlled parallel trial to compare the effect of 10 consecutive daily sessions of 1 Hz rTMS over right DLPFC on individuals with idiopathic PD between active and sham rTMS group. Primary outcomes were changes in Unified Parkinson's Disease Rating Scale (UPDRS) part III and Nonmotor Symptom Questionnaire (NMSQ). Secondary outcomes were changes in UPDRS total score, Hamilton Rating Scale for Depression (HRSD), Pittsburgh Sleep Quality Index (PSQI), and Montreal Cognitive Assessment (MoCA). Assessments were completed at baseline, after treatment, and at 1 month, 3 months, and 6 months after treatment.

Results

A total of 33 participants with PD were randomized. All participants completed the study and no severe adverse effect was noticed. Compared to baseline, active rTMS showed significant improvements in UPDRS part III and NMSQ at 1 month. Change of scores on UPDRS part III, HRSD, and PSQI persisted for 3 months after rTMS intervention. The beneficial effect on cognitive performance assessed by MoCA was maintained for at least 6 months in the follow-up. No significant changes were observed in the group with sham rTMS.

Conclusions

Low-frequency rTMS of right DLPFC could be a potential selection in managing motor and nonmotor symptoms in PD.

Motor recovery and antidepressant effects of repetitive transcranial magnetic stimulation on Parkinson disease: A PRISMA-compliant meta-analysis

BACKGROUND

Clinical symptoms of Parkinson disease (PD) included both motor and nonmotor symptoms. Previous studies indicated inconsistent results for the therapeutic effects of repetitive transcranial magnetic stimulation (rTMS) on motor and depression in PD. The study aimed to assess the therapeutic effect of rTMS with different mode on motor and depression in PD using a meta-analysis.

METHODS

Articles published before July 2019 were searched based on the following databases (PubMed, Web of Science, Medline, Embase, and Google Scholar). The therapeutic effects were assessed by computing the standard mean difference (SMD) and a 95% confidence interval (CI).

RESULTS

The present study indicated that rTMS showed significant therapeutic effects on motor in PD (SMD 2.05, 95% CI 1.57-2.53, I = 93.0%, P < .001). Both high-frequency (HF)-rTMS and low-frequency rTMS showed therapeutic effects on motor; stimulation over primary motor cortex (M1), supplementary motor area, dorsal lateral prefrontal cortex (DLPFC) or M1+DLPFC showed therapeutic effects; stimulation during "on" and "off" states showed therapeutic effects; the study showed long-term effect of rTMS on motor in PD. In addition, the study indicated that rTMS showed significant therapeutic effects on depression in PD (SMD 0.80, 95% CI 0.31-1.29, I = 89.1%, P < .001). Stimulation over left DLPFC showed significant therapeutic effects on depression in PD; only HF-rTMS showed therapeutic effects; ages, disease durations, numbers of pulses, and session durations displayed influence on the therapeutic effects of rTMS on depression in PD; the therapeutic effects on depression was long term. However, no significant difference in therapeutic effects on depression were showed between rTMS and oral Fluoxetine (SMD 0.74, 95% CI -0.83 to 2.31, I = 92.5%, P < .001).

CONCLUSION

The rTMS showed significant therapeutic effects on motor in PD. HF-rTMS showed a significant positive antidepressive effect in PD only over DLPFC.

Motor-cognitive approach and aerobic training: a synergism for rehabilitative intervention in Parkinson's disease

Parkinson's disease (PD) results in a complex deterioration of motor behavior. Effective pharmacological or surgical treatments addressing the whole spectrum of both motor and cognitive symptoms are lacking. The cumulative functional impairment may have devastating socio-economic consequences on both patients and caregivers. Comprehensive models of care based on multidisciplinary approaches may succeed in better addressing the overall complexity of PD. Neurorehabilitation is a highly promising non-pharmacological intervention for managing PD. The scientific rationale beyond rehabilitation and its practical applicability remain to be established. In the present perspective, we aim to discuss the current evidence supporting integrated motor-cognitive and aerobic rehabilitation approaches for patients with PD while suggesting a practical framework to optimize this intervention in the next future.

Impact of prefrontal intermittent theta-burst stimulation on working memory and executive function in Parkinson's disease: A double-blind sham-controlled pilot study

Cognitive impairment is a prevalent non-motor feature of Parkinson's disease (PD) which can present even in early stages of the disease. Impairments in executive processing and working memory (WM) are common and have been attributed, in part, to abnormalities within the dorsolateral prefrontal cortex (DLPFC) and broader fronto-striatal circuitry. Previous studies in cognitively normal adults have suggested intermittent Theta Burst Stimulation (iTBS), an excitatory plasticity-inducing non-invasive brain stimulation technique, can enhance these cognitive functions. Fourteen participants with a diagnosis of idiopathic PD received either Active or Sham iTBS over the left DLPFC across two separate experimental sessions as part of a double-blind sham-controlled crossover experimental design. The Berg's Card Sorting Test (BCST) and N-Back tasks, which measure executive function and WM respectively, were administered prior to iTBS and again five- and 30-minutes following stimulation. Despite being well-tolerated, iTBS failed to modulate performance on any of the cognitive outcome measures. This finding was further supported by Bayes Factor analyses which indicated moderate levels of support for the null hypothesis overall. This initial pilot study therefore does not support single-session iTBS as an efficacious method for modulating either executive processes or WM in PD. We discuss potential reasons for this finding along with directions for future research.

High-frequency repetitive transcranial magnetic stimulation to the left dorsolateral prefrontal cortex of patients with Parkinson's disease and treatment-resistant depression: a pilot study

An increasing amount of evidence is showing the therapeutic effects of rTMS on PD-related non-motor functions neuroanatomically linked to the DLPFC. This presents an ongoing need to apply an optimal combination of stimulation parameters to clinically heterogeneous patient populations, including those with neuropsychiatric problems and other comorbidities along with the neurodegenerative process. In this prospective pilot study, six patients with PD and treatment-resistant depression were thoroughly assessed and carefully monitored before, during, and after each stimulation procedure. The results can provide the basis for developing an extended rTMS protocol that is both effective and safe.

Effects of repetitive magnetic stimulation on the growth of primarily cultured hippocampus neurons in vitro and their expression of iron-containing enzymes

Background: The mechanism of action of repetitive transcranial magnetic stimulation (rTMS) involves the generation of neuronal and action potentials utilizing induced currents in time-varying magnetic fields. However, the long-lasting and effective biological impact of magnetic stimulation does not appear to be completely explained by the transient magnetic field pulses. In this context, we hypothesized magnetic stimulation may affect the expression of iron-containing enzymes in neurons, mediating the long-lasting biological effects associated with this stimulus. Methods: Primarily cultured hippocampus neurons from SD rats were used as the cell model in this study. These were randomly divided into control, sham, and magnetic stimulation groups to probe into the effect of the magnetic field directly. The latter group received 40%, 60%, and 100% maximal stimulator output Tesla (1.68, 2.52, and 4.2 T) with low-frequency rTMS (1 Hz). The expression of iron-containing enzymes (catalase and aconitase) and non-ferrous enzymes (protein kinase A) was measured with Western blotting and ELISA. Results: The survival rates of neurons in the 40%T and 60%T groups were significantly increased in comparison to the controls (P<0.05), while those in the 100%T group showed cell damage, with slightly disturbed neurite connections and decreased survival rate. Furthermore, catalase and aconitase expression was higher in all of the stimulated groups in comparison to controls (P<0.05). On the other hand, the expression of the iron-containing enzymes decreased in the 100%T group in comparison with the 40%T and 60%T groups (P<0.05). Meanwhile, the expression of protein kinase A was not significantly increased in the groups which underwent magnetic stimulation. Conclusion: rTMS may increase the expression of ferrous enzymes but does not have a strong effect on non-ferrous enzymes. Excessive intensity of magnetic stimulation may reduce neuronal survival rate and affect the expression of iron-containing enzymes. The mechanism underlying the lasting effect of rTMS may be related to the increase of ferriferous expression induced by magnetic stimulation, with a clear correlation with stimulation intensity.