Beneficial effect of repetitive transcranial magnetic stimulation combined with cognitive training for the treatment of Alzheimer's disease: a proof of concept study

Harnessing Brainwave Entrainment: A Non-invasive Strategy To Alleviate Neurological Disorder Symptoms

From 1990-2019, the burden of neurological disorders varied considerably across countries and regions. Psychiatric disorders, often emerging in early to mid-adulthood, are linked to late-life neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. Individuals with conditions such as Major Depressive Disorder, Anxiety Disorder, Schizophrenia, and Bipolar Disorder face up to four times higher risk of developing neurodegenerative disorders. Contrarily, 65 % of those with neurodegenerative conditions experience severe psychiatric symptoms during their illness. Further, the limitation of medical resources continues to make this burden a significant global and local challenge. Therefore, brainwave entrainment provides therapeutic avenues for improving the symptoms of diseases. Brainwaves are rhythmic oscillations produced either spontaneously or in response to stimuli. Key brainwave patterns include gamma, beta, alpha, theta, and delta waves, yet the underlying physiological mechanisms and the brain's ability to shift between these dynamic states remain areas for further exploration. In neurological disorders, brainwaves are often disrupted, a phenomenon termed "oscillopathy". However, distinguishing these impaired oscillations from the natural variability in brainwave activity across different regions and functional states poses significant challenges. Brainwave-mediated therapeutics represents a promising research field aimed at correcting dysfunctional oscillations. Herein, we discuss a range of non-invasive techniques such as non-invasive brain stimulation (NIBS), neurologic music therapy (NMT), gamma stimulation, and somatosensory interventions using light, sound, and visual stimuli. These approaches, with their minimal side effects and cost-effectiveness, offer potential therapeutic benefits. When integrated, they may not only help in delaying disease progression but also contribute to the development of innovative medical devices for neurological care.

Toward a neurocircuit-based sequential transcranial magnetic stimulation treatment of pediatric bipolar II disorder

BACKGROUND

Abnormalities in large-scale neuronal networks-the frontoparietal central executive network (CEN)-are consistent findings in bipolar disorder and potential therapeutic targets for transcranial magnetic stimulation (TMS).

OBJECTIVE

The present study aimed to assess the effects of CEN neurocircuit-based sequential TMS on the clinical symptoms and cognitive functions of adolescents with bipolar II disorder.

METHODS

The study was a single-blinded, randomized, placebo-control trial. Participants with DSM-5-defined bipolar disorder II were recruited and randomized to receive either a sham treatment (n = 20) or an active TMS treatment (n = 22). The active group patients were taking medication, with intermittent theta burst stimulation (iTBS) treatment provided as adjunctive treatment targeting the left DLPFC, the left ITG, and the left PPC nodes consecutively. Patients completed the measurements of HAMD and the Das-Naglieri Cognition Assessment System at baseline and 3 weeks after the intervention.

RESULTS

A significant group-by-time interaction was observed in the HAMD, total cognition, and planning. Post-hoc analysis revealed that patients in the active group significantly improved HAMD scores following neurostimulation. Moreover, within-subject analysis indicated that the active group significantly improved in scores of total cognition and planning, while the sham group did not. No significant differences were seen in the other cognitive measures.

CONCLUSION

The neurocircuit-based sequential TMS protocol targeting three CEN nodes, in conjunction with medication, safely and effectively improved depressive symptoms and cognitive function in adolescents with bipolar II disorder.

Efficacy and safety of transcranial magnetic stimulation on cognition in mild cognitive impairment, Alzheimer's disease, Alzheimer's disease-related dementias, and other cognitive disorders: a systematic review and meta-analysis

OBJECTIVE

We aim to analyze the efficacy and safety of TMS on cognition in mild cognitive impairment (MCI), Alzheimer's disease (AD), AD-related dementias, and nondementia conditions with comorbid cognitive impairment.

DESIGN

Systematic review, Meta-Analysis SETTING: We searched MEDLINE, Embase, Cochrane database, APA PsycINFO, Web of Science, and Scopus from January 1, 2000, to February 9, 2023.

PARTICIPANTS AND INTERVENTIONS

RCTs, open-label, and case series studies reporting cognitive outcomes following TMS intervention were included.

MEASUREMENT

Cognitive and safety outcomes were measured. Cochrane Risk of Bias for RCTs and MINORS (Methodological Index for Non-Randomized Studies) criteria were used to evaluate study quality. This study was registered with PROSPERO (CRD42022326423).

RESULTS

The systematic review included 143 studies (n = 5,800 participants) worldwide, encompassing 94 RCTs, 43 open-label prospective, 3 open-label retrospective, and 3 case series. The meta-analysis included 25 RCTs in MCI and AD. Collectively, these studies provide evidence of improved global and specific cognitive measures with TMS across diagnostic groups. Only 2 studies (among 143) reported 4 adverse events of seizures: 3 were deemed TMS unrelated and another resolved with coil repositioning. Meta-analysis showed large effect sizes on global cognition (Mini-Mental State Examination (SMD = 0.80 [0.26, 1.33], p = 0.003), Montreal Cognitive Assessment (SMD = 0.85 [0.26, 1.44], p = 0.005), Alzheimer's Disease Assessment Scale-Cognitive Subscale (SMD = -0.96 [-1.32, -0.60], p < 0.001)) in MCI and AD, although with significant heterogeneity.

CONCLUSION

The reviewed studies provide favorable evidence of improved cognition with TMS across all groups with cognitive impairment. TMS was safe and well tolerated with infrequent serious adverse events.

Treating Alzheimer's disease with brain stimulation: From preclinical models to non-invasive stimulation in humans

Alzheimer's disease (AD) is a severe and progressive neurodegenerative condition that exerts detrimental effects on brain function. As of now, there is no effective treatment for AD patients. This review explores two distinct avenues of research. The first revolves around the use of animal studies and preclinical models to gain insights into AD's underlying mechanisms and potential treatment strategies. Specifically, it delves into the effectiveness of interventions such as Optogenetics and Chemogenetics, shedding light on their implications for understanding pathophysiological mechanisms and potential therapeutic applications. The second avenue focuses on non-invasive brain stimulation (NiBS) techniques in the context of AD. Evidence suggests that NiBS can successfully modulate cognitive functions associated with various neurological and neuropsychiatric disorders, including AD, as demonstrated by promising findings. Here, we critically assessed recent findings in AD research belonging to these lines of research and discuss their potential impact on the clinical horizon of AD treatment. These multifaceted approaches offer hope for advancing our comprehension of AD pathology and developing novel therapeutic interventions.

Efficacy of rTMS Combined with Cognitive and Language Training in People Living with Alzheimer's Disease: A Systematic Review

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation method that has been suggested as a possible treatment method for cognitive impairment in patients with Alzheimer's Disease (pwAD), similar to multidomain cognitive training (CT). The effectiveness, however, of combining these techniques for pwAD remains controversial due to the variability in rTMS parameters, differences in CT protocol designs-many of which neglect the language domain-and the inclusion of patients at various stages of Alzheimer's Disease (AD) and with different types of dementia. The current review aims to evaluate the cognitive benefits of combining rTMS with CT, including language training, for individuals with mild to moderate AD. An extensive literature search was conducted in PubMed, Google Scholar, and the Cochrane Library with relevant terms, resulting in nine studies with a total of 290 participants [190 in the Active Group (AG) and 100 in the Control Group (CG)]. The comprehensive review of the articles revealed that the combined treatment improved global cognitive function, as well as neurocognitive, neuropsychiatric, and quality of life in the AG. Nevertheless, these results should be interpreted cautiously, given the relatively small number of existing studies on this specific combination.

Effect of transcranial direct current stimulation and transcranial magnetic stimulation on the cognitive function of individuals with Alzheimer's disease: a systematic review with meta-analysis and meta-regression

OBJECTIVE

To analyze the effects of transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) on the cognitive function of individuals with Alzheimer's disease (AD).

METHODS

This systematic review with meta-analysis and meta-regression included randomized clinical trials published until 05/2022. We included studies conducted with individuals with AD of both sexes, aged between 55 and 85 years, treated with tDCS, TMS, or both.

RESULTS

Twenty-one studies were included in the systematic review and sixteen in the meta-analysis. Meta-regression suggested a significant influence of anodic tDCS with current intensity of 1.5 mA on cognitive function. Significant results were found with treatment frequencies of three and five days a week for two weeks. Subgroup analysis found that anodic tDCS influences cognitive function, regardless of AD stage. Similar was observed for TMS using a frequency of 20 Hz and current intensity of 90% of the resting motor threshold.

DISCUSSION

Anodal tDCS and 20 Hz TMS have demonstrated the ability to improve cognitive function in AD by modulating neural activity. These therapies are safe and well-tolerated, offering promise as adjuncts to available pharmacological treatments. Studies with greater methodological rigor and parameter standardization are warranted. Comprehensive investigations involving neuroimaging techniques may provide a better understanding of the interaction between induced electrical fields and the complex neural networks affected in AD, paving the way for more personalized and effective neurostimulation approaches.

A randomised controlled trial investigating the causal role of the medial prefrontal cortex in mediating self-agency during speech monitoring and reality monitoring

Self-agency is the awareness of being the agent of one's own thoughts and actions. Self-agency is essential for interacting with the outside world (reality-monitoring). The medial prefrontal cortex (mPFC) is thought to be one neural correlate of self-agency. We investigated whether mPFC activity can causally modulate self-agency on two different tasks of speech-monitoring and reality-monitoring. The experience of self-agency is thought to result from making reliable predictions about the expected outcomes of one's own actions. This self-prediction ability is necessary for the encoding and memory retrieval of one's own thoughts during reality-monitoring to enable accurate judgments of self-agency. This self-prediction ability is also necessary for speech-monitoring where speakers consistently compare auditory feedback (what we hear ourselves say) with what we expect to hear while speaking. In this study, 30 healthy participants are assigned to either 10 Hz repetitive transcranial magnetic stimulation (rTMS) to enhance mPFC excitability (N = 15) or 10 Hz rTMS targeting a distal temporoparietal site (N = 15). High-frequency rTMS to mPFC enhanced self-predictions during speech-monitoring that predicted improved self-agency judgments during reality-monitoring. This is the first study to provide robust evidence for mPFC underlying a causal role in self-agency, that results from the fundamental ability of improving self-predictions across two different tasks.

Neuroprotective effects of repetitive transcranial magnetic stimulation on Alzheimer's disease: Undetermined therapeutic protocols and mechanisms

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by gradual deterioration of cognitive functions, for which an effective treatment is currently unavailable. Repetitive transcranial magnetic stimulation (rTMS), a well‐established noninvasive brain stimulation method, is utilized in clinical settings to address various neuropsychiatric conditions, such as depression, neuropathic pain, and poststroke dysfunction. Increasing evidence suggests that rTMS may enhance cognitive abilities in individuals with AD. However, its optimal therapeutic protocols and precise mechanisms are currently unknown, impeding its clinical implementation. In the present review, we aimed to summarize and discuss the efficacy‐related parameters in rTMS treatment, encompassing stimulus frequency, stimulus pattern, stimulus intensity, and the configuration of the stimulus coil. Furthermore, we reviewed promising rTMS therapeutic protocols involving various combinations of these factors, that were examined in clinical studies. Based on our analysis, we propose that a multisite high‐frequency rTMS (HF‐rTMS) regimen has value in AD therapy, and that promising single‐site protocols, such as HF‐rTMS, applied over the left dorsolateral prefrontal cortex, precuneus, or cerebellum are required to be validated in larger clinical studies. Lastly, we provide a comprehensive review of the potential mechanisms underlying the neuroprotective effects of rTMS on cognition in AD in terms of brain network modulation as well as cellular and molecular reactions. In conclusion, the interaction of diverse mechanisms may be responsible for the total therapeutic effect of rTMS on AD. This review provides theoretical and practical evidence for the future clinical application and scientific research of rTMS in AD.

Causal role of medial superior frontal cortex on enhancing neural information flow and self-agency judgments in the self-agency network

Self-agency is being aware of oneself as the agent of one's thoughts and actions. Self-agency is necessary for successful interactions with the outside world (reality-monitoring). Prior research has shown that the medial superior prefrontal gyri (mPFC/SFG) may represent one neural correlate underlying self-agency judgments. However, the causal relationship remains unknown. Here, we applied high-frequency 10Hz repetitive transcranial magnetic stimulation (rTMS) to modulate the excitability of the mPFC/SFG site that we have previously shown to mediate self-agency. For the first time, we delineate causal neural mechanisms, revealing precisely how rTMS modulates SFG excitability and impacts directional neural information flow in the self-agency network by implementing innovative magnetoencephalography (MEG) phase-transfer entropy (PTE) metrics, measured from pre-to-post rTMS. We found that, compared to control rTMS, enhancing SFG excitability by rTMS induced significant increases in information flow between SFG and specific cingulate and paracentral regions in the self-agency network in delta-theta, alpha, and gamma bands, which predicted improved self-agency judgments. This is the first multimodal imaging study in which we implement MEG PTE metrics of 5D imaging of space, frequency and time, to provide cutting-edge analyses of the causal neural mechanisms of how rTMS enhances SFG excitability and improves neural information flow between distinct regions in the self-agency network to potentiate improved self-agency judgments. Our findings provide a novel perspective for investigating causal neural mechanisms underlying self-agency and create a path towards developing novel neuromodulation interventions to improve self-agency that will be particularly useful for patients with psychosis who exhibit severe impairments in self-agency.

Brain Stimulation in Alzheimer's Disease Trials

Alzheimer's disease (AD) continues to lack definitive curative therapies, necessitating an urgent exploration of innovative approaches. This review provides a comprehensive analysis of recent clinical trials focusing on invasive and non-invasive brain stimulation techniques as potential interventions for AD. Deep brain stimulation (DBS), repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), and transcranial alternating current stimulation (tACS) are evaluated for their therapeutic efficacy, safety, and applicability. DBS, though invasive, has shown promising results in mitigating cognitive decline, but concerns over surgical risks and long-term effects persist. On the other hand, non-invasive methods like rTMS, tDCS, and tACS have demonstrated potential in enhancing cognitive performance and delaying disease progression, with minimal side effects, but with varied consistency. The evidence hints towards an individualized, patient-centric approach to brain stimulation, considering factors such as disease stage, genetic traits, and stimulation parameters. The review also highlights emerging technologies and potential future directions, emphasizing the need for larger, multi-center trials to confirm preliminary findings and establish robust clinical guidelines. In conclusion, while brain stimulation techniques present a promising avenue in AD therapy, further research is imperative for more comprehensive understanding and successful clinical implementation. Through this review, we aim to catalyze the scientific discourse and stimulate further investigation into these novel interventions for AD.

Unlocking the Potential of Repetitive Transcranial Magnetic Stimulation in Alzheimer's Disease: A Meta-Analysis of Randomized Clinical Trials to Optimize Intervention Strategies

Background

Repetitive transcranial magnetic stimulation (rTMS) is an advanced and noninvasive technology that uses pulse stimulation to treat cognitive impairment. However, its specific effects have always been mixed with those of cognitive training, and the optimal parameter for Alzheimer's disease (AD) intervention is still ambiguous.

Objective

This study aimed to summarize the therapeutic effects of pure rTMS on AD, excluding the influence of cognitive training, and to develop a preliminary rTMS treatment plan.

Methods

Between 1 January 2010 and 28 February 2023, we screened randomized controlled clinical trials from five databases (PubMed, Web of Science, Embase, Cochrane, and ClinicalTrials. gov). We conducted a meta-analysis and systematic review of treatment outcomes and rTMS treatment parameters.

Result

A total of 4,606 articles were retrieved. After applying the inclusion and exclusion criteria, 16 articles, comprising 655 participants (308 males and 337 females), were included in the final analysis. The findings revealed that rTMS significantly enhances both global cognitive ability (p = 0.0002, SMD = 0.43, 95% CI = 0.20-0.66) and memory (p = 0.009, SMD = 0.37, 95% CI = 0.09-0.65). Based on follow-up periods of at least 6 weeks, the following stimulation protocols have demonstrated efficacy for AD: stimulation sites (single or multiple targets), frequency (20 Hz), stimulation time (1-2 s), interval (20-30 s), single pulses (≤2500), total pulses (>20000), duration (≥3 weeks), and sessions (≥20).

Conclusions

This study suggests that rTMS may be an effective treatment option for patients with AD, and its potential therapeutic capabilities should be further developed in the future.

rTMS reduces delta and increases theta oscillations in Alzheimer's disease: A visual-evoked and event-related potentials study

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) has emerged as a promising alternative therapy for Alzheimer's disease (AD) due to its ability to modulate neural networks and enhance cognitive function. This treatment offers the unique advantage of enabling real-time monitoring of immediate cognitive effects and dynamic brain changes through electroencephalography (EEG).

OBJECTIVE

This study focused on exploring the effects of left parietal rTMS stimulation on visual-evoked potentials (VEP) and visual event-related potentials (VERP) in AD patients.

METHODS

Sixteen AD patients were recruited for this longitudinal study. EEG data were collected within a Faraday cage both pre- and post-rTMS to evaluate its impact on potentials.

RESULTS

Significant alterations were found in both VEP and VERP oscillations. Specifically, delta power in VEP decreased, while theta power in VERP increased post-rTMS, indicating a modulation of brain activities.

DISCUSSION

These findings confirm the positive modulatory impact of rTMS on brain activities in AD, evidenced by improved cognitive scores. They align with previous studies highlighting the potential of rTMS in managing hyperexcitability and oscillatory disturbances in the AD cortex.

CONCLUSION

Cognitive improvements post-rTMS endorse its potential as a promising neuromodulatory treatment for cognitive enhancement in AD, thereby providing critical insights into the neurophysiological anomalies in AD and possible therapeutic avenues.

Repetitive transcranial magnetic stimulation for apathy in patients with neurodegenerative conditions, cognitive impairment, stroke, and traumatic brain injury: a systematic review

Background

We aimed to determine the effects and tolerability of repetitive transcranial magnetic stimulation (rTMS) on apathy in patients with neurodegenerative conditions, mild cognitive impairment (MCI), stroke, and traumatic brain injury (TBI) via systematic review.

Methods

We conducted a systematic search in major electronic health databases, including PubMed, Scopus, and PsycINFO, covering the period from inception to June 2023. Comparative clinical trials and cohort studies, and studies with before-after designs were considered for inclusion. We used the Cochrane Risk of Bias and the National Institutes of Health (NIH) tools to assess methodological quality.

Results

Out of 258 records identified, 14 studies met our eligibility criteria (11 randomized controlled trials (RCT) and 3 studies utilized before-and-after designs) with a total of 418 patients (overall female-to-male ratio 1:1.17) included in the review. The overall methodological quality of the included studies was assessed to be fair to good. The stimulation parameters used varied considerably across the studies. The summary findings of our review indicate the following observations on the effects of rTMS on apathy: (1) the results of all included studies in Alzheimer's disease investigating the effects of rTMS on apathy have consistently shown a positive impact on apathy; (2) the majority of studies conducted in Parkinson's disease have not found statistically significant results; (3) a single study (RCT) on patients with primary progressive aphasia demonstrated significant beneficial effects of rTMS on apathy; (4) the trials conducted on individuals with MCI yielded varying conclusions; (5) one study (RCT) in chronic stroke suggested that rTMS might have the potential to improve apathy; (6) one study conducted on individuals with mild TBI did not find a significant favorable association on apathy; and (7) the use of different rTMS protocols on the populations described is generally safe.

Conclusion

The feasibility of utilizing rTMS as a treatment for apathy has been suggested in this review. Overall, limited evidence suggests that rTMS intervention may have the potential to modify apathy among patients with AD, PPA, MCI and chronic stroke, but less so in PD and mild TBI. These findings require confirmation by larger, well-designed clinical trials.

Treatment of cognitive and mood disorders secondary to traumatic brain injury by the association of bilateral occipital nerve stimulation and a combined protocol of multisite repetitive transcranial magnetic stimulation and cognitive training: A case report

Purpose

Cognitive impairment secondary to traumatic brain injury (TBI) is difficult to treat and usually results in severe disability.

Method

A 48-year-old man presented with chronic refractory headaches and persistent disabling cognitive impairment after TBI. He was first treated with occipital nerve stimulation (ONS) implanted bilaterally to relieve headaches (8 years after the head trauma). Two years later, he was treated with a 6-week protocol combining repetitive transcranial magnetic stimulation (rTMS) delivered to multiple cortical sites (prefrontal cortex, language areas, and areas involved in visuo-spatial functions) and computerized cognitive training (CogT) (targeting memory, language, and visuo-spatial functions) to improve cognitive performance.

Results

Executive and cognitive functions (attention, ability to perform calculations, and verbal fluency) improved in association with pain relief after ONS (33-42% improvement) and then improved even more after the rTMS-CogT protocol with an additional improvement of 36-40% on apathy, depression, and anxiety, leading to a significant reduction in caregiver burden. The functional improvement persisted and even increased at 6 months after the end of the rTMS-CogT procedure (10 years after the onset of TBI and 2 years after ONS implantation).

Conclusion

This is the first observation describing sustained improvement in post-TBI refractory headache, depression, and cognitive impairment by the association of bilaterally implanted ONS and a combined procedure of multisite rTMS and CogT to target various brain functions.

Transcranial Magnetic Stimulation (rTMS) on the Precuneus in Alzheimer's Disease: A Literature Review

The current literature review aimed to evaluate the effectiveness of rTMS on the precuneus as a potential treatment for Alzheimer's disease (AD). Although the number of studies specifically targeting the precuneus is limited, the results from this review suggest the potential benefits of this approach. Future studies should focus on exploring the long-term effects of rTMS on the precuneus in Alzheimer's disease patients, as well as determining the optimal stimulation parameters and protocols for this population. Additionally, investigating the effects of rTMS on the precuneus in combination with other brain regions implicated in AD may provide valuable insights into the development of effective treatment for this debilitating neurodegenerative disorder.

A randomised controlled trial investigating the causal role of the medial prefrontal cortex in mediating self-agency during speech monitoring and reality monitoring

Self-agency is being aware of oneself as the agent of one's thoughts and actions. Self agency is necessary for successful interactions with the external world (reality-monitoring). The medial prefrontal cortex (mPFC) is considered to represent one neural correlate underlying self-agency. We investigated whether mPFC activity can causally modulate self-agency on two different tasks involving speech-monitoring and reality-monitoring. The experience of self-agency is thought to result from being able to reliably predict the sensory outcomes of one's own actions. This self-prediction ability is necessary for successfully encoding and recalling one's own thoughts to enable accurate self-agency judgments during reality-monitoring tasks. This self-prediction ability is also necessary during speech-monitoring tasks where speakers compare what we hear ourselves say in auditory feedback with what we predict we will hear while speaking. In this randomised-controlled study, heathy controls (HC) are assigned to either high-frequency transcranial magnetic stimulation (TMS) to enhance mPFC excitability or TMS targeting a control site. After TMS to mPFC, HC improved self-predictions during speech-monitoring tasks that predicted improved self-agency judgments during different reality-monitoring tasks. These first-in-kind findings demonstrate the mechanisms of how mPFC plays a causal role in self-agency that results from the fundamental ability of improving self-predictions across two different tasks.

Multisite rTMS combined with cognitive training modulates effective connectivity in patients with Alzheimer's disease

Purpose

To investigate the effective connectivity (EC) changes after multisite repetitive transcranial magnetic stimulation (rTMS) combined with cognitive training (COG).

Method

We selected 51 patients with mild or moderate Alzheimer's disease (AD) and delivered 10 Hz rTMS over the left dorsal lateral prefrontal cortex (DLPFC) and the lateral temporal lobe (LTL) combined with COG or sham stimulation for 4 weeks. The selected AD patients were divided into real (real rTMS+COG, n = 11) or sham (sham rTMS+COG, n = 8) groups to undergo neuropsychological assessment, resting-state fMRI, and 3D brain structural imaging before (T0), immediately at the end of treatment (T4), and 4 weeks after treatment (T8). A 2 × 3 factorial design with "time" as the within-subjects factor (three levels: T0, T4, and T8) and "group" as the between-subjects factor (two levels: real and sham) was used to investigate the EC changes related to the stimulation targets in the rest of the brain, as well as the causal interactions among seven resting-state networks based on Granger causality analysis (GCA).

Results

At the voxel level, the EC changes from the left DLPFC out to the left inferior parietal lobe and the left superior frontal gyrus, as well as from the left LTL out to the left orbital frontal cortex, had a significant group × time interaction effect. At the network level, a significant interaction effect was identified in the increase in EC from the limbic network out to the default mode network. The decrease in EC at the voxel level and the increase in EC at the network level were both associated with the improved ability to perform activities of daily living and cognitive function.

Conclusion

Multisite rTMS combined with cognitive training can modulate effective connectivity in patients with AD, resulting in improved ability to perform activities of daily living and cognitive function.

Cerebrolysin and repetitive transcranial magnetic stimulation (rTMS) in patients with traumatic brain injury: a three-arm randomized trial

Introduction

Traumatic brain injury (TBI) is a major public health problem affecting millions worldwide. Despite significant advances in medical care, there are limited effective interventions for improving cognitive and functional outcomes in TBI patients.

Methods

This randomized controlled trial investigated the safety and efficacy of combining repetitive transcranial magnetic stimulation (rTMS) and Cerebrolysin in improving cognitive and functional outcomes in TBI patients. Ninety-three patients with TBI were randomized to receive either Cerebrolysin and rTMS (CRB + rTMS), Cerebrolysin and sham stimulation (CRB + SHM), or placebo and sham stimulation (PLC + SHM). The primary outcome measures were the composite cognitive outcome scores at 3 and 6 months after TBI. Safety and tolerability were also assessed.

Results

The study results demonstrated that the combined intervention of rTMS and Cerebrolysin was safe and well-tolerated by patients with TBI. Although no statistically significant differences were observed in the primary outcome measures, the descriptive trends in the study support existing literature on the efficacy and safety of rTMS and Cerebrolysin.

Discussion

The findings of this study suggest that rTMS and Cerebrolysin may be effective interventions for improving cognitive and functional outcomes in TBI patients. However, limitations of the study, such as the small sample size and exclusion of specific patient populations, should be considered when interpreting the results. This study provides preliminary evidence for the safety and potential efficacy of combining rTMS and Cerebrolysin in improving cognitive and functional outcomes in TBI patients. The study highlights the importance of multidisciplinary approaches in TBI rehabilitation and the potential for combining neuropsychological measurements and interventions to optimize patient outcomes.

Conclusion

Further research is needed to establish these findings' generalizability and identify the optimal dosages and treatment protocols for rTMS and Cerebrolysin.

Is blood-brain barrier a probable mediator of non-invasive brain stimulation effects on Alzheimer's disease?

Alzheimer's disease (AD) is a complex neurodegenerative disease with no existing treatment leading to full recovery. The blood-brain barrier (BBB) breakdown usually precedes the advent of first symptoms in AD and accompanies the progression of the disease. At the same time deliberate BBB opening may be beneficial for drug delivery in AD. Non-invasive brain stimulation (NIBS) techniques, primarily transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), have shown multiple evidence of being able to alleviate symptoms of AD. Currently, TMS/tDCS mechanisms are mostly investigated in terms of their neuronal effects, while their possible non-neuronal effects, including mitigation of the BBB disruption, are less studied. We argue that studies of TMS/tDCS effects on the BBB in AD are necessary to boost the effectiveness of neuromodulation in AD. Moreover, such studies are important considering the safety issues of TMS/tDCS use in the advanced AD stages when the BBB is usually dramatically deteriorated. Here, we elucidate the evidence of NIBS-induced BBB opening and closing in various models from in vitro to humans, and highlight its importance in AD.

Effects of repetitive paired associative stimulation on brain plasticity and working memory in Alzheimer's disease: a pilot randomized double-blind-controlled trial

DESIGN

Pilot randomized double-blind-controlled trial of repetitive paired associative stimulation (rPAS), a paradigm that combines transcranial magnetic stimulation (TMS) of the dorsolateral prefrontal cortex (DLPFC) with peripheral median nerve stimulation.

OBJECTIVES

To study the impact of rPAS on DLPFC plasticity and working memory performance in Alzheimer's disease (AD).

METHODS

Thirty-two patients with AD (females = 16), mean (SD) age = 76.4 (6.3) years were randomized 1:1 to receive a 2-week (5 days/week) course of active or control rPAS. DLPFC plasticity was assessed using single session PAS combined with electroencephalography (EEG) at baseline and on days 1, 7, and 14 post-rPAS. Working memory and theta-gamma coupling were assessed at the same time points using the N-back task and EEG.

RESULTS

There were no significant differences between the active and control rPAS groups on DLPFC plasticity or working memory performance after the rPAS intervention. There were significant main effects of time on DLPFC plasticity, working memory, and theta-gamma coupling, only for the active rPAS group. Further, on post hoc within-group analyses done to generate hypotheses for future research, as compared to baseline, only the rPAS group improved on post-rPAS day 1 on all three indices. Finally, there was a positive correlation between working memory performance and theta-gamma coupling.

CONCLUSIONS

This study did not show a beneficial effect of rPAS for DLPFC plasticity or working memory in AD. However, post hoc analyses showed promising results favoring rPAS and supporting further research on this topic. (Clinicaltrials.gov-NCT01847586).

Cerebral blood flow changes induced by high-frequency repetitive transcranial magnetic stimulation combined with cognitive training in Alzheimer's disease

Background and purpose

Hypoperfusion of the posterior cingulate cortex (PCC) and precuneus has consistently been reported in patients with Alzheimer's disease (AD). Repetitive transcranial magnetic stimulation (rTMS) combined with cognitive training (COG) is effective in alleviating the symptoms of patients with mild AD. This study investigated the effects of rTMS-COG therapy on cerebral blood flow (CBF), with a special interest in the PCC/precuneus, and whether observed CBF changes are associated with changes in neuropsychological assessments in AD.

Materials and methods

Twenty-one patients with mild or moderate AD were randomly divided into real rTMS (n = 11) and sham treatment (n = 10) groups, both combined with COG. Neuro-navigated 10 Hz rTMS was used to stimulate the left dorsolateral prefrontal cortex (DLPFC) and then the left lateral temporal lobe (LTL) for 20 min each day for 4 weeks in the real rTMS group. All patients with AD underwent neuropsychological assessment, pseudo-continuous arterial spin labeling, and structural 3D T1-weighted MRI before treatment (T0), immediately after treatment (T1), and 4 weeks after treatment (T2). CBF in the precuneus, PCC, and stimulation targets at the region-of-interest (ROI) level, as well as whole-brain CBF changes at the voxel level, were compared between the two groups at three timepoints.

Results

rTMS-COG therapy revealed significant group × time interactions for the Mini-Mental State Examination (F = 5.339, p = 0.023, η² = 0.433) and activities of daily living (F = 5.409, p = 0.039, η² = 0.436) scores. The regional CBF in the precuneus showed a significant group × time interaction (F = 5.833, p = 0.027, η² = 0.593). For voxel-level analysis, a significant group main effect was found in the left limbic lobe cluster, with the maximal peak in the left parahippocampus (p < 0.001, uncorrected, peak at [-16 -8 -24]). Simple effects analysis indicated that rTMS-COG therapy induced a decrease in CBF in the precuneus at T1 (p = 0.007) and an increase in the left parahippocampus at T2 (p=0.008). CBF decrease in the precuneus was correlated with better cognitive function immediately after treatment (T1) (r =-0.732, p=0.025).

Conclusion

Neuropsychological assessments showed immediate and long-term effects on cognitive function and activities of daily living after rTMS-COG therapy. CBF changes induced by high-frequency rTMS-COG therapy are region-dependent, showing immediate effects in the precuneus and long-term effects in the left parahippocampus. These results provide imaging evidence to understand the underlying neurobiological mechanism for the application of rTMS-COG in AD.

Is non-invasive brain stimulation effective for cognitive enhancement in Alzheimer's disease? An updated meta-analysis

OBJECTIVE

Alzheimer's disease dementia (AD) and its preclinical stage, mild cognitive impairment (MCI), are critical issues confronting the aging society. Non-invasive brain stimulation (NIBS) techniques have the potential to be effective tools for enhancing cognitive functioning. The main objective of our meta-analysis was to quantify and update the status of the efficacy of repetitive Transcranial Magnetic Stimulation (rTMS) and Transcranial Direct Current Stimulation (tDCS) when applied in AD and MCI.

METHODS

The systematic literature search was conducted in PubMed and Web of Science according to PRISMA statement.

RESULTS

Pooled effect sizes (Hedges' g) from 32 studies were analyzed using random effect models. We found both, rTMS and tDCS to have significant immediate cognition-enhancing effect in AD with rTMS inducing also beneficial long-term effects. We found no evidence for synergistic effect of cognitive training with NIBS.

CONCLUSIONS

In AD a clinical recommendation can be made for NEURO-AD^TM system and for high-frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC) as probably effective protocols (B-level of evidence) and for anodal tDCS over the left DLPFC as a possibly effective.

SIGNIFICANCE

According to scientific literature, NIBS may be an effective method for improving cognition in AD and possibly in MCI.

Cortical hyperexcitability and plasticity in Alzheimer's disease: developments in understanding and management

INTRODUCTION

Transcranial magnetic stimulation (TMS) is a non-invasive neurophysiological tool that provides important insights into Alzheimer's Disease (AD). A significant body of work utilizing TMS techniques has explored the pathophysiological relevance of cortical hyperexcitability and plasticity in AD and their modulation in novel therapies.

AREAS COVERED

This review examines the technique of TMS, the use of TMS to examine specific features of cortical excitability and the use of TMS techniques to modulate cortical function. A search was performed utilizing the PubMed database to identify key studies utilizing TMS to examine cortical hyperexcitability and plasticity in Alzheimer's dementia. We then translate this understanding to the study of Alzheimer's disease pathophysiology, examining the underlying neurophysiologic links contributing to these twin signatures, cortical hyperexcitability and abnormal plasticity, in the cortical dysfunction characterizing AD. Finally, we examine utilization of TMS excitability to guide targeted therapies and, through the use of repetitive TMS (rTMS), modulate cortical plasticity.

EXPERT OPINION

The examination of cortical hyperexcitability and plasticity with TMS has potential to optimize and expand the window of therapeutic interventions in AD, though remains at relatively early stage of development.

Randomized, sham-controlled, clinical trial of repetitive transcranial magnetic stimulation for patients with Alzheimer's dementia in Japan

Background

Several medications have been applied to Alzheimer's dementia patients (AD) but their efficacies have been insufficient. The efficacy and safety of 4 weeks of repetitive transcranial magnetic stimulation (rTMS) in Japanese AD were evaluated in this exploratory clinical trial.

Methods

Forty-two patients, aged 60-93 years (average, 76.4 years), who were taking medication (> 6 months) and had Mini-Mental State Examination (MMSE) scores ≤ 25 and Clinical Dementia Rating Scale scores (CDR-J) of 1 or 2, were enrolled in this single-center, prospective, randomized, three-arm study [i.e., 120% resting motor threshold (120% RMT), 90% RMT for the bilateral dorsolateral prefrontal cortex, and Sham]. Alzheimer's Disease Assessment Scale-Japanese Cognitive (ADAS-J cog), Montreal Cognitive Assessment (MoCA-J), Clinical Global Impression of Change (CGIC), Neuropsychiatric inventory (NPI), and EuroQOL 5 Dimensions 5-Level (EQ-5D-5L) were administered. The primary endpoint was the mean change from baseline in the MMSE score (week 4). An active rTMS session involved applying 15 trains bilaterally (40 pulses/train at 10 Hz; intertrain interval, 26 s). Participants received ≥ 8 interventions within the first 2 weeks and at least one intervention weekly in the 3rd and 4th weeks. Full Analysis set (FAS) included 40 patients [120% RMT (n = 15), 90% RMT (n = 13), and Sham (n = 12)].

Results

In the FAS, MMSE, ADAS-J cog, MoCA-J, CDR-J, CGIC, NPI, and EQ-5D-5L scores between the three groups were not significantly different. Two patients were erroneously switched between the 120% RMT and 90% RMT groups, therefore, "as treated" patients were mainly analyzed. Post hoc analysis revealed significant treatment efficacy in participants with MMSE scores ≥ 15, favoring the 120% RMT group over the Sham group. Responder analysis revealed 41.7% of the 120% RMT group had a ≥ 3-point improvement in the ADAS-J cog versus 0% in the Sham group (Fisher's exact test, p = 0.045). The MoCA-J showed the same tendency but was not significant. Efficacy disappeared in week 20, based on the ADAS-cog and MoCA-J. No intervention-related serious adverse events occurred.

Conclusion

This paper is the first report of using rTMS in Japanese AD patients. The treatment seems safe and moderate-mild stage AD should be target population of pivotal clinical trial with 120% RMT rTMS.

Brain Stimulation for Improving Sleep and Memory

Over the past few decades, the importance of sleep has become increasingly recognized for many physiologic functions, including cognition. Many studies have reported the deleterious effect of sleep loss or sleep disruption on cognitive performance. Beyond ensuring adequate sleep quality and duration, discovering methods to enhance sleep to augment its restorative effects is important to improve learning in many populations, such as the military, students, age-related cognitive decline, and cognitive disorders.

Pathogenesis and research progress in leukoaraiosis

Leukoaraiosis is a common imaging marker of cerebral small vessel disease. In recent years, with the continuous advances in brain imaging technology, the detection rate of leukoaraiosis is higher and its clinical subtypes are gradually gaining attention. Although leukoaraiosis has long been considered an incidental finding with no therapeutic necessity, there is now growing evidence linking it to, among other things, cognitive impairment and a high risk of death after stroke. Due to different research methods, some of the findings are inconsistent and even contradictory. Therefore, a comprehensive and in-depth study of risk factors for leukoaraiosis is of great clinical significance. In this review, we summarize the literature on leukoaraiosis in recent years with the aim of elucidating the disease in terms of various aspects (including pathogenesis, imaging features, and clinical features, etc.).

Transcranial Electromagnetic Treatment Stops Alzheimer’s Disease Cognitive Decline over a 2½-Year Period: A Pilot Study

Background: There is currently no therapeutic that can stop or reverse the progressive memory impairment of Alzheimer’s disease (AD). However, we recently published that 2 months of daily, in-home transcranial electromagnetic treatment (TEMT) reversed the cognitive impairment in eight mild/moderate AD subjects. These cognitive enhancements were accompanied by predicted changes in AD markers within both the blood and cerebrospinal fluid (CSF). Methods: In view of these encouraging findings, the initial clinical study was extended twice to encompass a period of 2½ years. The present study reports on the resulting long-term safety, cognitive assessments, and AD marker evaluations from the five subjects who received long-term treatment. Results: TEMT administration was completely safe over the 2½-year period, with no deleterious side effects. In six cognitive/functional tasks (including the ADAS-cog13, Rey AVLT, MMSE, and ADL), no decline in any measure occurred over this 2½-year period. Long-term TEMT induced reductions in the CSF levels of C-reactive protein, p-tau217, Aβ1-40, and Aβ1-42 while modulating CSF oligomeric Aβ levels. In the plasma, long-term TEMT modulated/rebalanced levels of both p-tau217 and total tau. Conclusions: Although only a limited number of AD patients were involved in this study, the results suggest that TEMT can stop the cognitive decline of AD over a period of at least 2½ years and can do so with no safety issues.

Transcranial Magnetic Stimulation in the Treatment of Neurological Diseases

Transcranial Magnetic Stimulation (TMS) has widespread use in research and clinical application. For psychiatric applications, such as depression or OCD, repetitive TMS protocols (rTMS) are an established and globally applied treatment option. While promising, rTMS is not yet as common in treating neurological diseases, except for neurorehabilitation after (motor) stroke and neuropathic pain treatment. This may soon change. New clinical studies testing the potential of rTMS in various other neurological conditions appear at a rapid pace. This can prove challenging for both practitioners and clinical researchers. Although most of these neurological applications have not yet received the same level of scientific/empirical scrutiny as motor stroke and neuropathic pain, the results are encouraging, opening new doors for TMS in neurology. We here review the latest clinical evidence for rTMS in pioneering neurological applications including movement disorders, Alzheimer's disease/mild cognitive impairment, epilepsy, multiple sclerosis, and disorders of consciousness.

Mechanisms for Cognitive Impairment in Epilepsy: Moving Beyond Seizures

There has been a major emphasis on defining the role of seizures in the causation of cognitive impairments like memory deficits in epilepsy. Here we focus on an alternative hypothesis behind these deficits, emphasizing the mechanisms of information processing underlying healthy cognition characterized as rate, temporal and population coding. We discuss the role of the underlying etiology of epilepsy in altering neural networks thereby leading to both the propensity for seizures and the associated cognitive impairments. In addition, we address potential treatments that can recover the network function in the context of a diseased brain, thereby improving both seizure and cognitive outcomes simultaneously. This review shows the importance of moving beyond seizures and approaching the deficits from a system-level perspective with the guidance of network neuroscience.

Effects of multisite anodal transcranial direct current stimulation combined with cognitive stimulation in patients with Alzheimer's disease and its neurophysiological correlates: A double-blind randomized clinical trial

OBJECTIVES

We aimed to examine the effects of multisite anodal transcranial direct current stimulation (tDCS) combined with cognitive stimulation (CS) over 2 months on cognitive performance and brain activity, and the relationship between them, in patients with Alzheimer's disease (AD).

METHODS

Patients with AD were randomly assigned to an active tDCS+CS (n=18) or a sham tDCS+CS (n=18) group. Cognitive performance was assessed using the Alzheimer Disease Assessment Scale-cognitive subscale (ADAS-cog) and brain activity using EEG (spectral power and coherence analysis) before and after the intervention. Multisite anodal tDCS (2 mA, 30 min) was applied over six brain regions [left and right dorsolateral prefrontal cortex (F3 and F4), Broca's area (F5), Wernicke's area (CP5), left and right somatosensory association cortex (P3 and P4)] for 24 sessions (three times a week). Both groups performed CS during tDCS.

RESULTS

Anodal tDCS+CS delays cognitive decline (ADAS-cog change) to a greater extent than sham tDCS+CS (-3.4±1.1 vs. -1.7±0.4; p=.03). Bilateral EEG coherence at high and low frequencies was greater for the active tDCS+CS than sham+CS group for most electrode pairs assessed (p < .05). The post-intervention ADAS-cog change score was predictive for EEG coherence at different sites (R²=.59 to .68; p < .05) in the active but not in the sham tDCS+CS group.

CONCLUSION

Anodal tDCS+CS improved overall cognitive function and changed EEG brain activity compared to sham tDCS+CS. Changes in cognitive performance were associated with changes in EEG measures of brain activity. Anodal tDCS+CS appears to be a promising therapeutic strategy to modulate cortical activity and improve cognitive function in patients with AD.

The Efficacy of High- or Low-Frequency Transcranial Magnetic Stimulation in Alzheimer's Disease Patients with Behavioral and Psychological Symptoms of Dementia

INTRODUCTION

Alzheimer's disease (AD) is usually accompanied by different degrees of behavioral and psychological symptoms of dementia (BPSD). Transcranial magnetic stimulation (TMS) has been applied for the treatment of AD as a painless and noninvasive therapy. However, the efficacy of repetitive TMS (rTMS) with different frequencies in AD with BPSD remains unknown.

METHODS

A total of 32 AD patients with psychobehavioral symptoms were selected as the study subjects. Among them, 16 patients were included in the high-frequency TMS group with an average disease duration of 6.22 ± 2.55 years. The low-frequency TMS group was gender and age matched with a disease course of 7.02 ± 3.33-year average duration. The high-frequency TMS group received TMS treatment twice per day for 4 weeks under 80% MT stimulation intensity, 10-Hz frequency for 0.5 h each time, and the low-frequency TMS group received TMS treatment of 2-Hz frequency for 0.5 h each time. Neuropsychological status was assessed by the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD) score. The behavioral ability was assessed by the Abilities of Daily Living (ADL) scale; cognitive function was evaluated by Mini-Mental State Examination (MMSE). The levels of β amyloid 40 and 42 (Aβ40 and Aβ42) in plasma were detected using a double-antibody sandwich enzyme-linked immunosorbent assay. All patients underwent brain magnetic resonance imaging (MRI) before and after the experiment.

RESULTS

After 2 weeks of treatment, the BEHAVE-AD and ADL scores of the patients in the high-frequency group were significantly lower than those before the treatment, and they continued to decrease after 4 weeks of treatment. The BEHAVE-AD and ADL scores of the low-frequency TMS group were also significantly lower than before treatment. The comparison between groups at different time points showed that the BEHAVE-AD and ADL scores of the patients in the high-frequency group were significantly lower than those of the patients in the low-frequency TMS group. The MMSE of high-frequency TMS-treated patients increased from 14.22 ± 3.55 before treatment to 14.67 ± 2.22 at 2 week's treatment and 17.33 ± 3.11 at 4 week's treatment (p < 0.01) in contrast to 14.19 ± 3.47, 14.28 ± 3.41, and 14.49 ± 2.79, respectively, found in the low-frequency TMS group. At week 4, the high-frequency TMS-treated group's plasma Aβ40 did not change compared to that before treatment. No effects on plasma Aβ42 were observed between the high- vs. low-frequency TMS groups. The incidence of adverse reactions during treatment was comparable between groups.

CONCLUSION

These results indicate that high-frequency TMS has the advantages of fast results, good efficacy, and high safety for the treatment of psychobehavioral abnormalities in AD patients. In addition, our study suggests that high-frequency TMS intervention can further improve the cognitive function of AD patients.

Accelerated intermittent theta-burst stimulation broadly ameliorates symptoms and cognition in Alzheimer's disease: A randomized controlled trial

BACKGROUND

Deficits in associative memory (AM) are the earliest and most prominent feature of Alzheimer's disease (AD) and demonstrate a clear cause of distress for patients and their families.

OBJECTIVE

The present study aimed to determine AM enhancements following accelerated intermittent theta-burst stimulation (iTBS) in patients with AD.

METHODS

In a randomized, double-blind, sham-controlled design, iTBS was administered to the left dorsolateral prefrontal cortex (DLPFC) of patients with AD for 14 days. Measurements included AM (primary outcome) and a comprehensive neuropsychological battery. Patients were evaluated at baseline, following the intervention (week 2), and 8 weeks after treatment cessation (week 10).

RESULTS

Sixty patients with AD were initially enrolled; 47 completed the trial. The active group displayed greater AM improvements compared with the sham group at week 2 (P = 0.003), which was sustained at week 10. Furthermore, higher Mini-Mental State Examination (MMSE) scores at baseline were associated with greater AM improvements at weeks 2 and 10. For the independent iTBS group, this correlation predicted improvements in AM (P < 0.001) and identified treatment responders with 92% accuracy. Most of the neuropsychological tests were markedly improved in the active group. In particular, the Montreal Cognitive Assessment and MMSE in the active group increased by 2.8 and 2.3 points, respectively, at week 2, while there was no marked change in the sham group.

CONCLUSION

In the present study, accelerated iTBS of the DLPFC demonstrated an effective and well-tolerated complementary treatment for patients with AD, especially for individuals with relatively high MMSE scores.

Brain stimulation: a therapeutic approach for the treatment of neurological disorders

Brain stimulation has become one of the most acceptable therapeutic approaches in recent years and a powerful tool in the remedy against neurological diseases. Brain stimulation is achieved through the application of electric currents using non-invasive as well as invasive techniques. Recent technological advancements have evolved into the development of precise devices with capacity to produce well-controlled and effective brain stimulation. Currently, most used non-invasive techniques are repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), whereas the most common invasive technique is deep brain stimulation (DBS). In last decade, application of these brain stimulation techniques has not only exploded but also expanded to wide variety of neurological disorders. Therefore, in the current review, we will provide an overview of the potential of both non-invasive (rTMS and tDCS) and invasive (DBS) brain stimulation techniques in the treatment of such brain diseases.

Transcranial Magnetic Stimulation and Working Memory Training to Address Language Impairments in Aphasia: A Case Study

BACKGROUND

Traditionally, people with aphasia (PWA) are treated with impairment-based language therapy to improve receptive and expressive language skills. In addition to language deficits, PWA are often affected by some level of working memory (WM) impairments. Both language and working memory impairments combined have a negative impact on PWA's quality of life. The aim of this study was to investigate whether the application of intermittent theta-burst stimulation (iTBS) combined with computerized WM training will result in near-ransfer effects (i.e., trained WM) and far-transfer effects (i.e., untrained language tasks) and have a positive effect on the quality of life of PWA.

METHODS

The participant was a 63-year-old Greek-Cypriot male who presented with mild receptive aphasia and short-term memory difficulties. Treatment was carried out using a multiple baseline (MB) design composed of a pretherapy or baseline testing phase, a therapy phase, and a posttherapy/follow-up phase. The treatment program involved iTBS application to the left dorsolateral prefrontal cortex (DLPFC), an area responsible for WM, for 10 consecutive sessions. The participant received a 3-minute iTBS application followed by 30-minute computer-assisted WM training. Outcome measures included a WM screening test, a standardized aphasia test, a nonverbal intelligence test, story-telling speech samples, a procedural discourse task, and a questionnaire addressing quality of life. These measures were performed three times before the treatment, immediately upon completion of the treatment, and once during follow-up testing at 3 months posttreatment.

RESULTS

We found a beneficial effect of iTBS and WM training on naming, reading, WM, reasoning, narrative, communication efficiency, and quality of life (QoL). Implications for Rehabilitation. Noninvasive brain stimulation combined with computerized WM training may be used in aphasia rehabilitation to improve WM and generalize to language improvement.

Diagnostic contribution and therapeutic perspectives of transcranial magnetic stimulation in dementia

Transcranial magnetic stimulation (TMS) is a powerful tool to probe in vivo brain circuits, as it allows to assess several cortical properties such asexcitability, plasticity and connectivity in humans. In the last 20 years, TMS has been applied to patients with dementia, enabling the identification of potential markers of thepathophysiology and predictors of cognitive decline; moreover, applied repetitively, TMS holds promise as a potential therapeutic intervention. The objective of this paper is to present a comprehensive review of studies that have employed TMS in dementia and to discuss potential clinical applications, from the diagnosis to the treatment. To provide a technical and theoretical framework, we first present an overview of the basic physiological mechanisms of the application of TMS to assess cortical excitability, excitation and inhibition balance, mechanisms of plasticity and cortico-cortical connectivity in the human brain. We then review the insights gained by TMS techniques into the pathophysiology and predictors of progression and response to treatment in dementias, including Alzheimer's disease (AD)-related dementias and secondary dementias. We show that while a single TMS measure offers low specificity, the use of a panel of measures and/or neurophysiological index can support the clinical diagnosis and predict progression. In the last part of the article, we discuss the therapeutic uses of TMS. So far, only repetitive TMS (rTMS) over the left dorsolateral prefrontal cortex and multisite rTMS associated with cognitive training have been shown to be, respectively, possibly (Level C of evidence) and probably (Level B of evidence) effective to improve cognition, apathy, memory, and language in AD patients, especially at a mild/early stage of the disease. The clinical use of this type of treatment warrants the combination of brain imaging techniques and/or electrophysiological tools to elucidate neurobiological effects of neurostimulation and to optimally tailor rTMS treatment protocols in individual patients or specific patient subgroups with dementia or mild cognitive impairment.

Neuromodulation in the Treatment of Alzheimer's Disease: Current and Emerging Approaches

Neuromodulation as a treatment strategy for psychiatric and neurological diseases has grown in popularity in recent years, with the approval of repetitive transcranial magnetic stimulation (rTMS) for the treatment of depression being one such example. These approaches offer new hope in the treatment of diseases that have proven largely intractable to traditional pharmacological approaches. For this reason, neuromodulation is increasingly being explored for the treatment of Alzheimer's disease. However, such approaches have variable, and, in many cases, very limited evidence for safety and efficacy, with most human evidence obtained in small clinical trials. Here we review work in animal models and humans with Alzheimer's disease exploring emerging neuromodulation modalities. Approaches reviewed include deep brain stimulation, transcranial magnetic stimulation, transcranial electrical stimulation, ultrasound stimulation, photobiomodulation, and visual or auditory stimulation. In doing so, we clarify the current evidence for these approaches in treating Alzheimer's disease and identify specific areas where additional work is needed to facilitate their clinical translation.

Cognitive Enhancement of Repetitive Transcranial Magnetic Stimulation in Patients With Mild Cognitive Impairment and Early Alzheimer's Disease: A Systematic Review and Meta-Analysis

Repetitive transcranial magnetic stimulation (rTMS), a non-invasive brain stimulation technique, has been considered as a potentially effective treatment for the cognitive impairment in patients with mild cognitive impairment (MCI) and Alzheimer’s Disease (AD). However, the effectiveness of this therapy is still under debate due to the variety of rTMS parameters and individual differences including distinctive stages of AD in the previous studies. The current meta-analysis is aiming to assess the cognitive enhancement of rTMS treatment on patients of MCI and early AD. Three datasets (PubMed, Web of Science and CKNI) were searched with relative terms and finally twelve studies with 438 participants (231 in the rTMS group and 207 in the control group) in thirteen randomized, double-blind and controlled trials were included. Random effects analysis revealed that rTMS stimulation significantly introduced cognitive benefits in patients of MCI and early AD compared with the control group (mean effect size, 1.17; 95% CI, 0.76 - 1.57). Most settings of rTMS parameters (frequency, session number, stimulation site number) significantly enhanced global cognitive function, and the results revealed that protocols with 10 Hz repetition frequency and DLPFC as the stimulation site for 20 sessions can already be able to produce cognitive improvement. The cognitive enhancement of rTMS could last for one month after the end of treatment and patients with MCI were likely to benefit more from the rTMS stimulation. Our meta-analysis added important evidence to the cognitive enhancement of rTMS in patients with MCI and early AD and discussed potential underlying mechanisms about the effect induced by rTMS.

Repetitive Transcranial Magnetic Stimulation in the Treatment of Alzheimer's Disease and Other Dementias

Dementia is a debilitating impairment of cognitive functions that affects millions of people worldwide. There are several diseases belonging to the dementia spectrum, most prominently Alzheimer’s disease (AD), vascular dementia (VD), Lewy body dementia (LBD) and frontotemporal dementia (FTD). Repetitive transcranial magnetic stimulation (rTMS) is a safe, non-invasive form of brain stimulation that utilizes a magnetic coil to generate an electrical field and induce numerous changes in the brain. It is considered efficacious for the treatment of various neuropsychiatric disorders. In this paper, we review the available studies involving rTMS in the treatment of these dementia types. The majority of studies have involved AD and shown beneficial effects, either as a standalone, or as an add-on to standard-of-care pharmacological treatment and cognitive training. The dorsolateral prefrontal cortex seems to hold a central position in the applied protocols, but several parameters still need to be defined. In addition, rTMS has shown potential in mild cognitive impairment as well. Regarding the remaining dementias, research is still at preliminary phases, and large, randomized studies are currently lacking.

Functional Imaging to Guide Network-Based TMS Treatments: Toward a Tailored Medicine Approach in Alzheimer's Disease

A growing number of studies is using fMRI-based connectivity to guide transcranial magnetic stimulation (TMS) target identification in both normal and clinical populations. TMS has gained increasing attention as a potential therapeutic strategy also in Alzheimer's disease (AD), but an endorsed target localization strategy in this population is still lacking. In this proof of concept study, we prove the feasibility of a tailored TMS targeting approach for AD, which stems from a network-based perspective. Based on functional imaging, the procedure allows to extract individual optimal targets meanwhile accounting for functional variability. Single-subject resting-state fMRI was used to extract individual target coordinates of two networks primarily affected in AD, the default mode and the fronto-parietal network. The localization of these targets was compared to that of traditional group-level approaches and tested against varying degrees of TMS focality. The distance between individual fMRI-derived coordinates and traditionally defined targets was significant for a supposed TMS focality of 12 mm and in some cases up to 20 mm. Comparison with anatomical labels confirmed a lack of 1:1 correspondence between anatomical and functional targets. The proposed network-based fMRI-guided TMS approach, while accounting for inter-individual functional variability, allows to target core AD networks, and might thus represent a step toward tailored TMS interventions for AD.

Protective effects of repetitive transcranial magnetic stimulation against 6-OHDA-induced Parkinson's symptoms in a mice model: the key role of miR-409-3p/PDHB axis

AIM

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive technique showing improvement effects on Parkinson's disease (PD). Multiple microRNAs (miRs) are dys-expressed during the progression of PD. In the current study, the potential involvement of miRs in the anti-PD effects of rTMS was explored.

METHODS

PD symptoms were induced in mice with 6-OHDA. The expression profile of miRs influenced by rTMS in PD mice was detected by microarray technique and validated by RT-qPCR detection. The PD mice were treated with rTMS and the changes in cognitive behaviors, substantia nigra neuron number, brain histology, and Aβ_1-42 level were detected. The activity of miR-409-3p/PDHB axis was also detected to preliminarily explain the interaction between miRs and rTMS.

RESULTS

The detection of microarray showed that 266 miRs were dys-expressed in PD mice after the administration of rTMS, including 101 up-regulated ones and 146 down-regulated ones. With validation by RT-qPCR detection, miR-409-3p was selected for subsequent assays. Administrations of rTMS improved cognitive behaviors of mice, increased neuron number, and attenuated brain injuries induced by 6-OHDA. The cerebrospinal fluid (CSF) level of Aβ_1-42 was induced, while the brain level of Aβ_1-42 was suppressed by rTMS. Regarding miR-409-3p/PDHB axis, rTMS administrations suppressed miR-409-3p level and increased the expression of PDHB.

CONCLUSION

Administrations of rTMS showed considerable protective effects on brain tissues against PD-induced injuries, which was associated with the changes in miR levels. The current study demonstrated that the inhibition of miR-409-3p by rTMS contributed to the attenuation of PD by inducing PDHB.

Repetitive Transcranial Magnetic Stimulation as an Add-On Treatment for Cognitive Impairment in Alzheimer's Disease and Its Impact on Self-Rated Quality of Life and Caregiver's Burden

Alzheimer’s disease (AD) is associated with progressive memory loss and decline in executive functions, as well as neuropsychiatric symptoms. Patients usually consider quality of life (QoL) and mood as more important for their health status than disease-specific physical and mental symptoms. In this open-label uncontrolled trial, 12 subjects diagnosed with AD underwent 10 sessions of repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (10 Hz, 20 min, 2000 pulses/day, 110% MT). Outcomes were measured before and 30 days after treatment. Our primary objective was to test the efficacy of rTMS as an add-on treatment for AD on the global cognitive function, assessed through the Mini-Mental State Examination (MMSE) and the Mattis Dementia Rating Scale (MDRS). As secondary objectives, the detailed effect on cognitive functions, depression and anxiety symptoms, QoL, and functionality in daily life activities were evaluated, as well as correlations between QoL and cognition, depression and anxiety scores. The treatment significantly enhanced semantic memory and reduced anxiety. Improvement of these features in AD could become an important target for treatment strategies. Although limited by its design, this trial may contribute with another perspective on the analysis and the impact of rTMS on AD.

A Scoping Review of Cognitive Training in Neurodegenerative Diseases via Computerized and Virtual Reality Tools: What We Know So Far

Most prevalent neurodegenerative diseases such as Alzheimer's disease, frontotemporal dementia, Parkinson's disease and multiple sclerosis are heterogeneous in their clinical profiles and underlying pathophysiology, although they typically share the presence of cognitive impairment that worsens significantly during the course of the disease. Viable pharmacological options for cognitive symptoms in these clinical conditions are currently lacking. In recent years, several studies have started to apply Computerized Cognitive Training (CCT) and Virtual Reality (VR) tools to try and contrast patients' cognitive decay over time. However, no in-depth literature review of the contribution of these promising therapeutic options across main neurodegenerative diseases has been conducted yet. The present paper reports the state-of-the-art of CCT and VR studies targeting cognitive impairment in most common neurodegenerative conditions. Our twofold aim is to point out the scientific evidence available so far and to support health professionals to consider these promising therapeutic tools when planning rehabilitative interventions, especially when the access to regular and frequent hospital consultations is not easy to be provided.

Repetitive Transcranial Magnetic Stimulation With H-Coil in Alzheimer's Disease: A Double-Blind, Placebo-Controlled Pilot Study

Focal repetitive transcranial magnetic stimulation (rTMS) has been applied to improve cognition in Alzheimer's disease (AD) with conflicting results. We applied rTMS in AD in a pilot placebo-controlled study using the H2-coil. H-coils are suitable for targeting wider neuronal structures compared with standard focal coils, in particular the H2-coil stimulates simultaneously the frontal-parietal-temporal lobes bilaterally. Thirty patients (mean age 70.9 year, SD 8.1; mean MMSE score 16.9, SD 5.5) were randomized to sham or real 10 Hz rTMS stimulation with the H2-coil. Each patient underwent 3 sessions/week for 4 weeks, followed by 4 weeks with maintenance treatment (1 session/week). Primary outcome was improvement of ADAS-cog at 4 and 8 weeks compared with baseline. A trend toward an improved ADAS-cog score over time was observed for patients undergoing real rTMS, with actively treated patients experiencing a mean decrease of −1.01 points at the ADAS-Cog scale score per time point (95% CIs −0.02 to −3.13, p < 0.04). This trend was no longer evident 2 months after the end of treatment. Real rTMS showed no significant effect on MMSE and BDI changes over time. These preliminary findings suggest that rTMS with H-coil is feasible and safe in patients with probable AD and might provide beneficial, even though transient, effects on cognition. This study prompts larger studies in the early stages of AD, combining rTMS and cognitive rehabilitation.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT04562506.

Rhythmic air-puff into nasal cavity modulates activity across multiple brain areas: A non-invasive brain stimulation method to reduce ventilator-induced memory impairment

Mechanical ventilation (MV) can result in long-term brain impairments that are resistant to treatment. The mechanisms underlying MV-induced brain function impairment remain unclear. Since nasal airflow modulates brain activity, here we evaluated whether reinstating airflow during MV could influence the memory performance of rats after recovery. Rats were allocated into two study groups: one group received rhythmic air-puff into the nasal cavity during MV and a control group that underwent ventilation without air-puff. During MV, air-puffs induced time-locked event potentials in OB, mPFC and vHPC and significantly increased the oscillatory activity at the air-puff frequency. Furthermore, in mPFC and vHPC, (but not in OB), delta and theta oscillations were more prominent during air-puff application. After recovery, working memory performance was significantly higher in the air-puff group compared to control. Our study thus suggests a promising non-invasive brain stimulation approach to alleviate the neurological complications of prolonged mechanical ventilation.

Past, Present, and Future of Non-invasive Brain Stimulation Approaches to Treat Cognitive Impairment in Neurodegenerative Diseases: Time for a Comprehensive Critical Review

Low birth rates and increasing life expectancy experienced by developed societies have placed an unprecedented pressure on governments and the health system to deal effectively with the human, social and financial burden associated to aging-related diseases. At present, ∼24 million people worldwide suffer from cognitive neurodegenerative diseases, a prevalence that doubles every five years. Pharmacological therapies and cognitive training/rehabilitation have generated temporary hope and, occasionally, proof of mild relief. Nonetheless, these approaches are yet to demonstrate a meaningful therapeutic impact and changes in prognosis. We here review evidence gathered for nearly a decade on non-invasive brain stimulation (NIBS), a less known therapeutic strategy aiming to limit cognitive decline associated with neurodegenerative conditions. Transcranial Magnetic Stimulation and Transcranial Direct Current Stimulation, two of the most popular NIBS technologies, use electrical fields generated non-invasively in the brain to long-lastingly enhance the excitability/activity of key brain regions contributing to relevant cognitive processes. The current comprehensive critical review presents proof-of-concept evidence and meaningful cognitive outcomes of NIBS in eight of the most prevalent neurodegenerative pathologies affecting cognition: Alzheimer's Disease, Parkinson's Disease, Dementia with Lewy Bodies, Primary Progressive Aphasias (PPA), behavioral variant of Frontotemporal Dementia, Corticobasal Syndrome, Progressive Supranuclear Palsy, and Posterior Cortical Atrophy. We analyzed a total of 70 internationally published studies: 33 focusing on Alzheimer's disease, 19 on PPA and 18 on the remaining neurodegenerative pathologies. The therapeutic benefit and clinical significance of NIBS remains inconclusive, in particular given the lack of a sufficient number of double-blind placebo-controlled randomized clinical trials using multiday stimulation regimes, the heterogeneity of the protocols, and adequate behavioral and neuroimaging response biomarkers, able to show lasting effects and an impact on prognosis. The field remains promising but, to make further progress, research efforts need to take in account the latest evidence of the anatomical and neurophysiological features underlying cognitive deficits in these patient populations. Moreover, as the development of in vivo biomarkers are ongoing, allowing for an early diagnosis of these neuro-cognitive conditions, one could consider a scenario in which NIBS treatment will be personalized and made part of a cognitive rehabilitation program, or useful as a potential adjunct to drug therapies since the earliest stages of suh diseases. Research should also integrate novel knowledge on the mechanisms and constraints guiding the impact of electrical and magnetic fields on cerebral tissues and brain activity, and incorporate the principles of information-based neurostimulation.

Therapeutic efficacy of repetitive transcranial magnetic stimulation in an animal model of Alzheimer's disease

Previous studies on repetitive transcranial magnetic stimulation (rTMS) suggested potential neurorestorative properties in Alzheimer's disease (AD). This study aimed to investigate therapeutic effects of rTMS on an AD mouse model at high and low frequencies. The subject mice were allocated into the AD model group (AD induced by intracerebroventricular amyloid beta 42 oligomer [Aβ42] injection) and the saline-injected control group. Each group was subdivided according to rTMS treatment: high frequency (20 Hz), low frequency (1 Hz), and not rTMS-treated. Behavioural assessments with Y-maze test and novel object recognition task were performed; the results indicated cognition recovery by both the frequencies of rTMS after treatment in the AD model (Ps < 0.01). Tendency of further effects by high frequency compared to low frequency rTMS was also shown in Y-maze test. Neurotransmitter assay showed increment in dopamine concentration and upregulation of dopamine-receptor 4 (DR4) by rTMS in AD mice with higher response by high frequency stimulation (Ps < 0.05). Only high-frequency rTMS induced an elevation of brain-derived neurotrophic factor (BDNF) levels and enhanced the expression of Nestin and NeuN in the brain tissue (Ps < 0.05). Under in vitro conditions, Aβ42 incubated mouse hippocampal cell showed an increase in dopamine levels and BDNF by application of high-frequency rTMS treatment. In conclusion, rTMS might have a potential therapeutic effect on AD, and it seems to be related with dopaminergic activation. High frequency of stimulation seems to induce higher efficacy than that induced by low frequency, with elevated expressions of DR4 gene and neurogenic proteins.