A case report of daily left prefrontal repetitive transcranial magnetic stimulation (rTMS) as an adjunctive treatment for Alzheimer disease

Facilitated lexical processing accuracy and reaction times following repetitive Transcranial Magnetic Stimulation in dementia of the Alzheimer type: a case study

We investigated the potential effects of high-frequency (10 Hz) repetitive Transcranial Magnetic Stimulation (rTMS) of the bilateral Dorsolateral Prefrontal Cortex (DLPFC) (30-sessions; 2-sessions/day) on improving lexical processing in one participant with mild - Alzheimer's disease (hereafter dementia of the Alzheimer type-DAT). Increased accuracy and faster reaction times (RTs) were reported in a lexical-decision task (LDT) up to 2-months post-intervention. The current findings indicate that high-frequency stimulation of the DLPFC might be a potential therapeutic tool to improve lexical processing in mild-DAT.

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.

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.

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.

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.

Precision Repetitive Transcranial Magnetic Stimulation Over the Left Parietal Cortex Improves Memory in Alzheimer's Disease: A Randomized, Double-Blind, Sham-Controlled Study

Objective

We aim to study the effect of precision repetitive transcranial magnetic stimulation (rTMS) over the left parietal cortex on the memory and cognitive function in Alzheimer’s disease (AD).

Methods

Based on the resting-state functional magnetic resonance imaging, the left parietal cortex site with the highest functional connectivity to the hippocampus was selected as the target of rTMS treatment. Sixty-nine AD patients were randomized to either rTMS or sham treatment (five sessions/week for a total of 10 sessions). The Mini-Mental State Examination (MMSE), 12-Word Philadelphia Verbal Learning Test (PVLT), and Clinical Dementia Rating (CDR) were assessed at baseline and after the last session.

Results

After a 2-week treatment, compared to patients in the sham group, those in the rTMS group scored significantly higher on PVLT total score and its immediate recall subscale score. Moreover, in the rTMS group, there were significant improvements after the 2-week treatment, which were manifested in MMSE total score and its time orientation and recall subscale scores, as well as PVLT total score and its immediate recall and short delay recall subscale scores. In the sham group, the PVLT total score was significantly improved.

Conclusion

The target site of the left parietal cortex can improve AD patients’ cognitive function, especially memory, providing a potential therapy.

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.

Low-Frequency Repetitive Transcranial Magnetic Stimulation of the Right Dorsolateral Prefrontal Cortex Enhances Recognition Memory in Alzheimer's Disease

BACKGROUND

The lack of effective pharmacological or behavioral interventions for memory impairments associated with Alzheimer's disease (AD) emphasizes the need for the investigation of approaches based on neuromodulation.

OBJECTIVE

This study examined the effects of inhibitory repetitive transcranial magnetic stimulation (rTMS) of prefrontal cortex on recognition memory in AD patients.

METHODS

In a first experiment, 24 mild AD patients received sham and real 1Hz rTMS over the left and right dorsolateral prefrontal cortex (DLPFC), in different sessions, between encoding and retrieval phases of a non-verbal recognition memory task. In a second experiment, another group of 14 AD patients underwent sham controlled repeated sessions of 1Hz rTMS of the right DLPFC across a two week treatment. Non-verbal recognition memory task was performed at baseline, at the end of the two weeks period and at a follow up of 1 month.

RESULTS

Right real rTMS significantly improved memory performance compared to right sham rTMS (p = 0.001). Left real rTMS left the memory performance unchanged as compared with left sham rTMS (p = 0.46). The two sham conditions did not differ between each other (p = 0.24). In the second experiment, AD patients treated with real rTMS showed an improvement of memory performance at the end of the two weeks treatment (p = 0.0009), that persisted at 1-month follow-up (p = 0.002).

CONCLUSION

These findings provide evidence that inhibitory rTMS over the right DLPFC can improve recognition memory function in AD patients. They also suggest the importance of a new approach of non-invasive brain stimulation as a promising treatment in AD.

Enhancing cognitive training effects in Alzheimer's disease: rTMS as an add-on treatment

The treatment of Alzheimer's disease (AD) in the field of non-pharmacological interventions is a challenging issue, given the limited benefits of the available drugs. Cognitive training (CT) represents a commonly recommended strategy in AD. Recently, repetitive transcranial magnetic stimulation (rTMS) has gained increasing attention as a promising therapeutic tool for the treatment of AD, given its ability of enhancing neuroplasticity. In the present randomized, double-blind, sham-controlled study, we aimed at investigating the add-on effect of a high frequency rTMS protocol applied over the left dorsolateral prefrontal cortex (DLPFC) combined with a face-name associative memory CT in the continuum of AD pathology. Fifty patients from a very early to a moderate phase of dementia were randomly assigned to one of two groups: CT plus real rTMS or CT plus placebo rTMS. The results showed that the improvement in the trained associative memory induced with rTMS was superior to that obtained with CT alone. Interestingly, the extent of the additional improvement was affected by disease severity and levels of education, with less impaired and more educated patients showing a greater benefit. When testing for generalization to non-trained cognitive functions, results indicated that patients in CT-real group showed also a greater improvement in visuospatial reasoning than those in the CT-sham group. Interestingly, this improvement persisted over 12 weeks after treatment beginning. The present study provides important hints on the promising therapeutic use of rTMS in AD.

Corticomotor Plasticity Predicts Clinical Efficacy of Combined Neuromodulation and Cognitive Training in Alzheimer's Disease

OBJECTIVE

To investigate the efficacy of repetitive transcranial magnetic stimulation (rTMS) combined with cognitive training for treatment of cognitive symptoms in patients with Alzheimer's disease (AD). A secondary objective was to analyze associations between brain plasticity and cognitive effects of treatment.

METHODS

In this randomized, sham-controlled, multicenter clinical trial, 34 patients with AD were assigned to three experimental groups receiving 30 daily sessions of combinatory intervention. Participants in the real/real group (n = 16) received 10 Hz repetitive transcranial magnetic stimulation (rTMS) delivered separately to each of six cortical regions, interleaved with computerized cognitive training. Participants in the sham rTMS group (n = 18) received sham rTMS combined with either real (sham/real group, n = 10) or sham (sham/sham group, n = 8) cognitive training. Effects of treatment on neuropsychological (primary outcome) and neurophysiological function were compared between the 3 treatment groups. These, as well as imaging measures of brain atrophy, were compared at baseline to 14 healthy controls (HC).

RESULTS

At baseline, patients with AD had worse cognition, cerebral atrophy, and TMS measures of cortico-motor reactivity, excitability, and plasticity than HC. The real/real group showed significant cognitive improvement compared to the sham/sham, but not the real/sham group. TMS-induced plasticity at baseline was predictive of post-intervention changes in cognition, and was modified across treatment, in association with changes of cognition.

INTERPRETATION

Combined rTMS and cognitive training may improve the cognitive status of AD patients, with TMS-induced cortical plasticity at baseline serving as predictor of therapeutic outcome for this intervention, and potential mechanism of action.

CLINICAL TRIAL REGISTRATION

www.ClinicalTrials.gov, identifier NCT01504958.

Non-invasive Brain Stimulation in Alzheimer's Disease and Mild Cognitive Impairment-A State-of-the-Art Review on Methodological Characteristics and Stimulation Parameters

Background: Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have been proposed as a new therapeutic way to enhance the cognition of patients with dementia. However, serious methodological limitations appear to affect the estimates of their efficacy. We reviewed the stimulation parameters and methods of studies that used TMS or tDCS to alleviate the cognitive symptoms of patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). Moreover, we evaluated the risk of bias in these studies. Our aim was to highlight the current vulnerabilities of the field and to formulate recommendations on how to manage these issues when designing studies. Methods: Electronic databases and citation searching were used to identify studies administering TMS or tDCS on patients with AD or MCI to enhance cognitive function. Data were extracted by one review author into summary tables with the supervision of the authors. The risk of bias analysis of randomized-controlled trials was conducted by two independent assessors with version 2 of the Cochrane risk-of-bias tool for randomized trials. Results: Overall, 36 trials were identified of which 23 randomized-controlled trials underwent a risk of bias assessment. More than 75% of randomized-controlled trials involved some levels of bias in at least one domain. Stimulation parameters were highly variable with some ranges of effectiveness emerging. Studies with low risk of bias indicated TMS to be potentially effective for patients with AD or MCI while questioned the efficacy of tDCS. Conclusions: The presence and extent of methodical issues affecting TMS and tDCS research involving patients with AD and MCI were examined for the first time. The risk of bias frequently affected the domains of the randomization process and selection of the reported data while missing outcome was rare. Unclear reporting was present involving randomization, allocation concealment, and blinding. Methodological awareness can potentially reduce the high variability of the estimates regarding the effectiveness of TMS and tDCS. Studies with low risk of bias delineate a range within TMS parameters seem to be effective but question the efficacy of tDCS.

The use of repetitive transcranial magnetic stimulation (rTMS) following traumatic brain injury (TBI): A scoping review

There is continued interest in developing effective and innovative treatment approaches to manage and improve outcomes after traumatic brain injury (TBI). Included in this, is the potential use of repetitive transcranial magnetic stimulation (rTMS), a neuromodulatory tool currently recommended by the National Institute for Health and Care Excellence as a treatment for depression. This review considers the application of rTMS after TBI, focussing on its therapeutic efficacy for a broad range of sequalae, whether an optimal and safe rTMS protocol can be determined, and recommendations for future clinical and research work. Five research databases (MEDLINE, CINAHL, PsychINFO, SCOPUS, and Web of Science) were electronically searched, identifying 30 empirical studies (single and multiple subject case reports; randomized controlled trials) for the full review. Evidence suggests that rTMS has the potential to be an efficacious therapeutic intervention for multiple symptoms after TBI, including depression, dizziness, central pain, and visual neglect. However, the picture is less encouraging for prolonged disorders of consciousness and mixed for cognitive outcomes. Overall, rTMS was well-tolerated by patients, although some incidents of side effects and seizures have been reported. Recommendations are made for more comprehensive guidelines and sufficient reporting of rTMS parameters and procedures.

Deep Transcranial Magnetic Stimulation for the Treatment of Negative Symptoms in Schizophrenia: Beyond an Antidepressant Effect

BACKGROUND

Negative symptoms of schizophrenia show limited response to both typical and atypical antipsychotics. Repetitive transcranial magnetic stimulation applied over the prefrontal cortex (PFC) has been proposed as an adjuvant to pharmacological treatment of negative symptoms in schizophrenia, but whether the improvements obtained are specific to negative symptoms or attributable to antidepressant effects is still unclear.

OBJECTIVE

The aim of the present study is to determine to which extent the improvements in negative symptoms of schizophrenia obtained after high-frequency stimulation of the bilateral PFC using deep TMS (dTMS) are attributable to antidepressant effects.

METHODS

Repetitive dTMS was administered to the PFC in a cohort of 16 patients with schizophrenia under successful pharmacological control of positive symptoms and predominant negative symptoms. Patients were treated using high-frequency (18 Hz) bilateral stimulation applied over the lateral PFC bilaterally using Brainsway H-2 coil. The effects of dTMS on negative symptoms were measured using the Scale for the Assessment of Negative Symptoms and the Positive and Negative Syndrome Scales. We then compared the improvements in negative symptoms obtained in patients showing depressive symptoms (≥7 points) with those found in patients without depression (>7 points), as determined by the Calgary Scale for Depression.

RESULTS

Repetitive dTMS treatment induced significant improvements in negative symptoms as assessed using both Scale for the Assessment of Negative Symptoms and Positive and Negative Syndrome Scales. Comparison of the improvements obtained in patients with or without depression at the beginning of treatment revealed similar improvements in negative symptoms, irrespective of subjacent depression.

CONCLUSIONS

Our data suggest that the beneficial effects of high frequency dTMS of the PFC cannot be attributed solely to its antidepressant effects.

The Dynamic Duo: Combining noninvasive brain stimulation with cognitive interventions

Pharmacotherapy, psychotherapy, and non-invasive brain stimulation (NIBS)¹ each show efficacy in the treatment of psychiatric disorders; however, more efficacious interventions are needed as reflected by an overall unmet need in mental health care. While each modality has typically been studied and developed as a monotherapy, in practice they are typically used in combination. Research has begun to emerge studying the potential synergistic actions of multi-modal, combination therapies. For example, NIBS combined with rehabilitation strategies have demonstrated some success for speech and motor rehabilitation in stroke patients. In this review we present evidence suggesting that combining NIBS with targeted, cognitive interventions offers a potentially powerful new approach to treating neuropsychiatric disorders. Here we focus on NIBS studies using transcranial direct current stimulation (tDCS)² and transcranial magnetic stimulation (TMS)³ given that these modalities are relatively safe, noninvasive, and can be performed simultaneously with neurocognitive interventions. We review the concept of "state dependent" effects of NIBS and highlight how simultaneous or sequential cognitive interventions could help optimize NIBS therapy by providing further control of ongoing neural activity in targeted neural networks. This review spans a range of neuropsychiatric disorders including major depressive disorder, schizophrenia, generalized anxiety, and autism. For each disorder, we emphasize neuroanatomical circuitry that could be engaged with combination therapy and critically discuss the literature that has begun to emerge. Finally, we present possible underlying mechanisms and propose future research strategies that may further refine the potential of combination therapies.

The role of repetitive transcranial magnetic stimulation (rTMS) in the treatment of cognitive impairment in patients with Alzheimer's disease: A systematic review and meta-analysis

BACKGROUND

Although repetitive transcranial magnetic stimulation (rTMS) has been considered a potentially effective treatment for cognitive impairment in patients with Alzheimer's disease (AD), previous studies have produced inconsistent results. The objective of this meta-analysis was to evaluate the effects of rTMS on cognitive function in patients with AD.

METHODS

PubMed, EMBASE, Web of Science, MEDLINE and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for relevant terms. Abstracts of all papers were carefully reviewed, followed by data extraction, quality assessment, data synthesis and subgroup analyses.

RESULT

A total of 12 studies with 231 patients were included, with 8 randomized controlled studies and 4 self-controlled studies. Eleven studies used high frequency rTMS (≥ 5 Hz), but only one study directly compared the difference between low-frequency (1 Hz) and high-frequency (20 Hz). Random-effects analysis revealed that rTMS could significantly improve cognition compared with sham-rTMS (SMD: 0.60, 95% CI: 0.35-0.85, P < .0001). In subgroup analyses, the effect for stimulation at a single target was 0.13 (95% CI: -0.35-0.62) and multiple targets 0.86 (95% CI: 0.18-1.54). Treatment for ≤3 sessions produced an effect of 0.29 (95% CI: -1.04-1.62), whereas treatment for ≥5 sessions produced an effect of 2.77 (95% CI: 2.22-3.32). No differences were found for rTMS combined with medication or cognitive training.

CONCLUSIONS

rTMS can significantly improve cognitive ability in patients with mild to moderate AD. Stimulation of multiple sites and long-term treatment are better at improving AD-associated cognitive performance. Furthermore, some novel interventional targets, like precuneus (PC), may be a more effective therapeutic site to improve memory in AD.

Transcranial magnetic stimulation intervention in Alzheimer's disease: a research proposal for a randomized controlled trial

Objective

Alzheimer’s disease is a major health problem in our society. To date, pharmacological treatments have obtained poor results and there is a growing interest in finding non-pharmacological interventions for this disease. Transcranial magnetic stimulation (TMS) is a non-invasive technique that is able to induce changes in brain activity and long-term modifications in impaired neural networks, becoming a promising clinical intervention. Our goal is to study the benefit of individualized TMS targeting based on the patient’s functional connectivity (personalized targeting), and short duration TMS protocol, instead of current non-individualized and longer session approaches. A double blind randomized controlled trial will be conducted to assess the effects of TMS treatment immediately, 1 month, 3 months and 6 months after the end of the intervention. Fifty-four patients with a diagnosis of Alzheimer’s disease will be randomly allocated into experimental (active TMS), sham control, or conventional intervention control group. We will quantify changes in cognitive, functional, and emotional deficits in Alzheimer patients, as well as the functional connectivity changes induced by the TMS treatment.

Results

We expect to demonstrate that personalized TMS intervention has a measurable positive impact in cognition, emotion, daily living activities and brain connectivity, thus representing a potential treatment for Alzheimer’s disease.

Trial registration The trial has been prospectively registered at ClinicalTrials.gov, identifier NCT03121066. Date of registration: 04/19/2017

Effects of repetitive transcranial magnetic stimulation on improvement of cognition in elderly patients with cognitive impairment: a systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to examine the effects of repetitive transcranial magnetic stimulation (rTMS) on cognitive function in older patients with cognitive impairment.

METHODS

A literature search was performed for articles published in English using the 10 databases (MEDLINE, EMBASE, PsycINFO, INSPEC, the Cumulative Index to Nursing and Allied Health Literature Plus, AMED, Biological Sciences, ClinicalTrials.gov, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews) from their inception to May 2016. The primary outcome was cognitive function as measured by the Mini-Mental State Examination or the Alzheimer's Disease Assessment Scale-cognitive subscale.

RESULTS

Seven RCTs were included in the meta-analysis, with a sample of 107 active and 87 sham rTMS. Active rTMS was found to be more effective in improving cognition (Hedges' g = 0.48; 95% confidence interval 0.12 to 0.84).

CONCLUSIONS

High-frequency rTMS showed a benefit on cognition amongst older patients with mild to moderate Alzheimer's disease. rTMS was shown to have great potential as a safe and well-tolerated alternative intervention for cognition. Copyright © 2017 John Wiley & Sons, Ltd.

Brain Stimulation in Alzheimer's Disease

Brain stimulation techniques can modulate cognitive functions in many neuropsychiatric diseases. Pilot studies have shown promising effects of brain stimulations on Alzheimer's disease (AD). Brain stimulations can be categorized into non-invasive brain stimulation (NIBS) and invasive brain stimulation (IBS). IBS includes deep brain stimulation (DBS), and invasive vagus nerve stimulation (VNS), whereas NIBS includes transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), electroconvulsive treatment (ECT), magnetic seizure therapy (MST), cranial electrostimulation (CES), and non-invasive VNS. We reviewed the cutting-edge research on these brain stimulation techniques and discussed their therapeutic effects on AD. Both IBS and NIBS may have potential to be developed as novel treatments for AD; however, mixed findings may result from different study designs, patients selection, population, or samples sizes. Therefore, the efficacy of NIBS and IBS in AD remains uncertain, and needs to be further investigated. Moreover, more standardized study designs with larger sample sizes and longitudinal follow-up are warranted for establishing a structural guide for future studies and clinical application.

Using transcranial direct current stimulation to treat symptoms in mild cognitive impairment and Alzheimer's disease

Transcranial direct current stimulation (tDCS) has recently been investigated as a potential nonpharmacological treatment for individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD). A comprehensive literature search was performed on tDCS studies published until March 2017 using MEDLINE, Embase and PsychINFO databases. 12 articles with a total of 202 MCI or AD participants were included. Although ten of the 12 studies demonstrated positive findings with tDCS, two studies reported no effect on cognition. There was a wide range of methodological approaches used and in the cognitive functions measured. The variability in treatment response may be related to the heterogeneity in stimulation parameters including the site of stimulation, and cognitive assessments used. Patient-related factors including individual psychological, biological, and physiological status at the time of stimulation may also influence treatment response. We recommend that more comparative studies using similar patient factors and study parameters are needed in order to better understand the efficacy of tDCS in MCI and AD.

Gamma rhythm low field magnetic stimulation alleviates neuropathologic changes and rescues memory and cognitive impairments in a mouse model of Alzheimer's disease

Introduction

The abnormal amyloid β (Aβ) accumulation and Aβ-related neural network dysfunction are considered central to the pathogenesis of Alzheimer's disease (AD) at the early stage. Deep-brain reachable low field magnetic stimulation (DMS), a novel noninvasive approach that was designed to intervene the network activity in brains, has been found to alleviate stress-related cognitive impairments.

Methods

Amyloid precursor protein/presenilin-1 transgenic mice (5XFAD) were treated with DMS, and cognitive behavior and AD-like pathologic changes in the neurochemical and electrophysiological properties in 5XFAD mice were assessed.

Results

We demonstrate that DMS treatment enhances cognitive performances, attenuates Aβ load, upregulates postsynaptic density protein 95 level, and promotes hippocampal long-term potentiation in 5XFAD mouse brain. Intriguingly, the gamma burst magnetic stimulation reverses the aberrant gamma oscillations in the transgenic hippocampal network.

Discussion

This work establishes a solid foundation for the effectiveness of DMS in treating AD and proposes a future study of gamma rhythm stimulation on reorganizing rhythmic neural activity in AD brain.

Neuromodulation Treatments for Geriatric Mood and Cognitive Disorders

There is increasing evidence for the efficacy of neuromodulation in the treatment of resistant mood disorders and emerging data supporting the use of neuromodulation in cognitive disorders. A significant minority of depressed elders do not respond to pharmacotherapy and/or psychotherapy. This has led clinicians to recommend the increasing use of electroconvulsive therapy (ECT) in the treatment of medication-resistant or life-threatening geriatric depression. Multiple studies have supported the safety and efficacy of ECT in the elderly, yet ECT is associated with side effects including cardiovascular and cognitive side effects. Neuromodulation therapies have the potential for providing effective treatment for treatment-resistant older adults with reduced side effects and this review will outline the risks and benefits of neuromodulation treatment in geriatric psychiatry. There is also emerging evidence of the efficacy of neuromodulation devices in the treatment of cognitive disorders. Pharmacotherapy has been largely ineffective in changing the course of neurodegenerative diseases causing dementia and other treatments are clearly needed. This review will outline the available evidence for neuromodulation in the treatment of mood and cognitive disorders in the elderly.

[Repetitive transcranial magnetic stimulation: A potential therapy for cognitive disorders?]

Considering the limited effectiveness of drugs treatments in cognitive disorders, the emergence of noninvasive techniques to modify brain function is very interesting. Among these techniques, repetitive transcranial magnetic stimulation (rTMS) can modulate cortical excitability and have potential therapeutic effects on cognition and behaviour. These effects are due to physiological modifications in the stimulated cortical tissue and their associated circuits, which depend on the parameters of stimulation. The objective of this article is to specify current knowledge and efficacy of rTMS in cognitive disorders. Previous studies found very encouraging results with significant improvement of higher brain functions. Nevertheless, these few studies have limits: a few patients were enrolled, the lack of control of the mechanisms of action by brain imaging, insufficiently formalized technique and variability of cognitive tests. It is therefore necessary to perform more studies, which identify statistical significant improvement and to specify underlying mechanisms of action and the parameters of use of the rTMS to offer rTMS as a routine therapy for cognitive dysfunction.

Repetitive Transcranial Magnetic Stimulation as an Alternative Therapy for Cognitive Impairment in Alzheimer's Disease: A Meta-Analysis

BACKGROUND

Recent studies have indicated that repetitive transcranial magnetic stimulation (rTMS) could improve cognitive function in people with Alzheimer's disease (AD). Yet the results are inconclusive.

OBJECTIVE

This meta-analysis aimed to evaluate recent rTMS studies conducted in mild to moderate AD patients.

METHODS

PubMed, Embase, MEDLINE databases and Science Direct were searched for studies of rTMS treatment on AD patients with cognitive impairment published before February 2015. The relevant primary outcomes of cognition were extracted from those included studies. A crude standardized mean difference (SMD) with 95% confidence interval (CI) was calculated by using random effect models.

RESULTS

Seven studies with a total of 94 mild to moderate AD patients were included in this meta-analysis. A significant overall rTMS treatment effect on cognition was found for all AD patients (p = 0.0008, SMD = 1.00, 95% CI = 0.41-1.58). Stratification analysis showed that this effect is stimulation frequency- and hemisphere-dependent. High frequency stimulation (>1.0 Hz) (p <  0.05) but not low frequency stimulation (≤1.0 Hz) (p >  0.05) was significantly effective in improving the cognition of AD patients. Further, rTMS stimulation on right dorsolateral prefrontal cortex (DLPFC) and bilateral DLPFC (p <  0.05), but not on the left DLPFC (p >  0.05) was significantly effective in improving cognitive function of AD patients. A significant effect was observed in the rTMS subgroup (p <  0.05), rather than in the rTMS+drug subgroup (p >  0.05).

CONCLUSION

This meta-analysis supports that high frequency rTMS stimulation on right- or bilateral-DLPFC has significant therapeutic effect on cognitive function in patients with mild to moderate AD. Due to small number of studies included, more well-controlled rTMS studies should be evaluated in AD patients in the future.

Adjuvant transcranial direct current stimulation for treating Alzheimer's disease: A case study

We report the case of a 73-year-old male patient with Alzheimer's disease who underwent 10-daily transcranial direct current stimulation (tDCS) sessions. tDCS was applied over the left dorsolateral prefrontal cortex as an adjuvant to the traditional treatment that the patient was receiving, which consisted of anticholinergic medication and cognitive training. The data were qualitatively analyzed and are presented in an analytic and structured form. The effects on cognitive performance were evaluated using the Alzheimer's Disease Assessment Scale-cognitive subscale as the primary outcome. Secondary outcomes were assessed with a set of tests consisting of the Neuropsychiatric Inventory, the Blessed Dementia Scale and the Disability Assessment for Dementia. The data obtained revealed that the application of tDCS had a stabilizing effect on overall patient cognitive function and led to improved performance on all the secondary outcome tests. These preliminary results indicate that tDCS is a potential adjuvant therapeutic tool for cognitive rehabilitation in Alzheimer's disease .

Treatment of Alzheimer's Disease with Repetitive Transcranial Magnetic Stimulation Combined with Cognitive Training: A Prospective, Randomized, Double-Blind, Placebo-Controlled Study

BACKGROUND AND PURPOSE

Repetitive transcranial magnetic stimulation (rTMS) has been examined as a potential treatment for many neurological disorders. High-frequency rTMS in particular improves cognitive functions such as verbal fluency and memory. This study explored the effect of rTMS combined with cognitive training (rTMS-COG) on patients with Alzheimer's disease (AD).

METHODS

A prospective, randomized, double-blind, placebo-controlled study was performed with 27 AD patients (18 and 8 in the treatment and sham groups, respectively, and 1 drop-out). The participants were categorized into mild [Mini-Mental State Examination (MMSE) score=21-26] and moderate (MMSE score=18-20) AD groups. The rTMS protocols were configured for six cortical areas (both dorsolateral prefrontal and parietal somatosensory associated cortices and Broca's and Wernicke's areas; 10 Hz, 90-110% intensity, and 5 days/week for 6 weeks). Neuropsychological assessments were performed using the AD Assessment Scale-cognitive subscale (ADAS-cog), Clinical Global Impression of Change (CGIC), and MMSE before, immediately after, and 6 weeks after the end of rTMS-COG treatment.

RESULTS

Data from 26 AD patients were analyzed in this study. There was no significant interactive effect of time between the groups. The ADAS-cog score in the treatment group was significantly improved compared to the sham group (4.28 and 5.39 in the treatment group vs. 1.75 and 2.88 in the sham group at immediately and 6 weeks after treatment, respectively). The MMSE and CGIC scores were also improved in the treatment group. Based on subgroup analysis, the effect of rTMS-COG was superior for the mild group compared to the total patients, especially in the domains of memory and language.

CONCLUSIONS

The present results suggest that rTMS-COG represents a useful adjuvant therapy with cholinesterase inhibitors, particularly during the mild stage of AD. The effect of rTMS-COG was remarkable in the memory and language domains, which are severely affected by AD.

[Assessment of 10 years of memory consultations in the Franche-Comté: Description and analysis of the RAPID regional database]

The aim of this study was to evaluate the impact, on a regional scale (Franche-Comté), of 3 National Alzheimer care plans, particularly concerning the development of the offer of care management by clinicians as well as the panel of diagnoses concerned. Data on sociodemographic, neuropsychological and diagnostic characteristics were retrieved from the RAPID regional database between 1st January 2003 and 31st December 2012. These analyses focused exclusively on patients who had an initial consultation (n=12,017) during the same period. The existence of a previously established health network capable of carrying out governmental health plans has produced an effective interface between regional administrative structures responsible for the implementation of these plans and health professionals responsible for carrying out them out. This network study, the use of a battery of tests and a common software database have enabled the development of patient care management throughout the Franche-Comté region. It also showed the diversification of diagnoses mentioned over the past years as well as changes in clinical practices on how to address the issue of cognitive impairment.

Neurostimulation in Alzheimer's disease: from basic research to clinical applications

The development of different methods of brain stimulation provides a promising therapeutic tool with potentially beneficial effects on subjects with impaired cognitive functions. We performed a systematic review of the studies published in the field of neurostimulation in Alzheimer's disease (AD), from basic research to clinical applications. The main methods of non-invasive brain stimulation are repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Preliminary findings have suggested that both techniques can enhance performances on several cognitive functions impaired in AD. Another non-invasive emerging neuromodulatory approach, the transcranial electromagnetic treatment, was found to reverse cognitive impairment in AD transgenic mice and even improves cognitive performance in normal mice. Experimental studies suggest that high-frequency electromagnetic fields may be critically important in AD prevention and treatment through their action at mitochondrial level. Finally, the application of a widely known invasive technique, the deep brain stimulation (DBS), has increasingly been considered as a therapeutic option also for patients with AD; it has been demonstrated that DBS of fornix/hypothalamus and nucleus basalis of Meynert might improve or at least stabilize cognitive functioning in AD. Initial encouraging results provide support for continuing to investigate non-invasive and invasive brain stimulation approaches as an adjuvant treatment for AD patients.

Incoordination between spikes and LFPs in Aβ1-42-mediated memory deficits in rats

Alzheimer's disease (AD) is a neurodegenerative disease that gradually induces cognitive deficits. Impairments of working memory have been typically observed in AD. It is well known that spikes and local field potentials (LFPs) as well as the coordination between them encode information in normal brain function. However, the abnormal coordination between spikes and LFPs in the cognitive deficits of AD has remained largely unexplored. As amyloid-β peptide (Aβ) is a causative factor for the cognitive impairments of AD, developing a mechanistic understanding of the contribution of Aβ to cognitive impairments may yield important insights into the pathophysiology of AD. In the present study, we simultaneously recorded spikes and LFPs from multiple electrodes implanted in the prefrontal cortex of rats (control and intra-hippocampal Aβ injection group) that performed a Y-maze working memory task. The information changes in spikes and LFPs during the task were assessed by calculation of entropy. Then the coordination between spikes and LFPs was estimated by the correlation of LFP entropy and spike entropy. Compared with the control group, the Aβ group showed significantly weaker coordination between spikes and LFPs. Our results indicate that the incoordination between spikes and LFPs may provide a potential mechanism for the cognitive deficits in working memory of AD.

Transcranial magnetic stimulation and transcranial direct current stimulation: treatments for cognitive and neuropsychiatric symptoms in the neurodegenerative dementias?

Introduction

Two methods of non-invasive brain stimulation, transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), have demonstrable positive effects on cognition and can ameliorate neuropsychiatric symptoms such as depression. Less is known about the efficacy of these approaches in common neurodegenerative diseases. In this review, we evaluate the effects of TMS and tDCS upon cognitive and neuropsychiatric symptoms in the major dementias, including Alzheimer’s disease (AD), vascular dementia (VaD), dementia with Lewy bodies (DLB), Parkinson’s disease with dementia (PDD), and frontotemporal dementia (FTD), as well as the potential pre-dementia states of Mild Cognitive Impairment (MCI) and Parkinson’s disease (PD).

Methods

PubMed (until 7 February 2014) and PsycINFO (from 1967 to January Week 3 2014) databases were searched in a semi-systematic manner in order to identify relevant treatment studies. A total of 762 studies were identified and 32 studies (18 in the dementias and 14 in PD populations) were included.

Results

No studies were identified in patients with PDD, FTD or VaD. Of the dementias, 13 studies were conducted in patients with AD, one in DLB, and four in MCI. A total of 16 of the 18 studies showed improvements in at least one cognitive or neuropsychiatric outcome measure. Cognitive or neuropsychiatric improvements were observed in 12 of the 14 studies conducted in patients with PD.

Conclusions

Both TMS and tDCS may have potential as interventions for the treatment of symptoms associated with dementia and PD. These results are promising; however, available data were limited, particularly within VaD, PDD and FTD, and major challenges exist in order to maximise the efficacy and clinical utility of both techniques. In particular, stimulation parameters vary considerably between studies and are likely to subsequently impact upon treatment efficacy.

Transcranial magnetic stimulation (TMS)/repetitive TMS in mild cognitive impairment and Alzheimer's disease

Several Transcranial Magnetic Stimulation (TMS) techniques can be applied to noninvasively measure cortical excitability and brain plasticity in humans. TMS has been used to assess neuroplastic changes in Alzheimer's disease (AD), corroborating findings that cortical physiology is altered in AD due to the underlying neurodegenerative process. In fact, many TMS studies have provided physiological evidence of abnormalities in cortical excitability, connectivity, and plasticity in patients with AD. Moreover, the combination of TMS with other neurophysiological techniques, such as high-density electroencephalography (EEG), makes it possible to study local and network cortical plasticity directly. Interestingly, several TMS studies revealed abnormalities in patients with early AD and even with mild cognitive impairment (MCI), thus enabling early identification of subjects in whom the cholinergic degeneration has occurred. Furthermore, TMS can influence brain function if delivered repetitively; repetitive TMS (rTMS) is capable of modulating cortical excitability and inducing long-lasting neuroplastic changes. Preliminary findings have suggested that rTMS can enhance performances on several cognitive functions impaired in AD and MCI. However, further well-controlled studies with appropriate methodology in larger patient cohorts are needed to replicate and extend the initial findings. The purpose of this paper was to provide an updated and comprehensive systematic review of the studies that have employed TMS/rTMS in patients with MCI and AD.

Open-label, short-term, repetitive transcranial magnetic stimulation in patients with Alzheimer's disease with functional imaging correlates and literature review

BACKGROUND

Accumulating evidence suggests repetitive transcranial magnetic stimulation (rTMS) may be beneficial in ameliorating cognitive deficits in Alzheimer's disease (AD).

METHODS

AD patients received four high-frequency rTMS sessions over the bilateral dorsolateral prefrontal cortex (DLPFC) over two weeks. Structured cognitive assessments were administered at baseline, at 2 weeks after completion of rTMS, and at 4 weeks post treatment. At these same times, tolerant patients underwent functional magnetic resonance imaging (fMRI) while performing structured motor and cognitive tasks. We also reviewed literature regarding the effects of rTMS on cognitive function in AD.

RESULTS

A total of 12 patients were enrolled, eight of whom tolerated the fMRI. Improvement was seen in Boston Diagnostic Aphasia Examination tests of verbal and non-verbal agility 4 weeks post-treatment. The fMRI analysis showed trends for increased activation during cognitive performance tasks immediately after and at 4 weeks post-treatment. Our literature review revealed several double-blind, sham-controlled studies, all showing sustained improvement in cognition of AD patients with rTMS.

CONCLUSIONS

There was improvement in aspects of language after four rTMS treatments, sustained a month after treatment cessation. Our results are consistent with other studies and standardization of treatment protocols using functional imaging may be of benefit.

The contribution of transcranial magnetic stimulation in the diagnosis and in the management of dementia

Transcranial magnetic stimulation (TMS) is emerging as a promising tool to non-invasively assess specific cortical circuits in neurological diseases. A number of studies have reported the abnormalities in TMS assays of cortical function in dementias. A PubMed-based literature review on TMS studies targeting primary and secondary dementia has been conducted using the key words "transcranial magnetic stimulation" or "motor cortex excitability" and "dementia" or "cognitive impairment" or "memory impairment" or "memory decline". Cortical excitability is increased in Alzheimer's disease (AD) and in vascular dementia (VaD), generally reduced in secondary dementias. Short-latency afferent inhibition (SAI), a measure of central cholinergic circuitry, is normal in VaD and in frontotemporal dementia (FTD), but suppressed in AD. In mild cognitive impairment, abnormal SAI may predict the progression to AD. No change in cortical excitability has been observed in FTD, in Parkinson's dementia and in dementia with Lewy bodies. Short-interval intracortical inhibition and controlateral silent period (cSP), two measures of gabaergic cortical inhibition, are abnormal in most dementias associated with parkinsonian symptoms. Ipsilateral silent period (iSP), which is dependent on integrity of the corpus callosum is abnormal in AD. While single TMS measure owns low specificity, a panel of measures can support the clinical diagnosis, predict progression and possibly identify earlier the "brain at risk". In dementias, TMS can be also exploited to select and evaluate the responders to specific drugs and, it might become a rehabilitative tool, in the attempt to restore impaired brain plasticity.

Cognitive effects of repetitive transcranial magnetic stimulation in patients with neurodegenerative diseases - clinician's perspective

Repetitive transcranial magnetic stimulation (rTMS) represents a promising tool for studying and influencing cognition in people with neurodegenerative diseases. This procedure is noninvasive and painless, and it does not require the use of anesthesia or pharmacological substances. In this systematic critical review we report outcomes from research focused on behavioral cognitive effects induced by rTMS in patients with Alzheimer's disease (AD), Parkinson's disease (PD), and mild cognitive impairment (MCI) preceding AD. There are still major limitations to rTMS use, such as a poor understanding of its after-effects and inter-individual variability in their magnitude, discrepancies in stimulation protocols and study designs, varied selection of the specific stimulated areas and control procedures, and neuropsychological methods for assessment of after-effects; hence, the results of the present research can only be considered preliminary. The future directions are discussed.

Ethics of the electrified mind: defining issues and perspectives on the principled use of brain stimulation in medical research and clinical care

In recent years, non-pharmacologic approaches to modifying human neural activity have gained increasing attention. One of these approaches is brain stimulation, which involves either the direct application of electrical current to structures in the nervous system or the indirect application of current by means of electromagnetic induction. Interventions that manipulate the brain have generally been regarded as having both the potential to alleviate devastating brain-related conditions and the capacity to create unforeseen and unwanted consequences. Hence, although brain stimulation techniques offer considerable benefits to society, they also raise a number of ethical concerns. In this paper we will address various dilemmas related to brain stimulation in the context of clinical practice and biomedical research. We will survey current work involving deep brain stimulation, transcranial magnetic stimulation and transcranial direct current stimulation. We will reflect upon relevant similarities and differences between them, and consider some potentially problematic issues that may arise within the framework of established principles of medical ethics: nonmaleficence and beneficence, autonomy, and justice.

Dementia

Transcranial magnetic stimulation (TMS) has been used extensively to characterize motor system pathophysiology in Alzheimer's disease (AD) and other forms of dementia, as well to monitor the effects of certain pharmacological agents. Among the studies focusing on motor cortical excitability measures, the most consistent finding is a significant reduction of short-latency afferent inhibition (SAI) in AD and other forms of dementia in which the cholinergic system is affected, such as dementia with Lewy bodies. SAI evaluation may thus provide a reliable biomarker of cortical cholinergic dysfunction in dementias. Moreover, most TMS studies have demonstrated cortical hyperexcitability and asymptomatic motor cortex functional reorganization in the early stages of the disease. Integrated approaches utilizing TMS together with high-density EEG have indicated impaired cortical plasticity and functional connectivity across different neural networks in AD. Paired associative stimulation-induced plasticity has also been found to be abnormal in patients with AD. The development of novel noninvasive methods of brain stimulation, in particular repetitive TMS (rTMS) and transcranial direct current stimulation (tDCS), has increased the interest in neuromodulatory techniques as potential therapeutic tools for cognitive rehabilitation in AD. Preliminary studies have revealed that rTMS and tDCS can induce beneficial effects on specific cognitive functions in AD. Future studies are warranted to replicate and extend the initial findings.

Learning and memory

Learning and memory functions are crucial in the interaction of an individual with the environment and involve the interplay of large, distributed brain networks. Recent advances in technologies to explore neurobiological correlates of neuropsychological paradigms have increased our knowledge about human learning and memory. In this chapter we first review and define memory and learning processes from a neuropsychological perspective. Then we provide some illustrations of how noninvasive brain stimulation can play a major role in the investigation of memory functions, as it can be used to identify cause-effect relationships and chronometric properties of neural processes underlying cognitive steps. In clinical medicine, transcranial magnetic stimulation may be used as a diagnostic tool to understand memory and learning deficits in various patient populations. Furthermore, noninvasive brain stimulation is also being applied to enhance cognitive functions, offering exciting translational therapeutic opportunities in neurology and psychiatry.