High-frequency repetitive transcranial magnetic stimulation (rTMS) improves neurocognitive function in bipolar disorder

Cognitive rehabilitation in bipolar spectrum disorder: A systematic review

Background and objectives

Neurocognitive deficits in bipolar disorder (BD) have a negative impact on the quality of life, even during the euthymic phase. And many studies conducted to improve cognitive deficits in bipolar disorder. This systematic review aims to summarize studies on cognitive rehabilitation (CR) conducted in bipolar patients and evaluate its impact on neurocognitive deficits. The primary objective is to explore how CR interventions can enhance cognitive functioning, treatment outcomes, and overall quality of life in this population.

Methods

A comprehensive search was conducted on PubMed, Google Scholar, Scopus, Embase, and PsycINFO databases from 1950 to 2023, following the 2015 PRISMA-P guidelines, using search terms related to BD and CR.

Results

The initial search yielded 371 titles across the five databases. After applying inclusion and exclusion criteria through screening, a total of 23 articles were included in the study. The selected articles evaluated verbal memory, attention, executive functions, and social cognition.

Conclusion

The findings suggest that CR can be an effective treatment approach for bipolar patients, aimed at enhancing their cognitive abilities, treatment outcomes, and overall quality of life. The primary finding of this study indicates that cognitive-behavioral therapy (CBT) protocols, skill training, and homework exercises, which offer a daily structure, social support, and opportunities for exchanging coping strategies, are more effective in enhancing cognitive functions. However, it is important to acknowledge the notable limitations of this review. Firstly, we did not assess the methodological rigor of the included studies. Additionally, there was a lack of detailed analysis regarding specific cognitive rehabilitation approaches that adhere to core CR principles, resulting in increased heterogeneity within the reviewed studies.

Comparing different non-invasive brain stimulation interventions for bipolar depression treatment: A network meta-analysis of randomized controlled trials

Non-invasive brain stimulation (NIBS) is a promising treatment for bipolar depression. We systematically searched for randomized controlled trials on NIBS for treating bipolar depression (INPLASY No: 202340019). Eighteen articles (N = 617) were eligible for network meta-analysis. Effect sizes were reported as standardized mean differences (SMDs) or odds ratios (ORs) with 95% confidence intervals (CIs). Anodal transcranial direct current stimulation over F3 plus cathodal transcranial direct current stimulation over F4 (a-tDCS-F3 +c-tDCS-F4; SMD = -1.18, 95%CIs = -1.66 to -0.69, N = 77), high-definition tDCS over F3 (HD-tDCS-F3; -1.17, -2.00 to -0.35, 25), high frequency deep transcranial magnetic stimulation (HF-dTMS; -0.81, -1.62 to -0.001, 25), and high frequency repetitive TMS over F3 plus low frequency repetitive TMS over F4 (HF-rTMS-F3 +LF-rTMS-F4; -0.77, -1.43 to -0.11, 38) significantly improved depressive symptoms compared to sham controls. Only a-tDCS-F3 +c-tDCS-F4 (OR = 4.53, 95%CIs = 1.51-13.65) and HF-rTMS-F3 +LF-rTMS-F4 (4.69, 1.02-21.56) showed higher response rates. No active NIBS interventions exhibited significant differences in dropout or side effect rates, compared with sham controls.

Effects of intermittent theta-burst transcranial magnetic stimulation on cognition and hippocampal volumes in bipolar depression

INTRODUCTION

Repetitive transcranial magnetic stimulation (TMS) is increasingly used to treat neurocognitive symptoms in mood disorders. Intermittent theta burst stimulation (iTBS) is a brief version of TMS that may preferentially target cognitive functions. This study evaluated whether iTBS leads to cognitive improvements and associated increased hippocampal volumes in bipolar depression.

METHODS

In a two-site double-blind randomised sham controlled trial (NCT02749006), 16 patients received active iTBS to the Left Dorsolateral Prefrontal Cortex (DLPF) and 15 patients received sham stimulation across four weeks. A composite neuropsychological score and declarative memory scores served as the cognitive outcomes. Hippocampal volumes were derived from T1 weighted MRI scans using the longitudinal ComBat method to harmonise data across sites.

RESULTS

No significant improvements were observed in any cognitive variables in the active relative to the sham group; however, there was a trend for increased left hippocampal volume in the former. Left hippocampal volume increases were associated with improvements in nonverbal memory in the active group.

CONCLUSIONS

Although cognitive improvements were not associated with iTBS, the finding that hippocampal volume increases were associated with memory improvement suggests there may be some level of prefrontal-temporal neuroplasticity that could support cognitive change in future studies of iTBS in bipolar disorder.

Cognition in Bipolar Disorder: An Update for Clinicians

Bipolar disorder is associated with cognitive deficits, which persist across mood states and affect functional outcomes. This article provides an overview of recent progress in measuring cognition in bipolar disorder and its implications for both research and clinical practice. The authors summarize work conducted over the past decade that has helped guide researchers and clinicians in the appropriate measurement of cognitive functioning in bipolar disorder, the design of research studies targeting this domain for treatment, and the implementation of screening and psychoeducational tools in the clinic. Much of this work was conducted by the International Society for Bipolar Disorders Targeting Cognition Task Force. Here, the authors also highlight the need for clinicians to be informed about this aspect of illness and to be equipped with the necessary information to assess, track, and intervene on cognitive problems when appropriate. Finally, the article identifies gaps in the literature and suggests potential future directions for research in this area.

10 Hz repetitive transcranial magnetic stimulation (rTMS) may improve cognitive function: An exploratory study of schizophrenia patients with auditory hallucinations

Objectives

Cognitive impairment in schizophrenia patients with auditory hallucinations is more prominent compared to those without. Our study aimed to investigate the cognitive improvement effects of 10 Hz repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (DLPFC) in schizophrenia with auditory hallucinations.

Methods

A total of 60 schizophrenic patients with auditory hallucinations in this study were randomly assigned to sham or active group. Both groups received 10 Hz or sham rTMS targeted in left DLPFC for 20 sessions. The Positive and Negative Syndrome Scale (PANSS), the Auditory Hallucination Rating Scale (AHRS), the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and the Udvalg for Kliniske Under-sogelser (UKU) side effect scale were used to measure psychiatric symptoms, auditory hallucinations, cognition, and side reaction, respectively.

Results

Our results indicated that the active group experienced greater improvements in RBANS-total score (P = 0.043) and immediate memory subscale score (P = 0.001). Additionally, the PANSS-total score, negative and positive subscale score were obviously lower in the active group compared to the sham group (all P < 0.050). Furthermore, our study found that the improvement of RBANS-total score was positively associated with the decline of positive factor score, and the improvement of language score in RBANS was positively associated with the reduction in PANSS-total scale, negative and positive subscale score in the real stimulation group (all P < 0.050).

Conclusion

Our results demonstrated that a four-week intervention of 10 Hz rTMS over the left DLPFC can improve cognition (particularly immediate memory) among schizophrenia patients with auditory hallucinations. Future studies with larger sample size are needful to verify our preliminary findings.

Targeted visual cortex stimulation (TVCS): a novel neuro-navigated repetitive transcranial magnetic stimulation mode for improving cognitive function in bipolar disorder

A more effective and better-tolerated site for repetitive transcranial magnetic stimulation (rTMS) for treating cognitive dysfunction in patients with bipolar disorder (BD) is needed. The primary visual cortex (V1) may represent a suitable site. To investigate the use of the V1, which is functionally linked to the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC), as a potential site for improving cognitive function in BD. Seed-based functional connectivity (FC) analysis was used to locate targets in the V1 that had significant FC with the DLPFC and ACC. Subjects were randomly assigned to 4 groups, namely, the DLPFC active-sham rTMS (A1), DLPFC sham-active rTMS (A2), ACC active-sham rTMS (B1), and ACC sham-active rTMS groups (B2). The intervention included the rTMS treatment once daily, with five treatments a week for four weeks. The A1 and B1 groups received 10 days of active rTMS treatment followed by 10 days of sham rTMS treatment. The A2 and B2 groups received the opposite. The primary outcomes were changes in the scores of five tests in the THINC-integrated tool (THINC-it) at week 2 (W2) and week 4 (W4). The secondary outcomes were changes in the FC between the DLPFC/ACC and the whole brain at W2 and W4. Of the original 93 patients with BD recruited, 86 were finally included, and 73 finished the trial. Significant interactions between time and intervention type (Active/Sham) were observed in the scores of the accuracy of the Symbol Check in the THINC-it tests at baseline (W0) and W2 in groups B1 and B2 (F = 4.736, p = 0.037) using a repeated-measures analysis of covariance approach. Group B1 scored higher in the accuracy of Symbol Check at W2 compared with W0 (p < 0.001), while the scores of group B2 did not differ significantly between W0 and W2. No significant interactions between time and intervention mode were seen between groups A1 and A2, nor was any within-group significance of FC between DLPFC/ACC and the whole brain observed between baseline (W0) and W2/W4 in any group. One participant in group B1 experienced disease progression after 10 active and 2 sham rTMS sessions. The present study demonstrated that V1, functionally correlated with ACC, is a potentially effective rTMS stimulation target for improving neurocognitive function in BD patients. Further investigation using larger samples is required to confirm the clinical efficacy of TVCS.

Association between daily dose and efficacy of rTMS over the left dorsolateral prefrontal cortex in depression: A meta-analysis

Repetitive transcranial magnetic stimulation (rTMS) is a well-established, safe, and effective brain stimulation technique for depression; however, uniform parameters have not been used in clinical practice. The aim of this study was to identify the parameters that affect rTMS effectiveness and ascertain the range in which that parameter has optimal efficacy. A meta-analysis of sham-controlled trials using rTMS delivered over the left dorsolateral prefrontal cortex (DLPFC) in depression was conducted. In the meta-regression and subgroup analyses, all rTMS stimulation parameters were extracted and their association with efficacy was investigated. Of the 17,800 references, 52 sham-controlled trials were included. Compared to sham controls, our results demonstrated a significant improvement in depressive symptoms at the end of treatment. According to the results of meta-regression, the number of pulses and sessions per day correlated with rTMS efficacy; however, the positioning method, stimulation intensity, frequency, number of treatment days, and total pulses did not. Furthermore, subgroup analysis revealed that the efficacy was correspondingly better in the group with higher daily pulses. In clinical practice, increasing the number of daily pulses and sessions may improve the effectiveness of rTMS.

An update on potential pharmacotherapies for cognitive impairment in bipolar disorder

INTRODUCTION

Cognitive impairment is a core feature of bipolar disorder (BD) that impedes recovery by preventing the return to optimal socio-occupational functioning and reducing quality of life. Presently, there are no efficacious treatments for cognitive impairment in BD, but many pharmacological interventions are being considered as they have the potential to target the underlying pathophysiology of the disorder.

AREAS COVERED

This review summarizes the available evidence for pharmacological interventions for cognitive impairment in bipolar disorder. We searched PubMed, MedLine, and PsycInfo from inception to December 1^st, 2022. Traditional treatments, such as lithium, anticonvulsants (lamotrigine), antipsychotics (aripiprazole, asenapine, cariprazine, lurasidone, and olanzapine), antidepressants (vortioxetine, fluoxetine, and tianeptine) and psychostimulants (modafinil), and emerging interventions, such as acetylcholinesterase inhibitors (galantamine and donepezil), dopamine agonists (pramipexole), erythropoietin, glucocorticoid receptor antagonists (mifepristone), immune modulators (infliximab, minocycline and doxycycline), ketamine, metabolic agents (insulin, metformin, and liraglutide), probiotic supplements, and Withania somnifera are discussed.

EXPERT OPINION

The investigation of interventions for cognitive impairment in BD is a relatively under-researched area. In the past, methodological pitfalls in BD cognition trials have also been a critical limiting factor. Expanding on the existing literature and identifying novel pharmacological and non-pharmacological treatments for cognitive impairment in BD should be a priority.

Brain stimulation treatment for bipolar disorder

AIMS

Bipolar disorders are clinically complex, chronic and recurrent disorders. Few treatment options are effective across hypomanic, manic, depressive and mixed states and as continuation or maintenance treatment after initial symptom remission. The aim of this review was to provide an up-to-date overview of research on the efficacy, tolerability and cognitive effects of electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), magnetic seizure therapy (MST), deep brain stimulation (DBS) and vagus nerve stimulation (VNS).

METHODS

References included in this review were identified through multiple searches of the Embase, PubMed/MEDLINE and APA PsycINFO electronic databases for articles published from inception until February 2022. Published reviews, meta-analyses, randomised controlled trials and recent studies were prioritised to provide a comprehensive and up-to-date overview of research on brain stimulation in patients with bipolar disorders.

RESULTS

The evidence base for brain stimulation as an add-on or alternative to pharmacological and psychological treatments in patients with bipolar disorders is limited but rapidly expanding. Brain stimulation treatments represent an opportunity to treat all bipolar disorder states, including cognitive dysfunction during euthymic periods.

CONCLUSION

Whilst findings to date have been encouraging, larger randomised controlled trials with long-term follow-up are needed to clarify important questions regarding treatment efficacy and tolerability, the frequency of treatment-emergent affective switches and effects on cognitive function.

The Use of Repetitive Transcranial Magnetic Stimulations for the Treatment of Bipolar Disorder: A Scoping Review

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive neuromodulation technique that involves the application of magnetic pulses on hyperactive or hypoactive cortical brain areas. rTMS is considered a high therapeutic tool in many neuropsychiatric conditions. Despite its wide and continuous usage for the treatment of psychiatric disorders, information about the use of rTMS in bipolar disorders is limited and not well-established in the literature. Objectives: This scoping review aims to explore the literature available regarding the application of rTMS for the management of bipolar disorders, to garner evidence in support of it uses in the management of bipolar disorders, and for recommendations on future clinical and research work. Method: We electronically conducted a data search in five research databases (MEDLINE, CINAHL, Psych INFO, SCOPUS, and EMBASE) using all identified keywords across all the databases to identify evidence-based studies. Articles were included if they were published randomized control designs aimed at the use of rTMS in the management of bipolar disorders. Overall, nine studies were eligible for this review. The search results are up to date as of the final date of data search—20 December 2020. Only full-text published articles written in English were reviewed. Review articles on treatment with rTMS for conditions either than bipolar disorders were excluded. Conclusion: The application of rTMS intervention for bipolar disorders looks promising despite the diversity of its outcomes and its clinical significance. However, to be able to draw a definite conclusion on the clinical effectiveness of the technique, more randomized controlled studies with well-defined stimulation parameters need to be conducted with large sample sizes in the future.

Cold Cognition as Predictor of Treatment Response to rTMS; A Retrospective Study on Patients With Unipolar and Bipolar Depression

Background

Cognitive impairments are prevalent in patients with unipolar and bipolar depressive disorder (UDD and BDD, respectively). Considering the fact assessing cognitive functions is increasingly feasible for clinicians and researchers, targeting these problems in treatment and using them at baseline as predictors of response to treatment can be very informative.

Method

In a naturalistic, retrospective study, data from 120 patients (Mean age: 33.58) with UDD (n = 56) and BDD (n = 64) were analyzed. Patients received 20 sessions of bilateral rTMS (10 Hz over LDLPFC and 1 HZ over RDLPFC) and were assessed regarding their depressive symptoms, sustained attention, working memory, and executive functions, using the Beck Depression Inventory (BDI-II) and Neuropsychological Test Automated Battery Cambridge, at baseline and after the end of rTMS treatment course. Generalized estimating equations (GEE) and logistic regression were used as the main statistical methods to test the hypotheses.

Results

Fifty-three percentage of all patients (n = 64) responded to treatment. In particular, 53.1% of UDD patients (n = 34) and 46.9% of BDD patients (n = 30) responded to treatment. Bilateral rTMS improved all cognitive functions (attention, working memory, and executive function) except for visual memory and resulted in more modulations in the working memory of UDD compared to BDD patients. More improvements in working memory were observed in responded patients and visual memory, age, and sex were determined as treatment response predictors. Working memory, visual memory, and age were identified as treatment response predictors in BDD and UDD patients, respectively.

Conclusion

Bilateral rTMS improved cold cognition and depressive symptoms in UDD and BDD patients, possibly by altering cognitive control mechanisms (top-down), and processing negative emotional bias.

Evidence and expert consensus based German guidelines for the use of repetitive transcranial magnetic stimulation in depression

INTRODUCTION

Non-invasive brain stimulation techniques such as repetitive transcranial magnetic stimulation (rTMS) offer a promising alternative to psychotherapeutic and pharmacological treatments for depression. This paper aims to present a practical guide for its clinical implementation based on evidence from the literature as well as on the experience of a group of leading German experts in the field.

METHODS

The current evidence base for the use of rTMS in depression was examined via review of the literature. From the evidence and from clinical experience, recommendations for the use of rTMS in clinical practice were derived. All members of the of the German Society for Brain Stimulation in Psychiatry and all members of the sections Clinical Brain Stimulation and Experimental Brain Stimulation of the German Society for Psychiatry, Psychotherapy, Psychosomatics and Mental Health were invited to participate in a poll on whether they consent with the recommendations.

FINDINGS

Among rTMS experts, a high consensus rate could be identified for clinical practice concerning the setting and the technical parameters of rTMS treatment in depression, indications and contra-indications, the relation of rTMS to other antidepressive treatment modalities and the frequency and management of side effects.

Randomised controlled cognition trials in remitted patients with mood disorders published between 2015 and 2021: A systematic review by the International Society for Bipolar Disorders Targeting Cognition Task Force

BACKGROUND

Cognitive impairments are an emerging treatment target in mood disorders, but currently there are no evidence-based pro-cognitive treatments indicated for patients in remission. With this systematic review of randomised controlled trials (RCTs), the International Society for Bipolar Disorders (ISBD) Targeting Cognition Task force provides an update of the most promising treatments and methodological recommendations.

METHODS

The review included RCTs of candidate pro-cognitive interventions in fully or partially remitted patients with major depressive disorder or bipolar disorder. We followed the procedures of the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) 2020 statement. Searches were conducted on PubMed/MEDLINE, PsycInfo, EMBASE and Cochrane Library from January 2015, when two prior systematic reviews were conducted, until February 2021. Two independent authors reviewed the studies with the Revised Cochrane Collaboration's Risk of Bias tool for Randomised trials.

RESULTS

We identified 16 RCTs (N = 859) investigating cognitive remediation (CR; k = 6; N = 311), direct current or repetitive magnetic stimulation (k = 3; N = 127), or pharmacological interventions (k = 7; N = 421). CR showed most consistent cognitive benefits, with two trials showing improvements on primary outcomes. Neuromodulatory interventions revealed no clear efficacy. Among pharmacological interventions, modafinil and lurasidone showed early positive results. Sources of bias included small samples, lack of pre-screening for objective cognitive impairment, no primary outcome and no information on allocation sequence masking.

CONCLUSIONS

Evidence for pro-cognitive treatments in mood disorders is emerging. Recommendations are to increase sample sizes, pre-screen for impairment in targeted domain(s), select one primary outcome, aid transfer to real-world functioning, investigate multimodal interventions and include neuroimaging.

Altered Spontaneous Brain Activity Patterns in Children With Strabismic Amblyopia After Low-Frequency Repetitive Transcranial Magnetic Stimulation: A Resting-State Functional Magnetic Resonance Imaging Study

Objective

Previous studies have demonstrated altered brain activity in strabismic amblyopia (SA). In this study, low-frequency repetitive transcranial magnetic stimulation (rTMS) was applied in children with strabismic amblyopia after they had undergone strabismus surgery. The effect of rTMS was investigated by measuring the changes of brain features using the amplitude of low-frequency fluctuation (ALFF).

Materials and Methods

In this study, 21 SA patients (12 males and 9 females) were recruited based on their age (7–13 years old), weight, and sex. They all had SA in their left eyes and they received rTMS treatment one month after strabismus surgery. Their vision before and after surgery were categorized as pre-rTMS (PRT) and post-rTMS (POT). All participants received rTMS treatment, underwent magnetic resonance imaging (MRI), and their data were analyzed using the repeated measures t-test. The team used correlation analysis to explore the relationship between logMAR visual acuity and ALFF.

Results

Pre- versus post-rTMS values of ALFF were significantly different within individuals. In the POT group, ALFF values were significantly decreased in the Angular_R (AR), Parietal_Inf_L (PIL), and Cingulum_Mid_R (CMR) while ALFF values were significantly increased in the Fusiform_R (FR) and Frontal_Inf_Orb_L(FIL) compared to the PRT stage.

Conclusion

Our data showed that ALFF recorded from some brain regions was changed significantly after rTMS in strabismic amblyopes. The results may infer the pathological basis of SA and demonstrate that visual function may be improved using rTMS in strabismic amblyopic patients.

Repetitive transcranial magnetic stimulation (rTMS) in bipolar disorder: A systematic review

OBJECTIVES

Repetitive transcranial magnetic stimulation (rTMS) is commonly used in unipolar depression; yet, its evidence in bipolar disorder (BD) is limited. We sought to review the evidence on the use of rTMS across the different stages of BD.

METHODS

MEDLINE database was systematically searched using the PubMed interface following the PRISMA guidelines. Inclusion criteria were as follows: (i) randomized clinical trials (RCTs), open-label studies, and case series; (ii) specific evaluation of the treatment outcomes using psychometric scales; (iii) clinical studies in adults; and (iv) articles in the English language. The systematic review has been registered on PROSPERO (CRD42020192788).

RESULTS

Thirty-one papers were included in the review. Most studies included participants diagnosed with a bipolar depressive episode (N = 24), have yielded mixed findings, and have yet to reach a consensus on the most effective rTMS protocol. Few studies examined the effect of rTMS during manic (N = 5) or mixed episode (N = 1), or as maintenance treatment (N = 1). The limited data thus far suggest rTMS to be relatively safe and well tolerated. Small sample sizes, heterogeneity among study designs, patients and control groups recruited, rTMS parameters, and outcome measures are among the most significant limitations to these studies.

CONCLUSION

The current data regarding the application of rTMS in BD patients remain limited. More adequately powered sham-controlled studies are required to verify its efficacy. Large-scale clinical trials are needed to also determine whether its effects extend to manic and mixed episodes, as well as its role in mood stabilization and amelioration of suicidal behavior.

Neural correlates of semantic ambiguity resolution in paucisymptomatic bipolar disorder patients

In addition to symptoms specifically related to mood dysregulation, patients with bipolar disorder (BD) show frequent alterations in formal thought organization. A disruption in semantic processing, notably in semantic inhibition, is one of the possible mechanisms that might explain this modified organization. However, to date, little is known about these mechanisms and their underlying neural substrates. This study aimed to identify the neural correlates of the semantic inhibition process in BD patients in comparison to healthy controls. Seventeen BD patients and 17 matched controls were recruited and underwent a 3T MRI scan. A semantic ambiguity resolution task was used during the scan to explore semantic inhibition. Whole-brain analyses were conducted on 13 BD patients and 16 controls. When compared to controls, BD patients had stronger activation in the bilateral temporal areas and right middle frontal gyrus, and less activation in the right hippocampus, parahippocampal area, and bilateral precunei. The present study revealed an altered fronto-temporo-parietal semantic inhibition network in BD patients that could reflect compensative mechanisms or modified semantic processing inducing abnormal thought organization, which has a major impact on the occupational and social functioning of the BD population.

Effect of Pharmacological and Neurostimulation Interventions for Cognitive Domains in Patients with Bipolar Disorder: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

The priority of interventions to alleviate cognitive deficits in patients with bipolar disorder (BD) is inconclusive. We systematically evaluate the efficacy of pharmacological or neurostimulation interventions for cognitive function in BD through a network meta-analysis.

METHODS

The PubMed, PsycINFO, Embase, and Cochrane Library databases were searched from database inception to September 30, 2021. Following PRISMA guidelines, all eligible studies were randomized controlled trials of adult bipolar patients that provided detailed cognitive outcomes. Studies were excluded if participants limited to comorbid substance use disorder or the intervention was a psychotherapy. Network meta-analysis comparing different interventions was conducted for 8 cognitive domains. Partially ordered set with Hasse diagram was used to resolve conflicting rankings between outcomes. The study was preregistered on PROSPERO database (CRD42020152044).

RESULTS

Total 21 RCTs including 42 tests for assessing intervention effects on cognition were retrieved. Adjunctive erythropoietin (SMD = 0.61, 95% CI = 0.00-1.23), Withania somnifera (SMD = 0.58, 95% CI = 0.03-1.13), and galantamine (SMD = 1.22, 95% CI = 0.10-2.35) was more beneficial for attention, working memory, and verbal learning in euthymic BD patients than treatment as usual, respectively. Hasse diagram suggested ranking of choice when multiple domains were combined.

CONCLUSION

Considerable variability in measurements of cognitive domains in BD was observed, and no intervention resulted in superior benefits across all domains. We suggested interventions priority can be tailored according to individual patients' cognitive deficits. As current findings from relatively small and heterogeneous dataset, future trials with consensus should be applied for building further evidence.

Repetitive transcranial magnetic stimulation for cognitive function in adults with bipolar disorder: A pilot study

BACKGROUND

Cognitive deficits are prevalent in bipolar disorder and are a significant contributor to negative patient-reported outcomes. Herein we conducted a pilot study of repetitive transcranial magnetic stimulation (rTMS) to improve cognitive function in adults with bipolar disorder.

METHODS

The study was a triple-blinded, randomized, placebo-control trial. Participants (aged 18 to 60) with a diagnosis of DSM-5-defined bipolar disorder (I or II) were recruited and randomized (N=36) to receive either a sham treatment (n=20) or an active rTMS treatment (n=16). Patients completed the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) at baseline and 1-2 weeks after the rTMS intervention.

RESULTS

A significant group by time interaction was observed in the Hopkins Verbal Learning Test-Revised (HVLT-R), (F (1, 34) = 17.0, p < 0.001, partial η² = 0.33). Post-hoc analysis revealed that although both groups did not significantly differ at baseline (p = 0.58), patients in the active rTMS group significantly improved following neurostimulation (p = 0.02) for HVLT-R. Moreover, within-subject analysis indicated that the active rTMS group significantly improved in score from pre-treatment to post-treatment (p < 0.001), while the sham group did not improve (p = 0.94) for HVLT-R. No significant differences were seen in the other cognitive measures.

LIMITATIONS

The study was conducted in a small sample .

CONCLUSION

This pilot study, which was intended to establish feasibility, suggests that rTMS may offer benefit in select domains of cognitive functioning in bipolar disorder. None of the measures across subdomains revealed a dyscognitive effect.

Repetitive transcranial magnetic stimulation during a spatial memory task leads to a decrease in brain metabolic activity

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique that is able to generate causal-based interferences between brain networks and cognitive or behavioral responses. It has been used to improve cognition in several disease models. However, although its exploration in healthy animals is essential to attribute its pure effect in learning and memory processes, studies in this regard are scarce. We aimed to evaluate whether rTMS leads to memory facilitation in healthy rats, and to explore the brain-related oxidative metabolism. We stimulated healthy Wistar rats with a high-frequency (100 Hz) and low-intensity (0.33 T) protocol during three consecutive days and evaluated the effect on the performance of an allocentric spatial reference learning and memory task. Following the last day of learning, we assessed oxidative brain metabolism through quantitative cytochrome c oxidase (CCO) histochemistry. The results showed that rTMS did not improve spatial memory in healthy rats, but the behavioral outcome was accompanied by a CCO reduction in the prefrontal, retrosplenial, parietal, and rhinal cortices, as well as in the striatum, amygdala, septum, mammillary bodies, and the hippocampus, reflecting a lower metabolic activity. In conclusion, rTMS induces a highly efficient use of brain regions associated with spatial memory.

Repetitive Transcranial Magnetic Stimulation (rTMS) Improves the Gait Disorders of Rats Under Simulated Microgravity Conditions Associated With the Regulation of Motor Cortex

In previous studies, it has been proved that repetitive transcranial magnetic stimulation (rTMS) improves dyskinesia induced by conditions such as spinal cord injury, Parkinson diseases and cerebral ischemia. However, it is still unknown whether it can be used as a countermeasure for gait disorders in astronauts during space flight. In this study, we evaluated the effects of rTMS on the rat gait function under simulated microgravity (SM) conditions. The SM procedure continued for consecutive 21 days in male Wistar rats. Meanwhile, the high-frequency rTMS (10 Hz) was applied for 14 days from the eighth day of SM procedure. The behavioral results showed that SM could cause gait disorders such as decreased walking ability and contralateral limb imbalance in rats, which could be reversed by rTMS. Furthermore, rTMS affected the neural oscillations of motor cortex, enhancing in δ (2–4 Hz) band, suppressing in θ (4–7 Hz), and α (7–12 Hz) bands. Additionally, rTMS could activate mTOR in the motor cortex. These data suggests that the improvement effects of rTMS on gait disorders in rats under SM conditions might be associated with its regulation on neural oscillations in the cerebral motor cortex and the expression of some motor-related proteins which may enhance the control of nervous system on muscle function. Based on our results, rTMS can be used as an potential effective supplement in the field of clinical and rehabilitation research to reduce gait disorders caused by the space environment.

Role of rTMS in the treatment of cognitive impairments in Bipolar Disorder and Schizophrenia: a review of Randomized Controlled Trials

BACKGROUND

Schizophrenia (SCZ) and Bipolar Disorder (BD) are severe psychiatric illnesses often characterized by mild-to-severe cognitive deficits. Since available pharmacotherapy showed poor efficacy in treating these cognitive impairments, new strategies are needed. Repeated Transcranial Magnetic Stimulation (rTMS) represents a safe non-invasive technique that has been hypothesized to improve cognitive symptoms in these pathologies. Therefore, our brief review aims at summarizing the results of Randomized Controlled Trials (RCTs) using rTMS for improving cognitive symptoms in SCZ and BD.

METHODS

We performed a bibliographic research on PubMed, Google Scholar and Medline of RCTs conducted in patients with BD and SCZ, which evaluated cognitive outcomes after rTMS treatment.

RESULTS

The inclusion criteria were met by fifteen RCTs, twelve in SCZ and three in BD. Regarding patients with SCZ, the results showed that rTMS seemed to have poor effects on improving cognitive performances, with mixed results also observed for schizoaffective patients. In BD, overall the RCTs showed that rTMS in these patients seemed to improve cognitive domains in euthymic patients, while its effect during acute phases, especially depression, appeared limited.

LIMITATIONS

Studies employed different rTMS protocols and evaluated different cognitive domains.

CONCLUSIONS

Although the available evidence from RCTs evaluating the efficacy of rTMS on cognitive deficits in SCZ and BD are still mixed and heterogenous, overall they suggest that rTMS represents a potential clinical tool that could ameliorate cognitive symptoms, especially in specific patients' subtypes. However, standardized protocols and further research are still necessary to evaluate the real efficacy of rTMS.

Management of cognitive impairment in bipolar disorder: a systematic review of randomized controlled trials

Cognitive impairment is common in bipolar disorder and is emerging as a therapeutic target to enhance quality of life and function. A systematic search was conducted on PubMed, PsycInfo, Cochrane, clinicaltrials.gov, and Embase databases for blinded or open-label randomized controlled trials evaluating the pro-cognitive effects of pharmacological, neurostimulation, or psychological interventions for bipolar disorder. Twenty-two trials were identified, evaluating a total of 16 different pro-cognitive interventions. The methodological quality of the identified trials were assessed using the Cochrane Risk of Bias tool. Currently, no intervention (i.e., pharmacologic, neurostimulation, cognitive remediation) has demonstrated robust and independent pro-cognitive effects in adults with bipolar disorder. Findings are preliminary and methodological limitations limit the interpretation of results. Methodological considerations including, but not limited to, the enrichment with populations with pre-treatment cognitive impairment, as well as the inclusion of individuals who are in remission are encouraged. Future trials may also consider targeting interventions to specific cognitive subgroups and the use of biomarkers of cognitive function.

Repetitive Transcranial Magnetic Stimulation Modulates Frontal and Temporal Time-Varying EEG Network in Generalized Anxiety Disorder: A Pilot Study

Generalized Anxiety Disorder (GAD) is a highly prevalent yet poorly understood chronic mental disorder. Previous studies have associated GAD with excessive activation of the right dorsolateral prefrontal cortex (DLPFC). This study aimed to investigate the effect of low-frequency repetitive transcranial magnetic stimulation (repetitive TMS, rTMS) targeting the right DLPFC on clinical symptoms and TMS-evoked time-varying brain network connectivity in patients with GAD. Eleven patients with GAD received 1 Hz rTMS treatment targeting the right DLPFC for 10 days. The severity of the clinical symptoms was evaluated using the Hamilton Anxiety Scale (HAMA) and the Hamilton Depression Scale (HAMD) at baseline, right after treatment, and at the one-month follow-up. Co-registration of single-pulse TMS (targeting the right DLPFC) and electroencephalography (TMS-EEG) was performed pre- and post-treatment in these patients and 11 healthy controls. Time-varying brain network connectivity was analyzed using the adaptive directed transfer function. The scores of HAMA and HAMD significantly decreased after low-frequency rTMS treatment, and these improvements in ratings remained at the one-month follow-up. Analyses of the time-varying EEG network in the healthy controls showed a continuous weakened connection information outflow in the left frontal and mid-temporal regions. Compared with the healthy controls, the patients with GAD showed weakened connection information outflow in the left frontal pole and the posterior temporal pole at baseline. After 10-day rTMS treatment, the network patterns showed weakened connection information outflow in the left frontal and temporal regions. The time-varying EEG network changes induced by TMS perturbation targeting right DLPFC in patients with GAD were characterized by insufficient information outflow in the left frontal and temporal regions. Low-frequency rTMS targeting the right DLPFC reversed these abnormalities and improved the clinical symptoms of GAD.

Neurocognitive functioning in bipolar disorder: What we know and what we don’t

Introduction: This narrative review of systematic reviews and meta-analyses aims at compiling available evidence in various aspects of neurocognitive functioning in Bipolar Disorder (BD).

Methods: We conducted a MEDLINE literature search and identified 38 relevant systematic reviews and metaanalyses.

Results: Current evidence suggests that BD is associated with cognitive impairment across multiple domains and during all clinical states. However, there is a considerable cognitive heterogeneity within BD, which cannot be explained by clinical subtypes, and the pattern of neurocognitive impairment in BD overlaps with other psychiatric conditions such as major depression and schizophrenia. Residual depressive symptoms, poor clinical course and higher number of manic episodes may negatively impact cognitive performance, which is a major predictor of general functioning in BD. Evidence from available prospective studies does not support the notion of progressive cognitive decline in BD while some evidence exists to suggest patients may show some improvements in cognitive functioning following the first manic episode. Furthermore, a subset of patients may show premorbid cognitive abnormalities that could signal an early neurodevelopmental aetiology. Preliminary findings from small studies identify potential pro-cognitive effects of Cognitive Remediation, erythropoietin, intranasal insulin, lurasidone, mifepristone, repetitive Transcranial Magnetic Stimulation and transcranial Direct Current Stimulation in BD.

Discussion: Longitudinal studies in high-risk individuals can provide a better understanding of the development and progression of neurocognitive impairment in BD. Largescale randomised control trials are needed to compare the pro-cognitive efficacy of various pharmacological and non-pharmacological interventions in different cognitive subgroups of patients at different stages of BD.

Bipolar disorders

Bipolar disorders are a complex group of severe and chronic disorders that includes bipolar I disorder, defined by the presence of a syndromal, manic episode, and bipolar II disorder, defined by the presence of a syndromal, hypomanic episode and a major depressive episode. Bipolar disorders substantially reduce psychosocial functioning and are associated with a loss of approximately 10-20 potential years of life. The mortality gap between populations with bipolar disorders and the general population is principally a result of excess deaths from cardiovascular disease and suicide. Bipolar disorder has a high heritability (approximately 70%). Bipolar disorders share genetic risk alleles with other mental and medical disorders. Bipolar I has a closer genetic association with schizophrenia relative to bipolar II, which has a closer genetic association with major depressive disorder. Although the pathogenesis of bipolar disorders is unknown, implicated processes include disturbances in neuronal-glial plasticity, monoaminergic signalling, inflammatory homoeostasis, cellular metabolic pathways, and mitochondrial function. The high prevalence of childhood maltreatment in people with bipolar disorders and the association between childhood maltreatment and a more complex presentation of bipolar disorder (eg, one including suicidality) highlight the role of adverse environmental exposures on the presentation of bipolar disorders. Although mania defines bipolar I disorder, depressive episodes and symptoms dominate the longitudinal course of, and disproportionately account for morbidity and mortality in, bipolar disorders. Lithium is the gold standard mood-stabilising agent for the treatment of people with bipolar disorders, and has antimanic, antidepressant, and anti-suicide effects. Although antipsychotics are effective in treating mania, few antipsychotics have proven to be effective in bipolar depression. Divalproex and carbamazepine are effective in the treatment of acute mania and lamotrigine is effective at treating and preventing bipolar depression. Antidepressants are widely prescribed for bipolar disorders despite a paucity of compelling evidence for their short-term or long-term efficacy. Moreover, antidepressant prescription in bipolar disorder is associated, in many cases, with mood destabilisation, especially during maintenance treatment. Unfortunately, effective pharmacological treatments for bipolar disorders are not universally available, particularly in low-income and middle-income countries. Targeting medical and psychiatric comorbidity, integrating adjunctive psychosocial treatments, and involving caregivers have been shown to improve health outcomes for people with bipolar disorders. The aim of this Seminar, which is intended mainly for primary care physicians, is to provide an overview of diagnostic, pathogenetic, and treatment considerations in bipolar disorders. Towards the foregoing aim, we review and synthesise evidence on the epidemiology, mechanisms, screening, and treatment of bipolar disorders.

Repetitive Transcranial Magnetic Stimulation in the Treatment of Bipolar Disorder

Bipolar disorder (BD) is a debilitating mood disorder marked by manic, hypomanic and/or mixed or depressive episodes. It affects approximately 1-2% of the population and is linked to high rates of suicide, functional impairment and poorer quality of life. Presently, treatment options for BD are limited. There is a strong evidence base for pharmacological (e.g., lithium) and psychological (e.g., psychoeducation) treatments; however, both of these pose challenges for treatment outcomes (e.g., non-response, side-effects, limited access). Repetitive transcranial magnetic stimulation (rTMS), a non-invasive brain stimulation technique, is a recommended treatment for unipolar depression, but it is unclear whether rTMS is an effective, safe and well tolerated treatment in people with BD. This article reviews the extant literature on the use of rTMS to treat BD across different mood states. We found 34 studies in total (N = 611 patients), with most assessing bipolar depression (n = 26), versus bipolar mania (n = 5), mixed state bipolar (n = 2) or those not in a current affective episode (n = 1). Across all studies, there appears to be a detectable signal of efficacy for rTMS treatment, as most studies report that rTMS treatment reduced bipolar symptoms. Importantly, within the randomised controlled trial (RCT) study designs, most reported that rTMS was not superior to sham in the treatment of bipolar depression. However, these RCTs are based on small samples (NBD ⩽ 52). Reported side effects of rTMS in BD include headache, dizziness and sleep problems. Ten studies (N = 14 patients) reported cases of affective switching; however, no clear pattern of potential risk factors for affective switching emerged. Future adequately powered, sham-controlled trials are needed to establish the ideal rTMS treatment parameters to help better determine the efficacy of rTMS for the treatment of BD.

Associations between cognitive impairment and P300 mean amplitudes in individuals with bipolar disorder in remission

Cognitive functions are often affected during the euthymic state of bipolar disorder (BD). In this study, we investigated the associations among cognitive complaints, objective cognitive functions, and the mean amplitudes of the P300 event-related potential (ERP) wave in individuals with BD. The study population comprised 33 individuals with BD who were in remission and was conducted at Hokkaido University Hospital, Sapporo, Japan. Cognitive complaints were assessed using the Japanese version of the tool named "cognitive complaints in bipolar disorder rating assessment (COBRA)", whereas objective cognitive functions were measured by neuropsychological tests. P300 mean amplitudes were investigated during two- and three-stimulus oddball tasks and showed significant correlations with neuropsychological test scores at all electrode locations, confirming that ERPs and objective cognitive tests that assessed attention and memory function tend to coincide; however, neither P300 amplitudes nor neuropsychological test scores were correlated with COBRA scores. ERPs most likely represent the neurophysiological basis for objective rather than subjective cognitive function in euthymic individuals. Thus, our results suggest that objective cognitive function is related more to P300 mean amplitude scores than subjective cognitive function in individuals with BD.

Neurocognitive impairment and evidence-based treatment options in Bipolar disorder

BACKGROUND

The current paper briefly summarizes the literature on the neurocognitive deficit and its treatment in BD patients.

METHODS

The material was chosen on the basis of previous systematic reviews the author has taken part in.

RESULTS

The data so far suggest that the deficit is qualitatively similar but quantitatively milder in comparison to schizophrenia, it is present already since the first episode, is weakly related to mood symptoms and somewhat stronger to psychotic symptoms, it probably determines much of the disability and treatment is problematic. This deficit is also present during periods of euthymia. The possible adverse effect of psychotropic medication is rather small if any at all and is confounded by the specific clinical symptoms, for which medication is used for their treatment. This is especially true concerning antipsychotics and psychotic symptoms. The origin and the etiopathogenesis of the core neurocognitive impairment remain elusive. The presence of a neurodegenerative and of a neurodevelopmental component has both data in favor and against and they are both the focus of debate.

CONCLUSIONS

Treatment of the neurocognitive deficit and restoration of functioning is problematic. The data are limited and treatment options are few and with a weak overall effect. Pharmacological treatments, ECT and rTMS present some hard data, while the literature is inconclusive concerning psychotherapeutic interventions.