Intermittent theta-burst stimulation alleviates hypoxia-ischemia-caused myelin damage and neurologic disability

Neonatal hypoxia-ischemia (HI) results in behavioral deficits, characterized by neuronal injury and retarded myelin formation. To date, limited treatment methods are available to prevent or alleviate neurologic sequelae of HI. Intermittent theta-burst stimulation (iTBS), a non-invasive therapeutic procedure, is considered a promising therapeutic tool for treating some neurocognitive disorders and neuropsychiatric diseases. Hence, this study aims to investigate whether iTBS can prevent the negative behavioral manifestations of HI and explore the mechanisms for associations. We exposed postnatal day 10 Sprague-Dawley male and female rats to 2 h of hypoxia (6% O2) following right common carotid artery ligation, resulting in oligodendrocyte (OL) dysfunction, including reduced proliferation and differentiation of oligodendrocyte precursor cells (OPCs), decreased OL survival, and compromised myelin in the corpus callosum (CC) and hippocampal dentate gyrus (DG). These alterations were concomitant with cognitive dysfunction and depression-like behaviors. Crucially, early iTBS treatment (15 G, 190 s, seven days, initiated one day post-HI) significantly alleviated HI-caused myelin damage and mitigated the neurologic sequelae both in male and female rats. However, the late iTBS treatment (initiated 18 days after HI insult) could not significantly impact these behavioral deficits. In summary, our findings support that early iTBS treatment may be a promising strategy to improve HI-induced neurologic disability. The underlying mechanisms of iTBS treatment are associated with promoting the differentiation of OPCs and alleviating myelin damage.

Sex differences in brain excitability revealed by concurrent iTBS/fNIRS

Sex differences have been claimed an imperative factor in the optimization of psychiatric treatments. Intermittent theta-burst stimulation (iTBS), a patterned form of repetitive transcranial magnetic stimulation, is a promising non-invasive treatment option. Here, we investigated whether the real-time neural response to iTBS differs between men and women, and which mechanisms may mediate these differences. To this end, we capitalized on a concurrent iTBS/functional near-infrared spectroscopy setup over the left dorsolateral prefrontal cortex, a common clinical target, to test our assumptions. In a series of experiments, we show (1) a biological sex difference in absolute hemoglobin concentrations in the left dorsolateral prefrontal cortex in healthy participants; (2) that this sex difference is amplified by iTBS but not by cognitive tasks; and (3) that the sex difference amplified by iTBS is modulated by stimulation intensity. These results inform future stimulation treatment optimizations towards precision psychiatry.

Intermittent theta-burst stimulation combined with physical therapy as an optimal rehabilitation in Parkinson's disease: study protocol for a randomised, double-blind, controlled trial

BACKGROUND

First-line rehabilitative strategies to improve motor deficits are based on functional training (physical or occupational therapy), which has been demonstrated to facilitate neural reorganisation. Accumulating evidence suggests that non-invasive brain stimulation techniques, such as repetitive TMS (rTMS), may enhance neuroplasticity, thereby facilitating neural reorganisation and recovery from Parkinson's disease. Evidence also shows that intermittent theta-burst stimulation (iTBS) can improve motor function and quality of life in patients by promoting the excitability and neural remodelling of cerebral cortex. We aimed to combine iTBS stimulation with physiotherapy to improve the rehabilitation effect compared to physiotherapy alone in patients with Parkinson's disease.

METHODS

This randomised, double-blind clinical trial will enrol 50 Parkinson's disease patients aged 45-70 years with Hoehn and Yahr scale scores of 1-3. Patients are randomly assigned to either the iTBS + physiotherapy or sham-iTBS + physiotherapy group. The trial consists of a 2-week double-blind treatment period and a 24-week follow-up period. iTBS and sham-iTBS will be administered twice daily for 10 days based on physiotherapy. The primary outcome will be the third part of Movement Disorders-Unified Parkinson's Disease Rating Scale (MDS-UPDRS III) from the baseline to the first 2 days following completion hospitalised intervention. The secondary outcome will be 39-item Parkinson's Disease Questionnaire (PDQ-39) at 4 weeks, 12 weeks and 24 weeks after intervention. Tertiary outcomes are clinical evaluations and mechanism study outcomes such as NMSS, 6MWD, 10MT, TUG, BBS, MRI, and EEG, the length of time between the drug needs to be adjusted when symptoms fluctuate.

DISCUSSION

The aim of this study is to demonstrate that iTBS can promote overall function and quality of life in Parkinson's disease patients using physiotherapy and that this efficacy may be associated with altered neuroplasticity in exercise-related brain regions. The iTBS combined with physiotherapy training model will be evaluated during a 6-month follow-up period. With significant improvement in quality of life and motor function, iTBS combined with physiotherapy can be considered as a first-line rehabilitation option for Parkinson's disease. The potential of iTBS to enhance neuroplasticity in the brain should have a more positive impact in increasing the generality and efficiency of physiotherapy, improving the quality of life and overall functional status of patients with Parkinson's disease.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200056581. Registered on 8 February 2022.

Different synaptic mechanisms of intermittent and continuous theta-burst stimulations in a severe foot-shock induced and treatment-resistant depression in a rat model

Treatment-resistant depression (TRD) is a condition wherein patients with depression fail to respond to antidepressant trials. A new form of repetitive transcranial magnetic stimulation (rTMS), called theta-burst stimulation (TBS), which includes intermittent theta-burst stimulation (iTBS) and continuous theta-burst stimulation (cTBS), is non-inferior to rTMS in TRD treatment. However, the mechanism of iTBS and cTBS underlying the treatment of TRD in the prefrontal cortex (PFC) remains unclear. Hence, we applied foot-shock stress as a traumatic event to develop a TRD rat model and investigated the different mechanisms of iTBS and cTBS. The iTBS and cTBS treatment were effective in depressive-like behavior and active coping behavior. The iTBS treatments improved impaired long-term potentiation and long-term depression (LTD), whereas the cTBS treatment only improved aberrant LTD. Moreover, the decrease in mature brain-derived neurotrophic factor (BDNF)-related protein levels were reversed by iTBS treatment. The decrease in proBDNF-related protein expression was improved by iTBS and cTBS treatment. Both iTBS and cTBS improved the decreased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and downregulation of mammalian target of the rapamycin (mTOR) signaling pathway. The iTBS produces both excitatory and inhibitory synaptic effects, and the cTBS only produces inhibitory synaptic effects in the PFC.

The effect of repetitive transcranial magnetic stimulation on electroencephalography microstates of patients with heroin-addiction

The effects of transcranial magnetic stimulation in treating substance use disorders are gaining attention; however, most existing studies used subjective measures to examine the treatment effects. Objective electroencephalography (EEG)-based microstate analysis is important for measuring the efficacy of transcranial magnetic stimulation in patients with heroin addiction. We investigated dynamic brain activity changes in individuals with heroin addiction after transcranial magnetic stimulation using microstate indicators. Thirty-two patients received intermittent theta-burst stimulation (iTBS) over the left dorsolateral prefrontal cortex. Resting-state EEG data were collected pre-intervention and 10 days post-intervention. The feature values of the significantly different microstate classes were computed using a K-means clustering algorithm. Four EEG microstate classes (A-D) were noted. There were significant increases in the duration, occurrence, and contribution of microstate class A after the iTBS intervention. K-means classification accuracy reached 81.5%. The EEG microstate is an effective improvement indicator in patients with heroin addiction treated with iTBS. Microstates were examined using machine learning; this method effectively classified the pre- and post-intervention cohorts among patients with heroin addiction and healthy individuals. Using EEG microstate to measure heroin addiction and further exploring the effect of iTBS in patients with heroin addiction merit clinical investigation.

Feasibility of a combined intermittent theta-burst stimulation and video game-based dexterity training in Parkinson's disease

BACKGROUND

Persons with Parkinson's disease (PD) often exhibit difficulties with dexterity during the performance of activities of daily living (ADL), inter alia due to dysfunctional supplementary motor area (SMA). Combined intermittent theta-burst stimulation (iTBS) over the SMA followed by video game-based training (VBT) may therefore improve dexterity related ADL. The VBT may induce high flow levels related to high performance during the training. The aim of this study is to evaluate the feasibility of a combined iTBS-VBT intervention in persons with PD.

METHODS

A total of nine persons with PD (mean age 63.3 ± 8.76 years) with self-reported difficulties with dexterity related ADL were included in this pilot iTBS-VBT study. All participants received either iTBS or sham stimulation over the SMA followed by a 45-min VBT, three times a week for a total of three weeks. Feasibility was measured by means of the adherence rate and the system usability (System Usability Scale). Moreover, flow was measured after the last VBT session.

RESULTS

Adherence rate was excellent with 100%. High system usability scores (i.e., mean 80%, range 55-97.5) and a significant Spearman's correlation with the Flow State Scale (r = .762, p = .017) further point to the high feasibility of the VBT. Neither demographic variables nor difficulties in dexterity related ADL affected the usability of the VBT.

CONCLUSION

This study demonstrates the high feasibility of a combined iTBS-VBT intervention. Moreover, the level of self-reported usability was related to flow experience. Whether this kind of combined iTBS-VBT intervention improves dexterity will be evaluated in a randomized controlled trial. Trial registration clincaltrials.gov NCT04699149, date of registration 1. June 2021.

Influence of improved behavioral inhibition on decreased cue-induced craving in heroin use disorder: A preliminary intermittent theta burst stimulation study

BACKGROUND

Impaired behavioral inhibition is a critical factor in drug addiction and relapse. Repetitive transcranial magnetic stimulation (rTMS) reduces the craving of heroin-addicted individuals for drug-related cues. However, it is unclear whether this technique also improves impaired behavioral inhibition and how improved behavioral inhibition affects craving.

OBJECTIVE

The intermittent theta-burst stimulation (iTBS) has been recently shown to be non-inferior relative to rTMS for depression. Here, we aim to investigate the effect of iTBS on heroin-addicted individuals' behavioral inhibition and cue-induced craving and the relationship between the alteration of behavioral inhibition and craving.

METHOD

42 of 56 initially recruited individuals with the heroin-use disorder in the abstinent-course treatment were randomized to undergo active or sham iTBS to the left dorsolateral prefrontal cortex and received three daily iTBS treatments for 10 consecutive days. We measured participants' performance during a two-choice oddball task (80% standard and 20% deviant trials) and heroin-related cue-induced craving before and immediately after treatment.

RESULTS

The group that received active iTBS showed significantly improved two-choice oddball task performance after 10 days of intervention compared to both pre-intervention and the group who received sham iTBS. Similarly, a significant reduction in cue-induced craving was observed after following the intervention in the active iTBS group but not the sham iTBS group. The moderation model indicated that iTBS categories play a significant moderating role in the relationship between accuracy cost changing and altered cue-induced craving.

CONCLUSIONS

The iTBS treatment protocol positively affects behavioral inhibition in patients with heroin addiction. Improvements in behavioral inhibition can substantially reduce craving.

A systematic review and meta-analysis of the efficacy of intermittent theta burst stimulation (iTBS) on cognitive enhancement

Intermittent theta-burst stimulation (iTBS) has been used to focally regulate excitability of neural cortex over the past decade - however there is little consensus on the generalizability of effects reported in individual studies. Many studies use small sample sizes (N < 30), and there is a considerable amount of methodological heterogeneity in application of the stimulation itself. This systematic meta-analysis aims to consolidate the extant literature and determine if up-regulatory theta-burst stimulation reliably enhances cognition through measurable behavior. Results show that iTBS - when compared to suitable control conditions - may enhance cognition when outlier studies are removed, but also that there is a significant amount of heterogeneity across studies. Significant contributors to between-study heterogeneity include location of stimulation and method of navigation to the stimulation site. Surprisingly, the type of cognitive domain investigated was not a significant contributor of heterogeneity. The findings of this meta-analysis demonstrate that standardization of iTBS is urgent and necessary to determine if neuroenhancement of particular cognitive faculties are reliable and robust, and measurable through observable behavior.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Improving speech perception in noise in young and older adults using transcranial magnetic stimulation

Normal aging is associated with speech perception in noise (SPiN) difficulties. The objective of this study was to determine if SPiN performance can be enhanced by intermittent theta-burst stimulation (iTBS) in young and older adults.

METHOD

We developed a sub-lexical SPiN test to evaluate the contribution of age, hearing, and cognition to SPiN performance in young and older adults. iTBS was applied to the left posterior superior temporal sulcus (pSTS) and the left ventral premotor cortex (PMv) to examine its impact on SPiN performance.

RESULTS

Aging was associated with reduced SPiN accuracy. TMS-induced performance gain was greater after stimulation of the PMv compared to the pSTS. Participants with lower scores in the baseline condition improved the most.

DISCUSSION

SPiN difficulties can be reduced by enhancing activity within the left speech-processing network in adults. This study paves the way for the development of TMS-based interventions to reduce SPiN difficulties in adults.

Effects of repetitive Transcranial Magnetic Stimulation in aged rats depend on pre-treatment cognitive status: Toward individualized intervention for successful cognitive aging

BACKGROUND

Repetitive Transcranial Magnetic Stimulation (rTMS) has shown initial promise in combating age-related cognitive decline and dementia. The nature and severity of cognitive aging, however, varies markedly between individuals.

OBJECTIVE/HYPOTHESIS

We hypothesized that the distinct constellation of brain changes responsible for individual differences in cognitive aging might influence the response to rTMS.

METHODS

Cognitive effects of rTMS were evaluated using a rat model of cognitive aging in which aged rats are classified as Aged-Impaired (AI) or -Unimpaired (AU) relative to young (Y) according to their performance in the Morris water maze. Several weeks later, following presentation of a sample odor in an olfactory recognition task, rats received either sham (Y, n = 9; AU, n = 8; AI, n = 9) or intermittent Theta Burst Stimulation (Y, n = 8; AU, n = 8; AI, n = 9). Memory was tested 24 h later.

RESULTS

Recognition memory in the sham and stimulated conditions depended on pre-treatment cognitive status in the aged rats. Y and AU sham rats displayed robust odor recognition, whereas sham-treated AI rats exhibited no retention. In contrast, rTMS treated AI rats showed robust retention, comparable in magnitude to Y, whereas the AU stimulated scored at chance.

CONCLUSION

Our results are consistent with a perspective that the unique neurobiology associated with variability in cognitive aging modulates the response to rTMS. Protocols with documented efficacy in young adults may have unexpected outcomes in aging or neurodegenerative conditions, requiring individualized approaches.

Intermittent theta-burst stimulation moderates interaction between increment of N-Acetyl-Aspartate in anterior cingulate and improvement of unipolar depression

BACKGROUND

Intermittent theta-burst stimulation (iTBS), a novel repetitive transcranial magnetic stimulation (rTMS) technique, appears to have antidepressant effects when applied over left dorsolateral prefrontal cortex (DLPFC). However, its underlying neurobiological mechanisms are unclear. Proton magnetic resonance spectroscopy (¹H-MRS) provides in vivo measurements of cerebral metabolites altered in major depressive disorder (MDD) like N-acetyl-aspartate (NAA) and choline-containing compounds (Cho). We used MRS to analyse effects of iTBS on the associations between the shifts in the NAA and Cho levels during therapy and MDD improvement.

METHODS

In-patients with unipolar MDD (N = 57), in addition to treatment as usual, were randomized to receive 20 iTBS or sham stimulations applied over left DLPFC over four weeks. Single-voxel ¹H-MRS of the anterior cingulate cortex (ACC) was performed at baseline and follow-up. Increments of concentrations, as well as MDD improvement, were defined as endpoints. We tested a moderated mediation model of effects using the PROCESS macro (an observed variable ordinary least squares and logistic regression path analysis modeling tool) for SPSS.

RESULTS

Improvement of depressive symptoms was significantly associated with decrease of Cho/NAA ratio, mediated by NAA. iTBS had a significant moderating effect enhancing the relationship between NAA change and depression improvement.

CONCLUSIONS

Our findings suggest a potential neurochemical pathway and mechanisms of antidepressant action of iTBS, which may moderate the improvement of metabolic markers of neuronal viability. iTBS might increase neuroplasticity, thus facilitating normalization of neuronal circuit function.

Age-related differences in default-mode network connectivity in response to intermittent theta-burst stimulation and its relationships with maintained cognition and brain integrity in healthy aging

The default-mode network (DMN) is affected by advancing age, where particularly long-range connectivity has been consistently reported to be reduced as compared to young individuals. We examined whether there were any differences in the effects of intermittent theta-burst stimulation (iTBS) in DMN connectivity between younger and older adults, its associations with cognition and brain integrity, as well as with long-term cognitive status. Twenty-four younger and 27 cognitively normal older adults were randomly assigned to receive real or sham iTBS over the left inferior parietal lobule between two resting-state functional magnetic resonance imaging (rs-fMRI) acquisitions. Three years later, those older adults who had received real iTBS underwent a cognitive follow-up assessment. Among the younger adults, functional connectivity increased following iTBS in distal DMN areas from the stimulation site. In contrast, older adults exhibited increases in connectivity following iTBS in proximal DMN regions. Moreover, older adults with functional responses to iTBS resembling those of the younger participants exhibited greater brain integrity and higher cognitive performance at baseline and at the 3-year follow-up, along with less cognitive decline. Finally, we observed that 'young-like' functional responses to iTBS were also related to the educational background attained amongst older adults. The present study reveals that functional responses of the DMN to iTBS are modulated by age. Furthermore, combining iTBS and rs-fMRI in older adults may allow characterizing distinctive cognitive profiles in aging and its progression, probably reflecting network plasticity systems that may entail a neurobiological substrate of cognitive reserve.

Precise theta burst transcranial magnetic stimulation selectively reduced duration-related mismatch negativity

BACKGROUND

Mismatch negativity (MMN) is a typical event-related potential component reflecting pre-attentive processing. MMN impairment, especially reduced duration-related MMN (dMMN), has been suggested as a potential predictive biomarker for the onset of schizophrenia.

OBJECTIVE

This study attempts to manipulate specific MMN activities using advanced neuroimaging-guided intermittent theta-burst stimulations (iTBS), which will be helpful to uncover the sources of MMN generation and contribute to the development of new clinical treatments.

METHODS

Twenty-four healthy volunteers were recruited and participated two-session modulations consisting of active and sham iTBS. ITBS was precisely delivered over individual right posterior superior temporal cortex (pSTG). Before and after each iTBS session, two MMN components evoked by duration and frequency deviants were quantified respectively.

RESULTS

A significant interaction of time and iTBS was observed on dMMN amplitudes, but not frequency-related MMN amplitudes. dMMN only decreased after active precise iTBS intervention, but did not after sham iTBS. The post effect of iTBS on dMMN was found in 16 of 20 subjects, suggesting a robust effect even at individual level. Furthermore, sLORETA analysis showed that the lateralization of STG activation was reversed after the active iTBS.

CONCLUSIONS

We applied a precise strategy for neuroimaging-guided iTBS modulation over the right pSTG, which is promising in selectively modulating MMN for specific deviants.

Accelerated intermittent theta burst stimulation treatment in medication-resistant major depression: A fast road to remission?

Although accelerated repetitive Transcranial Magnetic Stimulation (rTMS) paradigms and intermittent Theta-burst Stimulation (iTBS) may have the potency to result in superior clinical outcomes in Treatment Resistant Depression (TRD), accelerated iTBS treatment has not yet been studied. In this registered randomized double-blind sham-controlled crossover study, spread over four successive days, 50 TRD patients received 20 iTBS sessions applied to the left dorsolateral prefrontal cortex (DLPFC). The accelerated iTBS treatment procedure was found to be safe and resulted in immediate statistically significant decreases in depressive symptoms regardless of order/type of stimulation (real/sham). While only 28% of the patients showed a 50% reduction of their initial Hamilton Depression Rating Scale score at the end of the two-week procedure, this response rate increased to 38% when assessed two weeks after the end of the sham-controlled iTBS protocol, indicating delayed clinical effects. Importantly, 30% of the responders were considered in clinical remission. We found no demographic predictors for response. Our findings indicate that only four days of accelerated iTBS treatment applied to the left DLPFC in TRD may lead to meaningful clinical responses within two weeks post stimulation.