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Progress in Neuro-psychopharmacology &... Jun 2024Heart rate variability (HRV) is a useful tool for evaluating cardiovascular autonomic nervous system (ANS) functions. This systematic review and meta-analysis examined... (Review)
Review
BACKGROUND
Heart rate variability (HRV) is a useful tool for evaluating cardiovascular autonomic nervous system (ANS) functions. This systematic review and meta-analysis examined the potential effects of transcranial direct current stimulation (tDCS) protocols on HRV parameters.
METHODS
This study acquired 97 comparisons from 24 qualified studies for data synthesis. Using standardized mean difference (SMD), individual and overall effect sizes were estimated to show differences in HRV variables between active tDCS and sham stimulation conditions. More positive effect size values indicated that active tDCS caused greater increases in HRV than sham stimulation. Furthermore, moderator variable analyses were performed to determine whether changes in HRV variables differed depending on (a) task types (physical stress versus psychological stress versus resting condition), (b) targeted brain regions, (c) stimulation polarity, (d) characteristics of participants, and (e) specific HRV variables. Finally, we used meta-regression analyses to determine whether different tDCS parameters (i.e., the number of tDCS sessions, stimulation duration, and density) were associated with changes in HRV patterns.
RESULTS
The random-effects model meta-analysis showed that tDCS protocols significantly improved HRV variables (SMD = 0.400; P < 0.001). Moreover, for increasing HRV during the physical stress task (SMD = 1.352; P = 0.001), anodal stimulation on the M1 was effective, while combined polarity stimulation on the PFC improved HRV during the psychological stress task (SMD = 0.550; P < 0.001) and resting condition (SMD = 0.192; P = 0.012). Additional moderator variables and meta-regression analyses failed to show that tDCS protocols had positive effects in certain conditions, such as different stimulus polarity, characteristics of participants, specific HRV variables, and tDCS parameters.
CONCLUSION
These findings tentatively suggest that using tDCS protocols to stimulate optimal targeted brain areas may be effective in improving HRV patterns potentially related to cardiovascular ANS functions.
PubMed: 38925337
DOI: 10.1016/j.pnpbp.2024.111072 -
Journal of Neuroengineering and... Jun 2024Repeated transcranial magnetic stimulation (rTMS) could induce alterations in cortical excitability and promote neuroplasticity. To precisely quantify these effects,... (Meta-Analysis)
Meta-Analysis Review
Impact of repetitive transcranial magnetic stimulation on cortical activity: a systematic review and meta-analysis utilizing functional near-infrared spectroscopy evaluation.
BACKGROUND
Repeated transcranial magnetic stimulation (rTMS) could induce alterations in cortical excitability and promote neuroplasticity. To precisely quantify these effects, functional near-infrared spectroscopy (fNIRS), an optical neuroimaging modality adept at detecting changes in cortical hemodynamic responses, has been employed concurrently alongside rTMS to measure and tailor the impact of diverse rTMS protocols on the brain cortex.
OBJECTIVE
This systematic review and meta-analysis aimed to elucidate the effects of rTMS on cortical hemodynamic responses over the primary motor cortex (M1) as detected by fNIRS.
METHODS
Original articles that utilized rTMS to stimulate the M1 cortex in combination with fNIRS for the assessment of cortical activity were systematically searched across the PubMed, Embase, and Scopus databases. The search encompassed records from the inception of these databases up until April, 2024. The assessment for risk of bias was also conducted. A meta-analysis was also conducted in studies with extractable raw data.
RESULTS
Among 312 studies, 14 articles were eligible for qualitative review. 7 studies were eligible for meta-analysis. A variety of rTMS protocols was employed on M1 cortex. In inhibitory rTMS, multiple studies observed a reduction in the concentration of oxygenated hemoglobin [HbO] at the ipsilateral M1, contrasted by an elevation at the contralateral M1. Meta-analysis also corroborated this consistent trend. Nevertheless, certain investigations unveiled diminished [HbO] in bilateral M1. Several studies also depicted intricate inhibitory or excitatory interplay among distinct cortical regions.
CONCLUSION
Diverse rTMS protocols led to varied patterns of cortical activity detected by fNIRS. Meta-analysis revealed a trend of increasing [HbO] in the contralateral cortices and decreasing [HbO] in the ipsilateral cortices following low frequency inhibitory rTMS. However, due to the heterogeneity between studies, further research is necessary to comprehensively understand rTMS-induced alterations in brain activity.
Topics: Transcranial Magnetic Stimulation; Spectroscopy, Near-Infrared; Humans; Motor Cortex
PubMed: 38915003
DOI: 10.1186/s12984-024-01407-9 -
The International Journal of... Jun 2024Transcranial direct current stimulation (tDCS) has been used with increasing frequency as a therapeutic tool to alleviate clinical symptoms of obsessive... (Review)
Review
Transcranial direct current stimulation (tDCS) has been used with increasing frequency as a therapeutic tool to alleviate clinical symptoms of obsessive compulsive-disorder (OCD). However, little is known about the effects of tDCS on neurocognitive functioning among OCD patients. The aim of this review was to provide a comprehensive overview of the literature examining the effects of tDCS on specific neurocognitive functions in OCD. A literature search following PRISMA guidelines was conducted on the following databases: PubMed, PsycINFO, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Web of Science. The search yielded 4 results: one randomized, sham-controlled study (20 patients), one randomized, controlled, partial crossover trial (12 patients), one open-label study (5 patients), and one randomized, double-blind, sham-controlled, parallel-group trial (37 patients). A total of 51 patients received active tDCS with some diversity in electrode montages targeting the dorsolateral prefrontal cortex, the pre-supplementary motor area, or the orbitofrontal cortex. tDCS was associated with improved decision-making in study 1, enhanced attentional monitoring and response inhibition in study 2, improved executive and inhibitory control in study 3, and reduced attentional bias and improved response inhibition and working memory in study 4. Limitations of this review include its small sample, the absence of a sham group in half of the studies, and the heterogeneity in tDCS parameters. These preliminary results highlight the need for future testing in randomized, sham-controlled trials to examine whether and how tDCS induces relevant cognitive benefits in OCD.
PubMed: 38913323
DOI: 10.1080/00207454.2024.2371303 -
Brain Research Jun 2024Non-invasive brain stimulation induces changes in spontaneous neural activity in the cerebral cortex through facilitatory or inhibitory mechanisms, relying on... (Review)
Review
BACKGROUND
Non-invasive brain stimulation induces changes in spontaneous neural activity in the cerebral cortex through facilitatory or inhibitory mechanisms, relying on neuromodulation of neural excitability to impact brain plasticity. This systematic review assesses the state-of-the art and existing evidence regarding the effectiveness of NIBS in cognitive recovery among patients with chronic stroke.
MATERIALS AND METHODS
We conducted a systematic search, following PRISMA guidelines, for articles published from January 2010 through September 2023. We searched the following databases: PubMed, Embase, Cochrane Database of Systematic Reviews, PEDro, Rehab Data, and Web of Science.
RESULTS
Our electronic searches identified 109 papers. We assessed and included 61 studies based on their pertinence and relevance to the topic. After reading the full text of the selected publications and applying predefined inclusion criteria, we excluded 32 articles, leaving 28 articles for our qualitative analysis. We categorized our results into two sections as follows: (1) Cognitive and emotional domains (11 studies), (2) language and speech functions (16 studies).
CONCLUSION
Our findings highlight the potential of NIBS, such as tDCS and rTMS, in the cognitive, linguistic, and emotional recovery of post-stroke patients. Although it seems that NIBS may work as a complementary tool to enhance cognitive and communication abilities in patients with stroke -also in the chronic phase- evidence on behavioural outcomes is still poor. Future studies should focus on this important issue to confirm the effectiveness of neuromodulation in chronic neurological diseases. PROSPERO Registration: CRD42023458370.
PubMed: 38909976
DOI: 10.1016/j.brainres.2024.149093 -
World Neurosurgery Jun 2024One of the pressing constraints in the treatment for arteriovenous malformations (AVM) is the potential development of new neurological deficits, mainly when the AVM is... (Review)
Review
OBJECTIVE
One of the pressing constraints in the treatment for arteriovenous malformations (AVM) is the potential development of new neurological deficits, mainly when the AVM is in an eloquent area. The risk of ischemia when an "en passage" arterial supply is present is not negligible. In this regard, awake surgery holds promise in increasing the safety of low-grade AVMs resection.
METHODS
We conducted a pilot trial on 3 patients with low-grade AVMs affecting speech areas to evaluate the safety of awake craniotomy. Each feeder was temporarily clipped before the section. Also, we performed a systematic review to analyze the existing data about the impact of awake surgery in eloquent AVM resection.
RESULTS
None of the 3 patients presented with neurological deficits after the procedure. Awake craniotomy was useful in one case, as it allowed the detection of speech arrest during the temporal clipping of one of the feeders. This vessel was identified as an "en passage" vessel, closer to the nidus. The second attempt revealed the feeder of the AVM which was sectioned. Systematic review yielded 7 studies meeting our inclusion criteria. Twenty-six out of 33 patients included in these studies presented with AVM affecting speech area. Only 2 studies included the motor evoked potentials, 6 studies used direct cortical and subcortical stimulation. In all the studies asleep-awake-asleep (AAA) technique was used.
CONCLUSIONS
Awake craniotomies are safe procedures and may be helpful in avoiding ischemic complications in low-grade AVMs, either affecting eloquent areas and/or when "en passage" feeders are present.
PubMed: 38857871
DOI: 10.1016/j.wneu.2024.06.012 -
Neurosurgical Review May 2024Meningioma is the most common type of primary brain tumor which presents with a variety of neurological manifestations. Surgical resection tends to be the preferred... (Meta-Analysis)
Meta-Analysis Review
Meningioma is the most common type of primary brain tumor which presents with a variety of neurological manifestations. Surgical resection tends to be the preferred treatment. The occurrence of seizures after resection is common, which occur either early, within seven days of operation, or late. Our meta-analysis investigated the possible predictors of early and late postoperative seizures. We assessed the relevant observational studies on predictors of postoperative seizures published in PubMed, Scopus, and Web of Science from January 2000 to September 2022, and those that met inclusion criteria were included. We calculated the association between potential predicting factors and postoperative seizures, odds ratios (ORs) with 95% confidence intervals (CIs) applying either random or fixed-effect models. The early and late postoperative seizures were evaluated individually. Thirteen observational studies involving 4176 patients were included. Seizures occurred in 250 (6%) and 584 (14%) patients, respectively, in the early and late postoperative phases. Shared predictors for early and late seizures included tumors involving the motor cortex (OR = 2.7; 95% CI: 1.67-4.38, OR = 2.46; 95% CI: 1.68-3.61), postoperative neurological deficit (OR = 4.68; 95% CI: 2.67-8.22, OR = 2.01; 95% CI: 1.39-2.92), and preoperative seizures (OR = 2.52; 95% CI: 1.82-3.49, OR = 4.35; 95% CI: 3.29-5.75). Peritumoral edema (OR = 1.99; 95% CI: 1.49-2.64) was a significant factor only among late postoperative seizure patients while surgical complications (OR = 3.77; 95% CI: 2.39-5.93) was a significant factor solely for early postoperative seizures. Meningioma patients commonly experience early and late postoperative seizures. Identifying predictors of postoperative seizures is essential to diagnose and manage them effectively.
Topics: Meningioma; Humans; Seizures; Postoperative Complications; Meningeal Neoplasms; Neurosurgical Procedures
PubMed: 38806755
DOI: 10.1007/s10143-024-02487-w -
Reviews in the Neurosciences Apr 2024This systematic review aimed to evaluate the effects of different theta burst stimulation (TBS) protocols on improving upper extremity motor functions in patients with... (Review)
Review
This systematic review aimed to evaluate the effects of different theta burst stimulation (TBS) protocols on improving upper extremity motor functions in patients with stroke, their associated modulators of efficacy, and the underlying neural mechanisms. We conducted a meta-analytic review of 29 controlled trials published from January 1, 2000, to August 29, 2023, which investigated the effects of TBS on upper extremity motor, neurophysiological, and neuroimaging outcomes in poststroke patients. TBS significantly improved upper extremity motor impairment (Hedge's = 0.646, = 0.003) and functional activity (Hedge's = 0.500, < 0.001) compared to controls. Meta-regression revealed a significant relationship between the percentage of patients with subcortical stroke and the effect sizes of motor impairment ( = 0.015) and functional activity ( = 0.018). Subgroup analysis revealed a significant difference in the improvement of upper extremity motor impairment between studies using 600-pulse and 1200-pulse TBS ( = 0.002). Neurophysiological studies have consistently found that intermittent TBS increases ipsilesional corticomotor excitability. However, evidence to support the regional effects of continuous TBS, as well as the remote and network effects of TBS, is still mixed and relatively insufficient. In conclusion, TBS is effective in enhancing poststroke upper extremity motor function. Patients with preserved cortices may respond better to TBS. Novel TBS protocols with a higher dose may lead to superior efficacy compared with the conventional 600-pulse protocol. The mechanisms of poststroke recovery facilitated by TBS can be primarily attributed to the modulation of corticomotor excitability and is possibly caused by the recruitment of corticomotor networks connected to the ipsilesional motor cortex.
PubMed: 38671584
DOI: 10.1515/revneuro-2024-0030 -
Frontiers in Psychology 2024Exercise can induce brain plasticity. Functional near-infrared spectroscopy (fNIRS) is a functional neuroimaging technique that exploits cerebral hemodynamics and has...
Exercise can induce brain plasticity. Functional near-infrared spectroscopy (fNIRS) is a functional neuroimaging technique that exploits cerebral hemodynamics and has been widely used in the field of sports psychology to reveal the neural mechanisms underlying the effects of exercise. However, most existing fNIRS studies are cross-sectional and do not include exercise interventions. In addition, attributed to differences in experimental designs, the causal relationship between exercise and brain functions remains elusive. Hence, this systematic review aimed to determine the effects of exercise interventions on alterations in brain functional activity in healthy individuals using fNIRS and to determine the applicability of fNIRS in the research design of the effects of various exercise interventions on brain function. Scopus, Web of Science, PubMed, CNKI, Wanfang, and Weipu databases were searched for studies published up to June 15, 2021. This study was performed in accordance with the PRISMA guidelines. Two investigators independently selected articles and extracted relevant information. Disagreements were resolved by discussion with another author. Quality was assessed using the Cochrane risk-of-bias method. Data were pooled using random-effects models. A total of 29 studies were included in the analysis. Our results indicated that exercise interventions alter oxygenated hemoglobin levels in the prefrontal cortex and motor cortex, which are associated with improvements in higher cognitive functions (e.g., inhibitory control and working memory). The frontal cortex and motor cortex may be key regions for exercise-induced promotion of brain health. Future research is warranted on fluctuations in cerebral blood flow during exercise to elucidate the neural mechanism underlying the effects of exercise. Moreover, given that fNIRS is insensitive to motion, this technique is ideally suited for research during exercise interventions. Important factors include the study design, fNIRS device parameters, and exercise protocol. The examination of cerebral blood flow during exercise intervention is a future research direction that has the potential to identify cortical hemodynamic changes and elucidate the relationship between exercise and cognition. Future studies can combine multiple study designs to measure blood flow prior to and after exercise and during exercise in a more in-depth and comprehensive manner.
PubMed: 38659667
DOI: 10.3389/fpsyg.2024.1327822 -
Surgical Endoscopy Jun 2024Surgical skills acquisition is under continuous development due to the emergence of new technologies, and there is a need for assessment tools to develop along with... (Review)
Review
BACKGROUND
Surgical skills acquisition is under continuous development due to the emergence of new technologies, and there is a need for assessment tools to develop along with these. A range of neuroimaging modalities has been used to map the functional activation of brain networks while surgeons acquire novel surgical skills. These have been proposed as a method to provide a deeper understanding of surgical expertise and offer new possibilities for the personalized training of future surgeons. With studies differing in modalities, outcomes, and surgical skills there is a need for a systematic review of the evidence. This systematic review aims to summarize the current knowledge on the topic and evaluate the potential use of neuroimaging in surgical education.
METHODS
We conducted a systematic review of neuroimaging studies that mapped functional brain activation while surgeons with different levels of expertise learned and performed technical and non-technical surgical tasks. We included all studies published before July 1st, 2023, in MEDLINE, EMBASE and WEB OF SCIENCE.
RESULTS
38 task-based brain mapping studies were identified, consisting of randomized controlled trials, case-control studies, and observational cohort or cross-sectional studies. The studies employed a wide range of brain mapping modalities, including electroencephalography, functional magnetic resonance imaging, positron emission tomography, and functional near-infrared spectroscopy, activating brain areas involved in the execution and sensorimotor or cognitive control of surgical skills, especially the prefrontal cortex, supplementary motor area, and primary motor area, showing significant changes between novices and experts.
CONCLUSION
Functional neuroimaging can reveal how task-related brain activity reflects technical and non-technical surgical skills. The existing body of work highlights the potential of neuroimaging to link task-related brain activity patterns with the individual level of competency or improvement in performance after training surgical skills. More research is needed to establish its validity and usefulness as an assessment tool.
Topics: Humans; Clinical Competence; Neuroimaging; Brain; Brain Mapping; Magnetic Resonance Imaging; Positron-Emission Tomography; Electroencephalography
PubMed: 38653901
DOI: 10.1007/s00464-024-10830-x -
Frontiers in Aging Neuroscience 2024With aging, dual task (DT) ability declines and is more cognitively demanding than single tasks. Rapidly declining DT performance is regarded as a predictor of...
INTRODUCTION
With aging, dual task (DT) ability declines and is more cognitively demanding than single tasks. Rapidly declining DT performance is regarded as a predictor of neurodegenerative disease. Task training and non-invasive transcranial electrical stimulation (tES) are methods applied to optimize the DT ability of the elderly.
METHODS
A systematic search was carried out in the PUBMED, TDCS (transcranial direct current stimulation) databases, as well as Web of Science, and a qualitative analysis was conducted in 56 included studies. Aiming to summarize the results of studies that implemented tES, task training, or the combination for improving DT ability and related performance changes in healthy elderly and geriatric patients. For different approaches, the training procedures, parameters, as well as outcomes were discussed.
RESULTS
Task training, particularly cognitive-motor DT training, has more notable effects on improving DT performance in the elderly when compared to the neuromodulation method.
DISCUSSION
Anodal transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex (L-DLPFC), or its combination with task training could be promising tools. However, additional evidence is required from aged healthy people and patients, as well as further exploration of electrode montage.
PubMed: 38650865
DOI: 10.3389/fnagi.2024.1267307