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1.
Anodal transcranial direct current stimulation and intermittent theta-burst stimulation improve deglutition and swallowing reproducibility in elderly patients with dysphagia.
Cosentino, G, Tassorelli, C, Prunetti, P, Bertino, G, De Icco, R, Todisco, M, Di Marco, S, Brighina, F, Schindler, A, Rondanelli, M, et al
Neurogastroenterology and motility. 2020;(5):e13791
Abstract
BACKGROUND Dysphagia in the elderly, known as presbydysphagia, has become a relevant public health problem in several countries. Swallowing disorders may be a consequence of different neurological disorders (secondary presbydysphagia) or the expression of the aging process itself (primary presbydysphagia). We aimed to test the therapeutic potential of two different non-invasive brain stimulation (NIBS) techniques in subjects with primary or secondary presbydysphagia. METHODS A blinded randomized controlled trial with crossover design was carried out in 42 patients, randomly assigned to anodal transcranial direct current stimulation (tDCS) or intermittent theta-burst stimulation (TBS) group. Both tDCS and TBS were applied for 5 consecutive days over the right swallowing motor cortex. The swallowing function was assessed before and 1 and 3 months after the stimulation using the Dysphagia Outcome and Severity Scale (DOSS), scored based on clinical assessment and fiberoptic endoscopic evaluation of swallowing. An electrophysiological method was also applied to evaluate changes in the reproducibility of the swallowing behavior. KEY RESULTS Both real tDCS and TBS had beneficial effects on the swallowing function in patients with primary and secondary presbydysphagia. Anodal tDCS resulted in an improvement of 0.5 points in DOSS at 1-month follow-up (P = .014), whereas intermittent TBS induced an increase of 0.7 and 0.6 points at 1- and 3-month follow-up evaluations, respectively (P = .0001 and P = .005, respectively). Reproducibility of both the oral and pharyngeal phases of swallowing significantly increased at 1-month follow-up. CONCLUSIONS AND INFERENCES Our results suggest that non-invasive cortical stimulation may be useful for dysphagia recovery in elderly patients.
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2.
Effects of Transcranial Direct Current Stimulation (tDCS) and Approach Bias Modification (ABM) training on food cravings in people taking antipsychotic medication.
Grycuk, L, Gordon, G, Gaughran, F, Campbell, IC, Schmidt, U
Trials. 2020;(1):245
Abstract
BACKGROUND Antipsychotic drug-induced weight gain puts individuals with schizophrenia at increased cardiometabolic risk. As a potential intervention for this problem, we describe the theoretical background and a protocol for a feasibility randomised controlled trial (RCT) of approach bias modification (ABM) training combined with real versus sham (placebo) transcranial direct current stimulation (tDCS). The primary aim of this trial is to obtain information that will guide decision making and protocol development in relation to a future large-scale RCT of ABM and tDCS in this group of participants. Second, the study will assess the preliminary efficacy of ABM + tDCS in reducing food cravings in people who take antipsychotic medication. METHODS Thirty adults with a DSM-V diagnosis of schizophrenia or schizoaffective disorder treated with anti-psychotic medication will be randomly allocated to receive five sessions that will combine ABM and real or sham tDCS, in a parallel group design. In this feasibility study, a broad range of outcome variables will be examined. Measures will include food craving, psychopathology (e.g. symptoms of schizophrenia and depression), neuropsychological processes (such as attentional bias and impulsiveness), and the tolerability and acceptability of tDCS. The feasibility of conducting a large-scale RCT of ABM + tDCS and appropriateness of tDCS as a treatment for antipsychotic drug-induced weight gain will be evaluated by assessment of recruitment and retention rates, acceptability of random allocation, blinding success (allocation concealment), completion of treatment sessions and research assessments (baseline, post-treatment and follow-up). DISCUSSION The effect sizes generated and other findings from this trial will inform a future large-scale RCT with respect to decisions on primary outcome measures and other aspects of protocol development. In addition, results from this study will provide a preliminary indication of the efficacy of ABM + tDCS treatment for antipsychotic drug-induced weight gain. TRIAL REGISTRATION ISRCTN Registry, ISRCTN13280178. Registered on 16 October 2018.
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3.
Determination of anodal tDCS duration threshold for reversal of corticospinal excitability: An investigation for induction of counter-regulatory mechanisms.
Hassanzahraee, M, Nitsche, MA, Zoghi, M, Jaberzadeh, S
Brain stimulation. 2020;(3):832-839
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) is used to induce neuroplasticity in the human brain. Within certain limits of stimulation duration, anodal tDCS (a-tDCS) over the primary motor cortex induces long term potentiation- (LTP) like plasticity. A reversal of the direction of plasticity has however been described with prolonged a-tDCS protocols. OBJECTIVE We aimed to systematically investigate the intervention duration threshold for reversal of a-tDCS-induced effects on corticospinal excitability (CSE) and to determine the probable mechanisms involved in these changes. METHODS Fifteen healthy participants received a-tDCS of 1 mA for five different durations in pseudo-random session order. Transcranial magnetic stimulation (TMS) was delivered over the left M1, and motor evoked potentials (MEPs) of a contralateral hand muscle were recorded before, immediately and 30 min following intervention to measure CSE changes. Short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), and long interval facilitation (LIF) were assessed via paired-pulse TMS protocols. RESULTS A-tDCS significantly increased CSE as expected at stimulation durations of 22 and 24 min. However, this effect of a-tDCS on CSE decreased and even reversed when stimulation duration increased to 26, 28, and 30 min. Respective alterations of ICF, LIF, and SICI indicate the involvement of glutamatergic, and GABAergic systems in these effects. CONCLUSIONS These results confirm a duration threshold for reversal of the excitability-enhancing effect of a-tDCS with stimulation durations ≥ 26 min. Counter-regulatory mechanisms are discussed as a mechanistic foundation for these effects, which might prevent excessive brain activation.
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4.
Comparing the effects of multi-session anodal trans-cranial direct current stimulation of primary motor and dorsolateral prefrontal cortices on fatigue and quality of life in patients with multiple sclerosis: a double-blind, randomized, sham-controlled trial.
Mortezanejad, M, Ehsani, F, Masoudian, N, Zoghi, M, Jaberzadeh, S
Clinical rehabilitation. 2020;(8):1103-1111
Abstract
OBJECTIVE To compare the effects of anodal trans-cranial direct current stimulation (a-tDCS) over primary motor and dorsolateral prefrontal cortices on Fatigue Severity Scale and its lasting effect on fatigue reduction and improvement in quality of life in patients with multiple sclerosis. DESIGN A randomized, double-blinded, sham-controlled parallel clinical trial study. SETTING Neurological physiotherapy clinics. SUBJECTS Thirty-nine participants were randomly assigned to three groups: dorsolateral prefrontal cortex a-tDCS, primary motor a-tDCS (experimental groups) and sham a-tDCS. Finally, 36 participants completed the whole study (n = 12 in each group). INTERVENTIONS Participants in the experimental groups received six-session a-tDCS (1.5 mA, 20 minutes) during two weeks (three sessions per week). The sham group received six sessions of 20-minute sham stimulation. MAIN MEASURES The Fatigue Severity Scale and quality of life were assessed before, immediately and four weeks after the intervention. RESULTS Findings indicated a significant reduction in the Fatigue Severity Scale and a significant increase in the quality of life in both experimental groups, immediately after the intervention (P < 0.001), while Fatigue Severity Scale and quality of life changes were not significant in the sham a-tDCS group (P > 0.05). In addition, improvement of the variables remained four weeks after the intervention in dorsolateral prefrontal cortex a-tDCS (mean differences (95% confidence interval): 0.03 (-0.63 to 0.68) as compared to primary motor (-0.62 (-0.11 to -1.14) and sham a-tDCS groups (-0.47 (-1.37 to 0.43)). CONCLUSION Both primary motor and dorsolateral prefrontal cortex a-tDCS as compared to sham intervention can immediately improve fatigue and quality of life. However, the effects last up to four weeks only by the dorsolateral prefrontal cortex a-tDCS.
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5.
Prefrontal Cortex Neuromodulation Enhances Frontal Asymmetry and Reduces Caloric Intake in Patients with Morbid Obesity.
Forcano, L, Castellano, M, Cuenca-Royo, A, Goday-Arno, A, Pastor, A, Langohr, K, Castañer, O, Pérez-Vega, KA, Serra, C, Ruffini, G, et al
Obesity (Silver Spring, Md.). 2020;(4):696-705
Abstract
OBJECTIVE The objective of this study was to test the feasibility of a combined intervention involving transcranial direct current stimulation (tDCS) on the dorsolateral prefrontal cortex (dlPFC) and cognitive training (CT). Short-term effects on food consumption, cognition, endocannabinoid (eCB) levels, and electroencephalogram (EEG) markers of future weight loss were explored. METHODS Eighteen healthy volunteers with morbid obesity were randomized in a double-blind, placebo-controlled, parallel trial. Participants received sham or active tDCS plus CT for four consecutive days. Cognitive performance, daily food intake, and eCB blood samples were collected before and after the intervention; EEG data were gathered before and after daily training. RESULTS The active tDCS + CT group reversed left-dominant frontal asymmetry and increased frontal coherence (FC) in the γ-band (30-45 Hz) after the intervention. The strength of the latter predicted BMI reduction. Additionally, a large intervention effect on food intake was shown in the active tDCS + CT group at follow-up (-339.6 ± 639 kcal on average), and there was a decrease of plasma eCB concentrations. CONCLUSIONS dlPFC modulation through tDCS + CT is an effective tool to restore right dominance of the dlPFC and enhance FC in patients with morbid obesity. Moreover, the effect of the strength of FC on BMI suggests that the interhemispheric FC at the dlPFC is functionally relevant for the efficient regulation of food choice.
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6.
The effects of trans-cranial direct current stimulation intervention on fear: A systematic review of literature.
Yosephi, MH, Ehsani, F, Daghiani, M, Zoghi, M, Jaberzadeh, S
Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia. 2019;:7-13
Abstract
Intensifying fear and fear of pain may lead to some diseases such as panic disorder, phobias, post-traumatic stress disorder (PTSD), anxiety disorders, depression, etc. A number of studies indicated positive effect of transcranial direct current stimulation (tDCS) on controlling fear and some studies did not observe any effect or even negative effect on decreasing fear. Due to lack of consensus in the findings of research, we aimed to systematically review studies, which investigated the effect of tDCS on fear. A literature search was conducted using the databases of PubMed, Science Direct, OVID, CINAHL, PEDro, Cochrane, Scopus and MEDLINE. Fear, fear memory, fear of pain, anxiety, post-traumatic stress disorder, electrical brain stimulation were applied as keywords. The valid assessment scale was used to evaluate the methodological quality of the included studies. The results of this systematic review revealed that the cathodal tDCS (c-tDCS) on the left dorsolateral prefrontal cortex (DLPFC) as compared to anodal tDCS (a-tDCS) could significantly reduce fear and modulate the fear memory. In addition, the findings of this study showed that the c-tDCS has positive effect on behavioural parameters of fear, while it cannot change biochemical parameters of fear during limited sessions of intervention. Application of c-tDCS on the left DLPFC could significantly reduce fear and modulate the fear memory.
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7.
Appetite effects of prefrontal stimulation depend on COMT Val158Met polymorphism: A randomized clinical trial.
Fassini, PG, Das, SK, Suen, VMM, Magerowski, G, Marchini, JS, da Silva Junior, WA, Changyu, S, Alonso-Alonso, M
Appetite. 2019;:142-150
Abstract
The regulation of appetite is supported by dopamine-modulated brain circuits. Recent studies have shown that transcranial direct current stimulation (tDCS) aimed at increasing the excitability of the dorsolateral prefrontal cortex can reduce appetite, but the underlying mechanisms remain unknown, and response variability is large. The aim of this study was to determine whether individual differences in Catechol-O-methyl transferase (COMT) Val158Met polymorphism can influence tDCS effects on appetite. Thirty-eight adult women with obesity, classified as carriers or non-carriers of the Met allele, underwent a randomized, double-blind, sham-controlled tDCS intervention involving three phases: Phase I, target engagement (immediate effects of tDCS on working memory performance), Phase II, tDCS only (10 sessions, two weeks), and Phase III, tDCS + hypocaloric diet: (6 sessions, two weeks, 30% energy intake reduction, inpatient). Data were analyzed using linear mixed-effects models and mixed ANCOVA. Appetite was evaluated using visual analogue scales. We found that Met-carriers receiving active tDCS were the only participants who experienced a significant reduction of appetite over time. Conversely, Met non-carriers maintained high levels of appetite during the intervention; this effect was driven by a delayed paradoxical rise in appetite after stimulation. Working memory task performance at phase I correlated with subsequent appetite change in a COMT-dependent manner: speed improvements during the task predicted appetite increase in Met carriers and appetite reduction in Met non-carriers. Our findings suggest that genotype differences impacting dopamine levels influence prefrontal tDCS effects on appetite. This source of variability should be considered in the design of future studies.
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8.
1H MR spectroscopy of the motor cortex immediately following transcranial direct current stimulation at 7 Tesla.
Ryan, K, Wawrzyn, K, Gati, JS, Chronik, BA, Wong, D, Duggal, N, Bartha, R
PloS one. 2018;(8):e0198053
Abstract
Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that may modulate cortical excitability, metabolite concentration, and human behaviour. The supplementary motor area (SMA) has been largely ignored as a potential target for tDCS neurorehabilitation but is an important region in motor compensation after brain injury with strong efferent connections to the primary motor cortex (M1). The objective of this work was to measure tissue metabolite changes in the human motor cortex immediately following tDCS. We hypothesized that bihemispheric tDCS would change levels of metabolites involved in neuromodulation including N-acetylaspartate (NAA), glutamate (Glu), and creatine (tCr). In this single-blind, randomized, cross-over study, fifteen healthy adults aged 21-60 participated in two 7T MRI sessions, to identify changes in metabolite concentrations by magnetic resonance spectroscopy. Immediately after 20 minutes of tDCS, there were no significant changes in metabolite levels or metabolite ratios comparing tDCS to sham. However there was a trend toward increased NAA/tCr concentration (p = 0.08) in M1 under the stimulating cathode. There was a strong, positive correlation between the change in the absolute concentration of NAA and the change in the absolute concentration of tCr (p<0.001) suggesting an effect of tDCS. Both NAA and creatine are important markers of neurometabolism. Our findings provide novel insight into the modulation of neural metabolites in the motor cortex immediately following application of bihemispheric tDCS.
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9.
Concurrent exergaming and transcranial direct current stimulation to improve balance in people with Parkinson's disease: study protocol for a randomised controlled trial.
Harris, DM, Rantalainen, T, Muthalib, M, Johnson, L, Duckham, RL, Smith, ST, Daly, RM, Teo, WP
Trials. 2018;(1):387
Abstract
BACKGROUND People with Parkinson's disease (PD) commonly experience postural instability, resulting in poor balance and an increased risk of falls. Exercise-based video gaming (exergaming) is a form of physical training that is delivered through virtual reality technology to facilitate motor learning and is efficacious in improving balance in aged populations. In addition, studies have shown that anodal transcranial direct current stimulation (a-tDCS), when applied to the primary motor cortex, can augment motor learning when combined with physical training. However, no studies have investigated the combined effects of exergaming and tDCS on balance in people with PD. METHODS/DESIGN Twenty-four people with mild to moderate PD (Hoehn and Yahr scale score 2-4) will be randomly allocated to receive one of three interventions: (1) exergaming + a-tDCS, (2) exergaming + sham a-tDCS or (3) usual care. Participants in each exergaming group will perform two training sessions per week for 12 weeks. Each exergaming session will consist of a series of static and dynamic balance exercises using a rehabilitation-specific software programme (Jintronix) and 20 minutes of either sham or real a-tDCS (2 mA) delivered concurrently. Participants allocated to usual care will be asked to maintain their normal daily physical activities. All outcome measures will be assessed at baseline and at 6 weeks (mid-intervention), 12 weeks (post-intervention) and 24 weeks (3-month follow-up) after baseline. The primary outcome measure will be the Limits of Stability Test. Secondary outcomes will include measures of static balance, leg strength, functional capacity, cognitive task-related cortical activation, corticospinal excitability and inhibition, and cognitive inhibition. DISCUSSION This will be the first trial to target balance in people with PD with combined exergaming and a-tDCS. We hypothesise that improvements in balance, functional and neurophysiological outcome measures, and neurocognitive outcome measures will be greater and longer-lasting following concurrent exergaming and a-tDCS than in those receiving sham tDCS or usual care. TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry, ACTRN12616000594426 ). Registered on 9 May 2016.
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10.
Anodal tDCS of the swallowing motor cortex for treatment of dysphagia in multiple sclerosis: a pilot open-label study.
Cosentino, G, Gargano, R, Bonura, G, Realmuto, S, Tocco, E, Ragonese, P, Gangitano, M, Alfonsi, E, Fierro, B, Brighina, F, et al
Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology. 2018;(8):1471-1473
Abstract
Swallowing difficulties are a common symptom of multiple sclerosis (MS). The early detection and treatment of dysphagia is critical to prevent complications, including poor nutrition, dehydration, and lung infections. Recently, transcranial direct current stimulation (tDCS) has been proven to be effective in ameliorating swallowing problems in stroke patients. In this pilot study, we aimed to assess safety and efficacy of transcranial direct current stimulation (tDCS) in the treatment of dysphagia in MS patients. We screened 30 patients by using the 10-item DYsphagia in MUltiple Sclerosis (DYMUS) questionnaire, and patients at risk for dysphagia underwent a clinical and fiberoptic endoscopic evaluation of swallowing (FEES). Six patients who presented with mild to moderate dysphagia underwent the experimental procedures. These consisted of 5 sessions of anodal tDCS applied in consecutive days over the right swallowing motor cortex. Patients were followed-up at 1 week, 1 month and 3 months after treatment, and changes in the Dysphagia Outcome and Severity Scale (DOSS) score between baseline and post-tDCS were assessed. Our results showed that in all patients, the tDCS treatment determined a mild but significant clinical benefit (one-point improvement in the DOSS score) lasting up to 1 month. In conclusion, our preliminary results show that anodal tDCS has therapeutic potential in the treatment of swallowing problems in patients suffering with MS. However, future double-blind, randomized, and sham-controlled studies are needed to confirm the present findings.