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Fitzgerald PB, Fountain S, Daskalakis ZJ. A comprehensive review of the effects of rTMS on motor cortical excitability and inhibition. Clin Neurophysiol. 2006;117(12):2584-96

Alfred Psychiatry Research Centre, The Alfred and Monash University School of Psychiatry, Psychology and Psychological Medicine, Commercial Rd Melbourne, Vic. 3004, Australia. <>
Clinical Neurophysiology (Impact Factor: 2.98). 01/2007; 117(12):2584-96. DOI: 10.1016/j.clinph.2006.06.712
Source: PubMed

ABSTRACT Repetitive transcranial magnetic stimulation (rTMS) procedures are being widely applied in therapeutic and investigative studies. Numerous studies have investigated the effects of rTMS on cortical excitability and inhibition, yielding somewhat contradictory results. The purpose of this study was to comprehensively review this literature to guide the selection of methodology in therapeutic studies. We conducted a comprehensive review of all identified studies that investigated effects of low and/or high frequency rTMS on motor cortical excitability or inhibition. Low frequency rTMS appears to produce a transient reduction in cortical excitability as assessed by motor evoked potential (MEP) size and produces no substantial effect on cortical inhibition. High frequency rTMS appears to produce a persistent increase in MEP size and a reduction in cortical inhibition measured with paired pulse methods although few studies have investigated frequencies greater than 5Hz. A number of novel stimulation paradigms have significant potential for altering cortical excitability but require further investigation. Although commonly applied forms of rTMS have effects on cortical excitability, more substantial effects may be obtained through the use of novel stimulation paradigms or innovative approaches to the stimulation of areas connected to a potential target site. Further research is required, however, before these paradigms can be more widely adopted.

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    • "Typical measures are resting motor threshold (RMT), motor-evoked potentials (MEPs), shortinterval cortical inhibition (SICI), intracortical facilitation (ICF), and cortical silent period (CSP). Changes in cortical excitability pre vs. post rTMS are interpreted as measures of rTMS-induced changes in synaptic plasticity (Fitzgerald et al., 2006). In addition, motor cortex excitability measures have been investigated as potential markers for neuropsychiatric disease related factors (Radhu et al., 2013; Bunse et al., 2014). "
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    ABSTRACT: Motor cortex excitability can be measured by single-and paired-pulse transcranial magnetic stimulation (TMS). Repetitive transcranial magnetic stimulation (rTMS) can induce neuroplastic effects in stimulated and in functionally connected cortical regions. Due to its ability to non-invasively modulate cortical activity, rTMS has been investigated for the treatment of various neurological and psychiatric disorders. However, such studies revealed a high variability of both clinical and neuronal effects induced by rTMS. In order to better elucidate this meta-plasticity, rTMS-induced changes in motor cortex excitability have been monitored in various studies in a pre-post stimulation design. Here, we give a literature review of studies investigating motor cortex excitability changes as a neuronal marker for rTMS effects over non-motor cortical areas. A systematic literature review in April 2014 resulted in 29 articles in which motor cortex excitability was assessed before and after rTMS over non-motor areas. The majority of the studies focused on the stimulation of one of three separate cortical areas: the prefrontal area (17 studies), the cerebellum (8 studies), or the temporal cortex (3 studies). One study assessed the effects of multi-site rTMS. Most studies investigated healthy controls but some also stimulated patients with neuropsychiatric conditions (e.g., affective disorders, tinnitus). Methods and findings of the identified studies were highly variable showing no clear systematic pattern of interaction of non-motor rTMS with measures of motor cortex excitability. Based on the available literature, the measurement of motor cortex excitability changes before and after non-motor rTMS has only limited value in the investigation of rTMS related meta-plasticity as a neuronal state or as a trait marker for neuropsychiatric diseases. Our results do not suggest that there are systematic alterations of cortical excitability changes during rTMS treatment, which calls into question the practice of readjusting the stimulation intensity according to the motor threshold over the course of the treatment.
    Frontiers in Human Neuroscience 07/2015; 9. DOI:10.3389/fnhum.2015.00416 · 2.90 Impact Factor
    • "Non-invasive methods of brain stimulation such as transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) are extensively researched and are beginning to be used clinically to modulate brain activity (Paulus, 2003; Pascual-Leone et al., 2000; Hummel et al., 2005). Although these two methods have very different modes of action (rTMS stimulates axons in the brain and initiates new action potentials; tDCS polarises the neurones, and modulates their ongoing firing pattern) both of them, when applied over the motor cortex, produce changes in cortical excitability which, in the case of tDCS can last up to 90 min (Nitsche and Paulus, 2000, 2001; Fitzgerald et al., 2006). They also enhance motor performance and can change reaction times, movement accuracy and speed (Nitsche et al., 2003b; Kobayashi et al., 2004). "
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    ABSTRACT: To systematically review the methodology in particular treatment options and outcomes and the effect of multiple sessions of transcranial direct current stimulation (tDCS) with rehabilitation programmes for upper extremity recovery post stroke. A search was conducted for randomised controlled trials involving tDCS and rehabilitation for the upper extremity in stroke. Quality of included studies was analysed using the Modified Downs and Black form. The extent of, and effect of variation in treatment parameters such as anodal, cathodal and bi-hemispheric tDCS on upper extremity outcome measures of impairment and activity were analysed using meta-analysis. Nine studies (371 participants with acute, sub-acute and chronic stroke) were included. Different methodologies of tDCS and upper extremity intervention, outcome measures and timing of assessments were identified. Real tDCS combined with rehabilitation had a small non-significant effect of +0.11 (p=0.44) and +0.24 (p=0.11) on upper extremity impairments and activities at post-intervention respectively. Various tDCS methods have been used in stroke rehabilitation. The evidence so far is not statistically significant, but is suggestive of, at best, a small beneficial effect on upper extremity impairment. Future research should focus on which patients and rehabilitation programmes are likely to respond to different tDCS regimes. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
    Clinical Neurophysiology 05/2015; DOI:10.1016/j.clinph.2015.04.067 · 2.98 Impact Factor
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    • "rTMS focal magnetic pulses penetrate the skull to induce weak electrical currents that directly depolarize or hyperpolarize neuronal membranes. rTMS induced currents are sufficient to generate or inhibit action potentials (Pascual-Leone et al., 1998; Fitzgerald et al., 2006). An increasing number of studies have demonstrated that inhibitory low-frequency rTMS (≤1 Hz) over the unaffected hemisphere can be useful in aphasic patients. "
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    ABSTRACT: Chronic communication impairment is common after stroke, and conventional speech and language therapy (SLT) strategies have limited effectiveness in post-stroke aphasia. Neurorehabilitation with non-invasive brain stimulation techniques (NIBS)—particularly repetitive transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS)—may enhance the effects of SLT in selected patients. Applying inhibitory NIBS to specific homologous language regions may induce neural reorganization and reduce interhemispheric competition. This mini review highlights randomized controlled trials (RCTs) and randomized cross-over trials using low-frequency rTMS or cathodal tDCS over the non-lesioned non-language dominant hemisphere and performs an exploratory meta-analysis of those trials considered combinable. Using a random-effects model, a meta-analysis of nine eligible trials involving 215 participants showed a significant mean effect size of 0.51 (95% CI = 0.24–0.79) for the main outcome “accuracy of naming” in language assessment. No heterogeneity was observed (I2 = 0%). More multicenter RCTs with larger populations and homogenous intervention protocols are required to confirm these and the longer-term effects.
    Frontiers in Human Neuroscience 04/2015; 9(236). DOI:10.3389/fnhum.2015.00236 · 2.90 Impact Factor
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