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A systematic review of non-motor rTMS induced motor cortex plasticity.

Nordmann G, Azorina V, Langguth B, Schecklmann M - Front Hum Neurosci (2015)

Bottom Line: However, such studies revealed a high variability of both clinical and neuronal effects induced by rTMS.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).

View Article: PubMed Central - PubMed

Affiliation: Experimental and Clinical Neuroscience, University of Regensburg Regensburg, Germany ; Department of Psychiatry and Psychotherapy, University of Regensburg Regensburg, Germany.

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 re-adjusting the stimulation intensity according to the motor threshold over the course of the treatment.

No MeSH data available.


Related in: MedlinePlus

Positive findings of TMS-induced changes in non-motor areas with respect to motor cortex excitability. Please note that black, dark, and light gray represent different stimulation sites and white and black fonts represent healthy controls and patient groups, respectively. ↑, increases; ↔, no changes; ↓, decreases; CSP, cortical silent period; ICF, intracortical facilitation; MEP, motor evoked potential; RMT, resting motor threshold; SICI, short-interval intracortical inhibition; cTBS, continuous theta burst stimulation; iTBS, intermittent theta burst stimulation (8 s inter-burst interval); *22 out of 116 patients received combined frontal and temporal stimulation; **40% stimulator output instead of 100% RMT as stimulation intensity; ***90% active motor threshold over the inion instead of 80% RMT. Please note that increases in SICI means increases in inhibition and concomitantly a numeric decrease in the raw data.
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Figure 1: Positive findings of TMS-induced changes in non-motor areas with respect to motor cortex excitability. Please note that black, dark, and light gray represent different stimulation sites and white and black fonts represent healthy controls and patient groups, respectively. ↑, increases; ↔, no changes; ↓, decreases; CSP, cortical silent period; ICF, intracortical facilitation; MEP, motor evoked potential; RMT, resting motor threshold; SICI, short-interval intracortical inhibition; cTBS, continuous theta burst stimulation; iTBS, intermittent theta burst stimulation (8 s inter-burst interval); *22 out of 116 patients received combined frontal and temporal stimulation; **40% stimulator output instead of 100% RMT as stimulation intensity; ***90% active motor threshold over the inion instead of 80% RMT. Please note that increases in SICI means increases in inhibition and concomitantly a numeric decrease in the raw data.

Mentions: The search strategy yielded 29 articles in the publication period from 1999 to 2014. Methods and respective results of these studies are listed in Tables 2A–C. A summary of positive results is provided in Figure 1.


A systematic review of non-motor rTMS induced motor cortex plasticity.

Nordmann G, Azorina V, Langguth B, Schecklmann M - Front Hum Neurosci (2015)

Positive findings of TMS-induced changes in non-motor areas with respect to motor cortex excitability. Please note that black, dark, and light gray represent different stimulation sites and white and black fonts represent healthy controls and patient groups, respectively. ↑, increases; ↔, no changes; ↓, decreases; CSP, cortical silent period; ICF, intracortical facilitation; MEP, motor evoked potential; RMT, resting motor threshold; SICI, short-interval intracortical inhibition; cTBS, continuous theta burst stimulation; iTBS, intermittent theta burst stimulation (8 s inter-burst interval); *22 out of 116 patients received combined frontal and temporal stimulation; **40% stimulator output instead of 100% RMT as stimulation intensity; ***90% active motor threshold over the inion instead of 80% RMT. Please note that increases in SICI means increases in inhibition and concomitantly a numeric decrease in the raw data.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508515&req=5

Figure 1: Positive findings of TMS-induced changes in non-motor areas with respect to motor cortex excitability. Please note that black, dark, and light gray represent different stimulation sites and white and black fonts represent healthy controls and patient groups, respectively. ↑, increases; ↔, no changes; ↓, decreases; CSP, cortical silent period; ICF, intracortical facilitation; MEP, motor evoked potential; RMT, resting motor threshold; SICI, short-interval intracortical inhibition; cTBS, continuous theta burst stimulation; iTBS, intermittent theta burst stimulation (8 s inter-burst interval); *22 out of 116 patients received combined frontal and temporal stimulation; **40% stimulator output instead of 100% RMT as stimulation intensity; ***90% active motor threshold over the inion instead of 80% RMT. Please note that increases in SICI means increases in inhibition and concomitantly a numeric decrease in the raw data.
Mentions: The search strategy yielded 29 articles in the publication period from 1999 to 2014. Methods and respective results of these studies are listed in Tables 2A–C. A summary of positive results is provided in Figure 1.

Bottom Line: However, such studies revealed a high variability of both clinical and neuronal effects induced by rTMS.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).

View Article: PubMed Central - PubMed

Affiliation: Experimental and Clinical Neuroscience, University of Regensburg Regensburg, Germany ; Department of Psychiatry and Psychotherapy, University of Regensburg Regensburg, Germany.

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 re-adjusting the stimulation intensity according to the motor threshold over the course of the treatment.

No MeSH data available.


Related in: MedlinePlus