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brain-stimulation:rtms [on July 11, 2017] |
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| + | ====== Repetitive Transcranial Magnetic Stimulation (rTMS) ====== | ||
| + | {{INLINETOC}} | ||
| + | ===== Primer ===== | ||
| + | <WRAP group> | ||
| + | <WRAP half column> | ||
| + | **Repetitive Transcranial Magnetic Stimulation (rTMS)** is a form of [[brain-stimulation:home|brain stimulation]] that uses focused magnetic field pulses to induce electrical currents in neural tissue non-invasively, via an inductor coil positioned against the scalp. | ||
| + | </WRAP> | ||
| + | <WRAP half column> | ||
| + | <catlist brain-stimulation:: -columns:1 -noAddPageButton -sortAscending -noNSInBold> | ||
| + | </WRAP> | ||
| + | </WRAP> | ||
| + | ===== Mechanism of Action ===== | ||
| + | * rTMs is thought to work by altering neurotransmitter transmission, neuronal electrophysiology, blood flow, brain activity in a frequency-dependent manner.[([[https://pubmed.ncbi.nlm.nih.gov/26349810/|Noda, Y., Silverstein, W. K., Barr, M. S., Vila-Rodriguez, F., Downar, J., Rajji, T. K., ... & Blumberger, D. M. (2015). Neurobiological mechanisms of repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex in depression: a systematic review. Psychological medicine, 45(16), 3411.]])] | ||
| + | |||
| + | ===== Delivery Parameters ===== | ||
| + | * rTMS parameters include adjusting the stimulation intensity, frequency, pattern, and site | ||
| + | * Conventional figure-8 or circular rTMS coils can target brain regions 1 to 4 cm deep to the scalp, while helmet-shaped "deep" rTMS coils can stimulate slightly deeper structures. | ||
| + | * For determining coil placement, [[neurology:mri|magnetic resonance imaging]] (MRI) guidance is the most precise method. But in clinical reality, scalp-based navigation is most common. | ||
| + | * The stimulus intensity is based on individually determined resting motor threshold (RMT), which is the //minimum// intensity needed to elicit muscle twitches at relaxed upper or lower extremities, by visual inspection or electromyography (EMG) assessment | ||
| + | * The most common intensity in all trials to date is between 110% to 120% RMT.[([[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4994792/|Milev, R. V., Giacobbe, P., Kennedy, S. H., Blumberger, D. M., Daskalakis, Z. J., Downar, J., ... & CANMAT Depression Work Group. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 4. Neurostimulation treatments. The Canadian Journal of Psychiatry, 61(9), 561-575.]])] | ||
| + | * Stimulation above these levels are outside conventional safety guidelines. | ||
| + | * Newer theta-burst stimulation (TBS) protocols are more commonly delivered at lower intensities (e.g. - 70%-80% active motor threshold).[([[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4994792/|Milev, R. V., Giacobbe, P., Kennedy, S. H., Blumberger, D. M., Daskalakis, Z. J., Downar, J., ... & CANMAT Depression Work Group. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 4. Neurostimulation treatments. The Canadian Journal of Psychiatry, 61(9), 561-575.]])] | ||
| + | * TBS protocols require only 1 to 3 minutes of stimulation and may achieve comparable or stronger effects. | ||
| + | * Intermittent TBS (iTBS) is considered excitatory and continuous TBS (cTBS) inhibitory. | ||
| + | * Different stimulation frequency and patterns also exert different effects | ||
| + | * Conventionally, high-frequency rTMS (5 to 20 Hz) is considered excitatory, while low-frequency stimulation (1 to 5 Hz) is inhibitory. | ||
| + | * Conventional stimulation is delivered in 2 to 10-second trains at 10- to 60-second intervals, in 15 to 45-minute sessions. | ||
| + | <WRAP group> | ||
| + | <WRAP half column> | ||
| + | <panel type="info" title="rTMS Treatment Parameters" subtitle="Milev, R. V. et al. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 4. Neurostimulation treatments. The Canadian Journal of Psychiatry, 61(9), 561-575." no-body="true" footer=""> | ||
| + | ^ Intensity, frequency, and site | • Stimulate at 110%-120% of resting motor threshold (70%-80% for theta-burst stimulation)\\ • Select stimulation frequency and site | | ||
| + | ^ Treatment course | • Perform stimulation 5 times weekly (Level 1)\\ • Deliver initial course until symptom remission is achieved, up to 20 sessions (4 weeks) (Level 1)\\ • Extend course to 30 sessions (6 weeks) in responders who have not achieved symptom remission (Level 3) | | ||
| + | ^ Maintenance course | • Use rTMS as needed to maintain response (Level 3) | | ||
| + | </panel> | ||
| + | |||
| + | </WRAP> | ||
| + | <WRAP half column> | ||
| + | <panel type="info" title="Recommendation for rTMS Stimulation Protocols" subtitle="Milev, R. V. et al. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 4. Neurostimulation treatments. The Canadian Journal of Psychiatry, 61(9), 561-575." no-body="true" footer="DLPFC = dorsolateral prefrontal cortex; DMPFC = dorsomedial prefrontal cortex; rTMS = repetitive transcranial magnetic stimulation; TBS = theta-burst stimulation."> | ||
| + | ^ First line | • High-frequency rTMS to left DLPFC\\ • Low-frequency rTMS to right DLPFC | | ||
| + | ^ Second line | • Bilateral rTMS to DLPFC (left high-frequency and right low-frequency) (Level 1)\\ • Low-frequency rTMS to right DLPFC (in non-responders to high-frequency left DLPFC-rTMS), OR high-frequency rTMS to left DLPFC (in non-responders to low-frequency right DLPFC-rTMS) (Level 1)\\ \\ TBS protocols (Level 3):\\ • Intermittent TBS to left DLPFC \\ • Left intermittent and right continuous TBS to DLPFC \\ • Intermittent TBS to bilateral DMPFC | | ||
| + | ^ Third line | • High-frequency rTMS to bilateral DMPFC (Level 3) | | ||
| + | </panel> | ||
| + | </WRAP> | ||
| + | </WRAP> | ||
| + | |||
| + | ===== Number of Treatments ===== | ||
| + | * Standard protocols deliver rTMS once daily, for 5 days of the week | ||
| + | * 3-times-per-week rTMS has also been reported as similarly effective, but with slower improvement and a similar number of sessions required overall. | ||
| + | * Studies have found peak effects at 26 to 28 sessions of rTMS.[([[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4994792/|Milev, R. V., Giacobbe, P., Kennedy, S. H., Blumberger, D. M., Daskalakis, Z. J., Downar, J., ... & CANMAT Depression Work Group. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 4. Neurostimulation treatments. The Canadian Journal of Psychiatry, 61(9), 561-575.]])] | ||
| + | * Thus, at least ''20'' sessions (i.e. - 4 weeks) should be attempted before declaring treatment failure, with extension to 25 to 30 sessions if improvements occur. | ||
| + | |||
| + | ===== Effectiveness ===== | ||
| + | <alert type="info" icon="fa fa-book fa-lg fa-fw"> | ||
| + | See also: **[[https://pubmed.ncbi.nlm.nih.gov/33955792/|Malhi, G. S. et al. (2021). Is rTMS Ready for Primetime?. The Canadian Journal of Psychiatry.]]** | ||
| + | </alert> | ||
| + | |||
| + | * Repeated rTMS sessions can exert therapeutic effects that last several months. | ||
| + | * Most rTMS studies are on patients with some degree of treatment resistant depression (i.e. - failed at least 1 or 2 antidepressant trials) | ||
| + | * rTMS is considered a first-line treatment for MDD for patients who have failed at least 1 antidepressant treatment) | ||
| + | * Unfortunately, without maintenance treatment, relapse is common following successful rTMS treatment.[([[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4994792/|Milev, R. V., Giacobbe, P., Kennedy, S. H., Blumberger, D. M., Daskalakis, Z. J., Downar, J., ... & CANMAT Depression Work Group. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 4. Neurostimulation treatments. The Canadian Journal of Psychiatry, 61(9), 561-575.]])] | ||
| + | * One study had a median relapse by 120 days (and relapse rates of 25%, 40%, 57%, and 77% at 2, 3, 4, and 6 months).[([[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4994792/|Milev, R. V., Giacobbe, P., Kennedy, S. H., Blumberger, D. M., Daskalakis, Z. J., Downar, J., ... & CANMAT Depression Work Group. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 4. Neurostimulation treatments. The Canadian Journal of Psychiatry, 61(9), 561-575.]])] | ||
| + | * There remains insufficient evidence to support any one schedule of rTMS maintenance sessions over another. | ||
| + | * rTMS is remains less effective than [[brain-stimulation:ect|electroconvulsive therapy]] (ECT), especially for patients with symptoms of psychosis. | ||
| + | * Additionally, rTMS response rates are worse in patients who have also failed ECT.[([[https://pubmed.ncbi.nlm.nih.gov/24388670/|Downar, J., Geraci, J., Salomons, T. V., Dunlop, K., Wheeler, S., McAndrews, M. P., ... & Giacobbe, P. (2014). Anhedonia and reward-circuit connectivity distinguish nonresponders from responders to dorsomedial prefrontal repetitive transcranial magnetic stimulation in major depression. Biological psychiatry, 76(3), 176-185.]])] | ||
| + | |||
| + | ===== Contraindications ===== | ||
| + | ==== Absolute ==== | ||
| + | * The only contraindication to rTMS is if an individual has metallic hardware (e.g. - cochlear implants, brain stimulators or electrodes, aneurysm clips) anywhere in their head, except the mouth. | ||
| + | |||
| + | ==== Relative ==== | ||
| + | * Cardiac pacemaker, implantable defibrillator, a history of epilepsy, or the presence of a brain lesion (vascular, traumatic, neoplastic, infectious, or metabolic). | ||
| + | * A history of seizures or epilepsy are a //relative// contraindication to rTMS[([[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4670017/|Dobek, C. E., Blumberger, D. M., Downar, J., Daskalakis, Z. J., & Vila-Rodriguez, F. (2015). Risk of seizures in transcranial magnetic stimulation: a clinical review to inform consent process focused on bupropion. Neuropsychiatric Disease and Treatment, 11, 2975.]])] | ||
| + | * To date, less than 25 cases of rTMS-induced seizure have been reported worldwide (in terms of numbers, rTMS has a ∼0.01% to 0.1% incidence, versus 0.1% to 0.6% on antidepressant medications, and 0.07% to 0.09% incidence in the general population) | ||
| + | * High-frequency rTMS is contraindicated in patients with a history of seizures, but low-frequency rTMS has been demonstrated to be safe in patients with epilepsy. | ||
| + | |||
| + | ===== Adverse Events ===== | ||
| + | * The most common adverse effects for rTMS are scalp pain during stimulation (∼40%) and transient headache post-stimulation (∼30%). Both diminish over the course of treatment and usually respond to over-the-counter analgesia.[([[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4994792/|Milev, R. V., Giacobbe, P., Kennedy, S. H., Blumberger, D. M., Daskalakis, Z. J., Downar, J., ... & CANMAT Depression Work Group. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 4. Neurostimulation treatments. The Canadian Journal of Psychiatry, 61(9), 561-575.]])] | ||
| + | * rTMS does not appear to worsen cognition and also has little evidence of improving cognition. | ||
| + | |||
| + | ===== Pearls ===== | ||
| + | * Most rTMS studies use rTMS as an add on treatment to individuals already on antidepressant medications. | ||
| + | |||
| + | ===== Comparison with Other Brain Stimulation Therapies ===== | ||
| + | ==== Depression ==== | ||
| + | {{page>brain-stimulation:tdcs#depression&nouser&noheader&nodate&nofooter}} | ||