transcranial magnetic stimulation julia shannon bme 281 october 11, 2011
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Transcranial Magnetic StimulationTranscranial Magnetic Stimulation
Julia ShannonBME 281October 11, 2011
What is it?What is it?
A procedure that uses magnetic fields to A procedure that uses magnetic fields to stimulate nerve cells in the brain stimulate nerve cells in the brain
Relatively new Relatively new Since development, has been used in Since development, has been used in
many fields of researchmany fields of research Use of magnets, instead of a direct electric Use of magnets, instead of a direct electric
current to the brain, allows for mapping of current to the brain, allows for mapping of the cerebral cortex and its connectionsthe cerebral cortex and its connections
First useFirst use
1985-Anthony Barker conducted the 1985-Anthony Barker conducted the first successful TMS study in first successful TMS study in Sheffield, EnglandSheffield, England
Stimulated muscle contractionStimulated muscle contraction -conducted nerve impulses from the motor cortex -conducted nerve impulses from the motor cortex
to the spinal cordto the spinal cord
How does it work?How does it work?
A large electromagnetic coil is placed A large electromagnetic coil is placed against the scalpagainst the scalp
Uses a magnetic field to create weak Uses a magnetic field to create weak electric currents that stimulate nerve electric currents that stimulate nerve cells in a region of the brain cells in a region of the brain
Causes depolarization or hyper Causes depolarization or hyper polarization in neuronspolarization in neurons
Clinical usesClinical uses
Tested as a treatment for various neurological Tested as a treatment for various neurological and psychiatric disordersand psychiatric disorders
Used today to improve symptoms of depressionUsed today to improve symptoms of depression Stimulating the nerve cells creates mood changeStimulating the nerve cells creates mood change Used when standard procedures have no effect Used when standard procedures have no effect Least invasiveLeast invasive (doesn’t require surgery or implantation of electrodes) (doesn’t require surgery or implantation of electrodes) 164 patients with unipolar, non-psychotic major 164 patients with unipolar, non-psychotic major
depressive disorder were treated with TMS. depressive disorder were treated with TMS. Within 30 days..Within 30 days..
-1/3 reported complete resolution-1/3 reported complete resolution -1/2 reported significant improvement-1/2 reported significant improvement
ProcedureProcedure
Doctor places coil against Doctor places coil against
head- mapping signalshead- mapping signals
Increase of magnetic Increase of magnetic
dosage until fingers or dosage until fingers or
hands twitchhands twitch
(motor threshold)(motor threshold)
Treatments are Treatments are typically given daily, typically given daily, for 30-40 minutes, in a for 30-40 minutes, in a span of 4-6 weeks.span of 4-6 weeks.
Stimulation is gradualStimulation is gradual Repetitive TMS Repetitive TMS
produces longer-produces longer-lasting effects which lasting effects which persist past the initial persist past the initial period of stimulation period of stimulation
Coil TypesCoil Types
Can differ in geometry of the coil, the type Can differ in geometry of the coil, the type of material usedof material used
Designs of different coils used can have a Designs of different coils used can have a big impact on the resulted stimulationbig impact on the resulted stimulation
Ex: figure-eight coil results in more focal pattern of Ex: figure-eight coil results in more focal pattern of activation,activation,
double-cone coil used for deeper stimulationdouble-cone coil used for deeper stimulation
Risks and Side EffectsRisks and Side Effects
Common:Common:Headache, scalp discomfort, tingling or Headache, scalp discomfort, tingling or
twitching of facial muscles, twitching of facial muscles, lightheadednesslightheadedness
Less Common:Less Common:
Seizures, maniaSeizures, mania
The NeuroStar, a device used for TMS, was The NeuroStar, a device used for TMS, was cleared by the FDA in 2008cleared by the FDA in 2008
Improvements in symptoms may last for Improvements in symptoms may last for days/weeks/monthsdays/weeks/months
Other areas of research include Other areas of research include -rehabilitation of motor disability after stroke -rehabilitation of motor disability after stroke -evaluating damage from strokes, spinal cord -evaluating damage from strokes, spinal cord
injuries, Multiple Sclerosis, and motor injuries, Multiple Sclerosis, and motor neuron neuron diseasedisease
- itraoperative monitoring- itraoperative monitoring
TMS machine designed in 1992: stimulate or slow TMS machine designed in 1992: stimulate or slow down regions of the brain so that doctors could down regions of the brain so that doctors could monitor the effects of the surgery in real timemonitor the effects of the surgery in real time
Allan Snyder- theorized that people could tap into Allan Snyder- theorized that people could tap into genius-like mental ability when undergoing TMSgenius-like mental ability when undergoing TMS
(Having a mental impairment would allow other mental (Having a mental impairment would allow other mental functions to flourish)functions to flourish)
40% of test subjects displayed extraordinary and 40% of test subjects displayed extraordinary and newfound mental skills.newfound mental skills.
SourcesSources Yang, Sarah. "09.27.2007 - Neuroscientists Connect Neural Activity and Blood Flow in Yang, Sarah. "09.27.2007 - Neuroscientists Connect Neural Activity and Blood Flow in
New Brain Stimulation Technique." New Brain Stimulation Technique." University of California, BerkeleyUniversity of California, Berkeley. Web. 08 Oct. . Web. 08 Oct. 2011. <http://berkeley.edu/news/media/releases/2007/09/27_TMS.shtml>. 2011. <http://berkeley.edu/news/media/releases/2007/09/27_TMS.shtml>.
Fallon, Sean. "NeuroStar TMS Depression Therapy System First To Be Given FDA Fallon, Sean. "NeuroStar TMS Depression Therapy System First To Be Given FDA Approval." Approval." Gizmodo, the Gadget GuideGizmodo, the Gadget Guide. Web. 08 Oct. 2011. . Web. 08 Oct. 2011. <http://gizmodo.com/5403423/neurostar-tms-depression-therapy-system-first-to-be-<http://gizmodo.com/5403423/neurostar-tms-depression-therapy-system-first-to-be-
given-fda-approval>.given-fda-approval>. "Savant for a Day." "Savant for a Day." BioteleBiotele. Web. 08 Oct. 2011. . Web. 08 Oct. 2011.
<http://www.biotele.com/savant.htm>. <http://www.biotele.com/savant.htm>. Staff, Mayo Clinic. "Transcranial Magnetic Stimulation - MayoClinic.com." Staff, Mayo Clinic. "Transcranial Magnetic Stimulation - MayoClinic.com." Mayo ClinicMayo Clinic. .
Web. 08 Oct. 2011. <http://www.mayoclinic.com/health/transcranial-magnetic-Web. 08 Oct. 2011. <http://www.mayoclinic.com/health/transcranial-magnetic-stimulation/MY00185>. stimulation/MY00185>.
"Transcranial Magnetic Stimulation." "Transcranial Magnetic Stimulation." NeurologyNeurology. Web. 08 Oct. 2011. . Web. 08 Oct. 2011. <http://www.neurology.org/content/68/7/484.short>. <http://www.neurology.org/content/68/7/484.short>.
"Transcranial Magnetic Stimulation." "Transcranial Magnetic Stimulation." Wikipedia, the Free EncyclopediaWikipedia, the Free Encyclopedia. . Web. 08 Oct. 2011. Web. 08 Oct. 2011. <http://en.wikipedia.org/wiki/Transcranial_magnetic_stimulation>.<http://en.wikipedia.org/wiki/Transcranial_magnetic_stimulation>.