Transcranial Magnetic Stimulation(TMS)

By: Brandon Brunelle

What is it

• Trancranial Magnetic Stimulation is a method used to treat migrains, migrain “aura”, and even depression

• 10-20% of people suffer from migrains alone• Relatively new concept• Not yet widely used or accepted by insurance

Background

• The skull acts as a shield

• Different parts of the brain have different functionality

• Brain is made up of neurons and neuron clusters that are electrically excitable

The Concept• Migrains are associated

with high neuron activity• Depression associated

with low neuron activity.• Use a magnetic coil to

modulate neuron activity• Coil is placed on scalp in a

desired location• Magnetic field penetrates

to a depth of about 3cm• Approximately three times

the normal neuron excitation stimulation is needed to modulate

Components

• 24V voltage source/high voltage module

• Bipolar condensors

• Snubber circuit• Control circuits• Copper coil

High voltage module

• Delivers an adjustable positive voltage that is highly stable

• Custom 10 watt and high voltage module• Charges condensers in about 23 seconds• High voltage double pole inverter

Condensors

• Metal impregnated polypropylene dielectric with 1500volt insulation.

• Used to deliver high current discharges in about 100uS.

Control Circuit

•Allows for selection of polarity•Amplitude adjustment

Snubber Circuit

• Uses two Thyristor to deliver current to coil in order to provide positive and negative current

• 1800V insulation• Transfers peak current of 8000A for 10ms• Time derivatives were 250A/uS, 1000V/uS• Circuit contains about a 4.3uS lag time causing

polarity to undesirably change in coil• Snubber circuit contained an R-C setup in paralell

with thrystors to prevent polarity change

Copper Coil

• Coil has a diameter of 11 cm

• Made of flat enameled copper wire

• Insulated to prevent coil unwinding

Benefits

• Non invasive• Relatively quick and easy• Does not cause any sort disfunctionality• Would not cost a lot• No chemical imbalances that drugs and

medication can cause• 74% success rate after two hours in test

Sources• Design and Construction of a Portable Transcranial Magnetic Stimulation (TMS)

Apparatus for Migraine Treatment: Anne Beuter, Isabelle Lagroye, Bernard Veyret University of Bordeaux 1,IMS, Site ENSCPB,UMR CNRS 5218,16, Avenue Pey Berland, 33607, Pessac Cedex, France

• http://intra.ninds.nih.gov/images/Research_Images/wassermanne@ninds.nih.gov.jpg

• http://www.mclean.harvard.edu/patient/adult/tms.php• http://en.wikipedia.org/wiki/Transcranial_magnetic_stimulation• http://www.nami.org/Content/ContentGroups/Helpline1/

Transcranial_Magnetic_Stimulation_%28rTMS%29.htm