TMS is simply the application of the principle of induction to get electrical current across the insulating tissues of the scalp and skull without discomfort. A coil of wire, encased in plastic, is held to the head. When the coil is energized by the rapid discharge of a large capacitor, a rapidly changing current flows in its windings. This produces a magnetic field oriented orthogonally to the plane of the coil. The magnetic field passes unimpeded through the skin and bone of the head, inducing an oppositely directed current in the brain that flows tangentially with respect to skull. The current induced in the structure of the brain activates nearby nerve cells in much the same way as currents applied to directly to the cortical surface.

Of course, rTMS could only be used to treat diseases whose functional causes are understood. Recent progress in understanding the mechanisms behind depression, obsessive-compulsive disorder, and neurological diseases like Parkinson's and Huntington's, offers some hope in these areas. rTMS is currently under study as a treatment for severe depression, mania, auditory hallucinations, posttraumatic stress disorder, migraine headaches and tinnitus. It is particularly interesting as it may provide a viable treatment to certain aspects of drug resistant mental illness, particularly as an alternative to electroconvulsive therapy. rTMS is also under investigation for the treatment of drug-resistant epilepsy and tinnitus.
Although research in this area is in its infancy, there is now some evidence that rTMS is an effective treatment for both depression and auditory hallucinations, with more symptoms and disorders being researched.

rTMS

• First TMS capable of delivering a pulse every three seconds (as diagnostic aids for neurologists.)
• New machines which can give up to 50 stimuli per second (rTMS)
• A non-invasive technique, free of serious side effects, easily modifying activity of specific brain areas

• rTMS gives short pulses of magnetic energy to Limbic system structures
• Small electric charges can cause the neurons to fire or to become active

Ilmoniemi et.al.(1997) were able to measure with QEEG just seconds after electromagnetic pulse

• Nashaat et.al (2001),
• Nikulin et.al (2003),
• Kommsi et.al (2004) have used ongoing rTMS and QEEG Monitoring
  

Brain electrical activity changes with rTMS

• Acute rTMS induces changes in regional activity throughout the brain
• Stimulation intensity is important
• Low frequency has a tendency to decrease
• High frequency has a tendency to increase

Resynchronization effects

• Normal brain function requires synchronized activity of interconnected brain areas
• rTMS may help 'reset' the normal synchrony between brain regions
  (Garcia-Toro et.al. 2001, Avery 2004)

GABA and QEEG

• GABA increases functional connectivity on QEEG (Benzodiazepine effect)
• GABA decreases with stress
• GABA decreases in plasma and in brain (MRS) of depressed patients
• ECT increases GABA level in depressed patients.
• rTMS: increase ?
State marker improves after treatment
• Trait marker doesn't improve after treatment

'State markers' of QEEG being:

• Ratio of Alpha waves
• Ratio of Delta waves
• Hemispheric asymmetry
• Alpha/Delta ratio of the frontal area

Acute drug effect in QEEG

• Tricyclic Antidepressant drugs: Alpha, Theta, Delta
• Antipsychotic drugs :Theta and Delta waves
• Antianxiety drugs :beta
• Cognitive activator drugs : Alpha
• SSRI drugs: Alpha (Itil 1989)

The Response to drug treatment in depression

• Delta waves: good response,
• Alpha and Beta waves: good response,
• Unchanged QEEG: bad response. (Kendler)

The Distribution of Brain waves in QEEG after 10 sessions of rTMS (preliminary findings)

According to HAM Scores
HAM Scores and QEEG after 10 sessions of rTMS "An interpretation"

• All patients showed 30-50% treatment response
• In Alpha increases group, HAM improvement was greater
• In no changes group, HAM improvement was minimal
• More verification, and MEG studies, are necessary

Pregnancy and rTMS (Case Study I)

• One case (I.D., 32 years)
• She had serious non-psychotic Chronic Major Depression.
• She used antiepileptic and antidepressant drugs.
• She became pregnant during treatment.
• She wanted to continue the pregnancy.

Pregnancy and rTMS (Case Study II)

• Firstly, we stopped her using the antidepressant drugs
• We applied 40 sessions of rTMS to her.
• Every session was 25 Hz. and 1000 pulses.
• Now, she has a healthy baby.
• After birth, rTMS was continued.

Frequency of seizures

• We applied rTMS at approximately 15,000 sessions in two years
• In every session, rTMS was applied at 25 Hz
• In most cases, 1000 pulses were applied in every session
• Grandmal seizures were observed only in 3 cases.(3 /15,000)

• 25 Hz, 1 Pulses, 50% Power
• 25 Hz, 1 Pulses, 100% Power
• 25 Hz, 3 Pulses, 100% Power
• 5 Hz, 10 Pulses, 50% Power, Duration 1.8 sec
• 5 Hz, 10 Pulses, 75% Power, Duration 1.8 sec
• 5 Hz, 10 Pulses, 100% Power, Duration 1.8 sec
• 25 Hz, 50 Pulses, 50% Power, Duration 1.9 sec
• 25 Hz, 50 Pulses, 75% Power, Duration 1.9 sec
• 25 Hz, 50 Pulses, 100% Power, Duration 1.9 sec

Scientific Inspiration

• One day, in 1990 at a London Hospital in an elevator, a passenger was giggling. A magnetic stimulation had been applied to his head. It was a neuro-diagnostic motor test, for thumb jerk
• Dr. Mark George observed and was astonished by this situation. He suspected that magnetic fields could move much more than the thumb.
• The story of magnetic therapy in psychiatry started like this.