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Repetitive Transcranial Magnetic Stimulation (rTMS) and P50 Evoked Potential Component (rTMS-P50)

This study has been completed.
ClinicalTrials.gov Identifier:
First Posted: November 8, 2011
Last Update Posted: June 10, 2013
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by (Responsible Party):
University Hospital, Caen

The repetitive transcranial magnetic stimulation (rTMS) is a recent technique that has demonstrated its efficiency in both depression and schizophrenia. However if its efficiency has been recognized by the scientific community and the clinicians, its action on neurons and cerebral networks remains debated.

In the motor regions, the different rTMS studies generally use frequencies of stimulation of 1 to 40 Hz with differential effects; the low frequencies being associated with an inhibitory effect whereas highest frequencies have rather some facilitator effects as attested by the motor responses. What is valid for the motor system is not however necessarily applicable to other cerebral regions that have different neuronal organizations. If it is easy to observe these opposite effects of rTMS on the motor system (presence or absence of movements), these potential effects on more integrated cortex involved in high level functions have not been proved.

One of the possibilities to interpret the effects of the rTMS in no-motor cerebral regions would be to study the modifications of the EEG before and after rTMS and to see if a differential effect of the high and low frequencies of stimulation exists. Up to now, the studies having coupled these two techniques have observed modifications of the brain electric activity only during some seconds to minutes after rTMS, what appears in contrast with the clinical effects observed after a long delay (several days).

The contribution of our research resides in the use of the paradigm of suppression of P50 evoked potential component before and after rTMS tested with low and high frequencies of stimulation. This paradigm consists in two identical auditory stimuli presented at a very short interval (generally 500 milliseconds), the second sound generating a P50 wave of weaker amplitude than the first or being completely abolished in healthy subjects. However, this effect that has been well studied could result from an inhibitory action due to the gabaergic interneurons on the pyramidal neurons of the cortex. Thus, the investigators hypothesize that high frequency rTMS would have a facilitator effect on temporal lobe and so would induce no suppression of the P50 after-rTMS whereas low frequency rTMS would induce an inhibitory effect marked by a greater suppression of the P50.

Methods: 30 healthy subjects (of which 16 women) will be included after written consent. They will receive after randomization 2 sessions of rTMS in cross over at 1Hz and 20Hz at 30 days interval. An EEG and a P50 evoked potential will be done before and after rTMS. The site of stimulation will be determined by neuronavigation and will correspond to the maximal activation cluster generated by a language task during functional magnetic resonance imaging. The main judgment criterion is the S2/S1 ratio of the P50. The potential secondary effects will be evaluated (UKU adapted). The secondary criteria are the comparisons before and after rTMS of EEG spectrums in the alpha, beta and gamma bands.

Condition Intervention Phase
Depression Schizophrenia Procedure: high-frequency of repetitive transcranial magnetic stimulation (rTMS) Procedure: low frequency of repetitive transcranial magnetic stimulation (rTMS) Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Evaluation of Effect of Low and High-frequencies of Repetitive Transcranial Magnetic Stimulation (rTMS) by the Suppression of P50 Evoked Potential Component (rTMS-P50)

Resource links provided by NLM:

Further study details as provided by University Hospital, Caen:

Primary Outcome Measures:
  • P50 Ratio Stimulation 2/S stimulation 1 [ Time Frame: day of stimulation (day 1) ]

Enrollment: 30
Study Start Date: May 2011
Study Completion Date: June 2013
Primary Completion Date: June 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
high frequency rTMS Procedure: high-frequency of repetitive transcranial magnetic stimulation (rTMS)
frequency of stimulation of 20 Hz
low frequency rTMS Procedure: low frequency of repetitive transcranial magnetic stimulation (rTMS)
frequency of stimulation of 1 Hz


Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • healthy subjects, right-handed, aged from 18 to 60 years
  • written consent
  • with social security

Exclusion Criteria:

  • pregnancy, breastfeeding
  • brain tumor or epilepsy
  • psychiatric, neurological or ear-nose-throat disorders, current or past
  • healthy subjects with psychotropic drugs or with substance abuses
  • healthy subjects with tabacco weaning
  • protected major with tutor
  • counter-indication to MRI and rTMS
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01466439

Caen University Hospital, department of psychiatry and explorations fonctionnelles neurologiques
Caen, France
Sponsors and Collaborators
University Hospital, Caen
Principal Investigator: Pr Sonia Dollfus, MD, PhD University Hospital, Caen
  More Information

Responsible Party: University Hospital, Caen
ClinicalTrials.gov Identifier: NCT01466439     History of Changes
Other Study ID Numbers: 09-181
First Submitted: October 19, 2011
First Posted: November 8, 2011
Last Update Posted: June 10, 2013
Last Verified: June 2013

Keywords provided by University Hospital, Caen:
physiological process
brain changes

Additional relevant MeSH terms:
Schizophrenia Spectrum and Other Psychotic Disorders
Mental Disorders