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From: Janis Ingham
Date: 10/13/02
Time: 5:11:15 PM
Remote Name: 68.6.68.82
Dear Mr. Stenzel - Thanks for your good wishes for our research and for raising the issue of TMS (transcranial magnetic stimulation). We have been and are conducting research using this methodology. At the end of this reply I've provided a reference to one of our reports that might interest you. To date, we have not found TMS to be useful in producing reductions in stuttering. Even the reports of its positive effect on depression are receiving criticism these days.
The use of TMS presents certain problems in regard to the study of stuttering. First, the typical effects of TMS are to increase activation in the area of the brain that is stimulated. For the most part, our research has pointed to areas of the brain that are "overactive" among stutterers; therefore, increased activation would not be expected to help the problem. In regard to the temporal lobe, which we have found to be consistently inhibited during stuttering, the application of TMS is too painful for subjects to be able to tolerate sustained stimulation. Another problem with TMS in its current development is that it only reaches areas of the brain that are relatively superficial; so if a crucial brain area related to stuttering (e.g., insula) is very medial, TMS can't reach it. One more difficulty with current TMS methodology is that it is difficult to "aim" it very precisely and to know exactly what part of the brain is being stimulated during the pulses - unless the process is being monitored by PET or fMRI (and getting the TMS paddles properly in place while someone is in the PET or the MRI is not easy (especially given the magnetic attraction carried by the MRI). Our colleagues at the Resarch Imaging Center at the University of Texas, San Antonio are developing a computer-guided robot that will facilitate precise aiming of the TMS stimulus, guided by the subject's on MRI. That'll be a big step forward. So, we're going to continue to pursue TMS with people who stutter. We agree with you that if appears to have potential.