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 Research & Giving News Article  NARSAD researchers have been prominent in this field of study, including pioneering TMS researchers Robert Belmaker, M.D., of Ben Gurion University (1994 Distinguished Investigator/2000 NARSAD Falcone Prize recipient), and Mark George, M.D., of the Medical University of South Carolina (1996 Young Investigator/1998 Independent Investigator). Two current NARSAD researchers taking this line of investigation in exciting new directions are Sarah Lisanby, M.D., of Columbia University (2003 Independent Investigator/former 1996 Young Investigator), and Ralph Hoffman, M.D., of Yale University (2003 Independent Investigator/former 1998 Independent Investigator). Dr. Lisanby is studying Magnetic Seizure Therapy (MST) which uses TMS to induce a seizure as an alternative to Electroconvulsive Therapy for severe depression, and Dr. Hoffman is utilizing TMS for treating auditory hallucinations in schizophrenia patients. Magnetic Seizure Therapy Utilizing TMS Despite advances in pharmacology, treating depression continues to challenge clinicians, as symptoms can remain resistant to conventional drug therapies. Pioneered in the 1930’s, Electroconvulsive Therapy (ECT) has been used successfully for treating medication-resistant depression. ECT administers a small electrical current to the brain through electrodes on the scalp, inducing a seizure that can disrupt major depression. While effective, ECT’s adverse cognitive effects, such as memory loss, make it an imperfect solution, and scientists have been seeking a method that duplicates ECT’s benefits while avoiding its drawbacks. Magnetic Seizure Therapy (MST) may be such a method, and Dr. Lisanby has embarked upon a study to explore the relative efficacy of two ways of administering MST for treating both unipolar and bipolar depression. In ECT, the skull interferes with the electrical current, shunting most of the stimulus through the scalp and cerebrospinal fluid. Individual differences in skull anatomy add to the difficulty of controlling the amount and direction of current administered. MST, however, utilizes the magnetic fields of TMS to create the seizure. These fields pass freely through the scalp and skull, providing much better control over dosage and targeting within the brain. Dr. Lisanby’s previous work has shown MST to be effective for treating depression with significantly fewer side effects than ECT, even though the commonly used MST device cannot deliver an optimal dosage to the prefrontal cortex. She will now test a new MST device (one that focuses seizures in the prefrontal cortex) and compare its efficacy with the present device (one that provides non-focal stimulation of large areas). MST utilizes TMS as an alternative means of producing a seizure in the brain; however, also of interest to researchers is whether the targeted nature of TMS could eliminate the need to stimulate the brain to the point of convulsion in order to alleviate depression. Dr. Lisanby commented on subconvulsive TMS, saying, “It may be that some patients with more severe depression will continue to need a more robust and definitive treatment. Therefore, I do not see it as an either/or situation, but rather that we should develop all potentially helpful avenues for using brain stimulation to treat depression.” Schizophrenia and TMS Exploring an innovative treatment approach, Dr. Hoffman has found repetitive transcranial magnetic stimulation (rTMS) to be beneficial for treating the auditory hallucinations associated with schizophrenia. Approximately 50 to 70% of schizophrenia sufferers “hear voices”, a symptom which often proves resistant to medication therapy. In his continuing investigations in this area, Dr. Hoffman will utilize functional magnetic resonance imaging (fMRI) to map out the various brain regions responsible for these hallucinations. In a clinical trial of patients with very frequent auditory hallucinations, he will then use these maps to position rTMS at multiple, targeted sites, in order to determine if targeted treatment is more effective than rTMS delivered to a single “standard” site. This research will enable us to better understand the neurological basis of auditory hallucinations and may lead to non-pharmacological treatments for this difficult aspect of schizophrenia. |
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