Mechanisms of Seizure Spread and Generalization Studied by SPECT Difference Imaging of ECT-Induced Seizures
Hal Blumenfeld, M.D., Ph.D.
Yale University School of Medicine, New Haven, CT
David Mahoney Neuroimaging Program
December 1999, for 2 years
Hal Blumenfeld, M.D., Ph.D.
Assistant Professor of Neurology and Neurobiology, Yale University School of Medicine
We propose that bilateral and unilateral electroconvulsive therapy (ECT)-induced seizures can, respectively, be used as model systems for generalized and partial onset epileptic seizures. Bilateral ECT will produce symmetric blood flow changes in bilateral cortical and subcortical structures, while unilateral ECT will cause asymmetric cortical changes, and less profound changes in subcortical structures.
To investigate in detail the timecourse of cortical and subcortical cerebral blood flow (CBF) changes during seizures in humans. Understanding the anatomical brain regions involved and the timecourse of their involvement during bilateral and unilateral ECT-induced seizures may help elucidate the fundamental mechanisms for the therapeutic and adverse effects of ECT. These results may also have applications to understanding spontaneous epileptic seizures in humans.
Seizures are induced with unilateral and bilateral electroconvulsive therapy stimulation protocols. CBF is measured using single-photon emission computerized tomography (SPECT) ictal-interictal difference imaging, and compared to SPECT measurements performed during spontaneous seizures in patients with epilepsy. SPECT scans are coregistered with MRI scans for anatomic localization, and are analyzed using statistical parametric mapping (SPM 99).
Enev M., McNally K.A., Varghese G., Zubal I.G., Ostroff R., and Blumenfeld H. Imaging onset and propagation of ECT-induced seizures .Epilepsia. 2007 Feb;48(2):238-44.
McNally K.A., Paige A.L., Varghese G., Zhang H., Novotny E.J., Spencer S.S., Zubal I.G., and Blumenfeld H. Localizing Value of Ictal-Interictal SPECT Analyzed by SPM (ISAS). Epilepsia. 2005 Sep;46(9):1450-64.
Blumenfeld H., Rivera M., McNally K.A., Davis K., Spencer D.D., and Spencer S.S. Ictal neocortical slowing in temporal lobe epilepsy. Neurology. 2004 Sep 28;63(6):1015-21.
Blumenfeld H., McNally K.A., Vanderhill S.D., Paige A.L., Chung R., Davis K., Norden A.D., Stokking R., Studholme C., Novotny E.J., Zubal I.G., and Spencer S.S. Positive and negative network correlations in temporal lobe epilepsy. Cereb Cortex. 2004 Aug;14(8):892-902.
McNally K.A. and Blumenfeld H. Focal network involvement in generalized seizures: new insights from electroconvulsive therapy. Epilepsy Behav. 2004 Feb;5(1):3-12.
Blumenfeld H. and Taylor J. Why do seizures cause loss of consciousness? Neuroscientist. 2003 Oct;9(5):301-10.
Blumenfeld H., McNally K.A., Ostroff R., and Zubal I.G. Targeted prefrontal cortical activation with bifrontal ECT. Psychiatry Res. 2003 Jul 30;123(3):165-70.
Blumenfeld H., Westerveld M., Ostroff R.B., Vanderhill S.D., Freeman J., Necochea A., Uranga P., Tanhehco T., Smith A., Seibyl J.P., Stokking R., Studholme C., Spencer S.S., and Zubal I.G. Selective frontal, parietal and temporal networks in generalized seizures. Neuroimage. 2003 Aug;19(4):1556-66.
Chang D., Zubal I.G., Gottschalk C., Necochea A., Stokking R., Studholme C., Corsi M., Slawski J., Spencer S.S., and Blumenfeld H. Comparison of statistical parametric mapping and SPECT difference imaging in patients with temporal lobe epilepsy. Epilepsia. 2002 Jan;43(1):68-74.