1. Department of Speech and Hearing Sciences, University of Arizona, Tucson, Arizona 85721-0071
2. National Center for Voice and Speech, Wilbur James Gould Voice Research Center, Denver Center for the Performing Arts, Denver, Colorado 80204 Department of Speech Pathology and Audiology, University of Iowa, Iowa City, Iowa 52242
3. Division of Physiologic Imaging, Department of Radiology, University of Iowa College of Medicine, Iowa City, Iowa 52242