1. Department of Audiology and Speech-Language Pathology, University of North Texas, 1155 Union Circle #305010, Denton, Texas 76203-5017, USA
2. Speech and Hearing Sciences, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, Alabama 35294, USA
3. Advanced Telecommunications Research Institute International, 2-2-2 Hikaridai Seika-cho, Sorakugun, Kyoto, 619-0288, Japan
4. Department of Informatics, The Open University of Japan, 2 Chome-11 Wakaba, Mihama Ward, Chiba, 261-8586, Japan