1. Department of Informatics, Faculty of Information Science and Electrical Engineering, Kyushu University 1 , Fukuoka 819-0395, Japan
2. Department of Informatics, Graduate School of Information Science and Electrical Engineering, Kyushu University 2 , Fukuoka 819-0395, Japan
3. Medical Equipment Division, RION CO., LTD 3 , Tokyo 185-8533, Japan
4. Department of Otorhinolaryngology, Tokyo Saiseikai Central Hospital 4 , Tokyo 108-0073, Japan
5. Keio University School of Medicine 5 , Tokyo 160-8582, Japan
6. Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center 6 , Tokyo 152-8902, Japan mori@inf.kyushu-u.ac.jp , oba91321@gmail.com , t-morimoto@rion.co.jp , okamotoy.10@kdt.biglobe.ne.jp , shokanza@yahoo.co.jp