1 Division of Neonatology, Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan; Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan.
2 Department of Neurology, Nagano Children's Hospital, Azumino, Japan.
3 Department of Pediatrics, Suwa Red Cross Hospital, Suwa, Japan.
4 Department of Pediatrics, Ina Central Hospital, Ina, Japan.
5 Department of Pediatrics, Iida Municipal Hospital, Iida, Japan.
6 Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan. Electronic address: inabay@shinshu-u.ac.jp.