1. Department of Neurosurgery, Kumamoto General Hospital, Yatsushiro, Japan.
2. Department of Neurosurgery, Amakusa Medical Center, Amakusa, Japan.
3. Division of Speech-Language and Hearing Therapy, Faculty of Health Science, Kumamoto Health Science University, Kita-Ku, Japan.
4. Department of Neurosurgery, Kumamoto Neurosurgical Hospital, Chuo-Ku, Kumamoto, Japan.