登山の健耳聴力に及ぼす影響に就いて

　序言

　定型的C⁵dipは確かに音響性外傷の顕著な現象であるが，聴力曲線のC⁵dipは恒に必らずしも音響性外傷を意味しない。

　例えば各種中毒時の内耳障害の場合にも，頭部の鈍力外傷に際してもC⁵dipを見るが，河田，西藤氏（1953）は激しいスポーツの直後に健康な成年者に一時的に起るとし，柔道，拳闘，連続不眠の肉体労働作業でも本現象を見ている。

　余等は今夏登山の聴力に及ぼす影響に就いて調査したので茲に報告し，諸員の御批判を乞わんとするものである。

Hearing tests are performed among a num-ber of mountain climbers after attaining the peakot Shirouma Dake, altitude 2, 933 meters. Severe symptoms of mountain sickness were more prevalent among the females than the males and more among the group who were above the age of 30 than those who belong to the age-group 20-24. A C⁵ dip in the hearing test was noted after 5-6 hrs following the at-tainment of the altitude and among those who made the ascent for the first or second time. Three hours was the average duration of time required for the recovery of the disturbed hearing.