The first helps you control your vertical velocity to limit the risks of ear barotrauma and DCI.

上升/下降绳可以帮助你控制垂直方向的速度并以此来降低耳朵的气压性创伤和减压病症的危险。

When barotrauma has occurred in the middle ear, it is not unusual for the diver to have a sensation of pressure or fullness and decreased hearing.

当中耳受到气压性创伤的时候，潜水者会经常有压力、充塞和听力下降的感觉。