Additionally, the arousalthreshold falls as we age, so that sounds and other interruptions are more likely to awaken us.
另外，随着年龄的增加，半夜惊醒的次数也逐渐增多，声音或其它干扰都很有可能吵醒我们。
2
The average of intensities of the maximum stimulus not causing arousal and the minimum stimulus causing arousal is considered as current perception threshold.