In contrast, Manser says, a person's passive vocabulary consists of the words whose meanings they knowâso that they do not have to look the words up in a dictionaryâbut which they would not necessarily use in ordinary conversation or writing (The Penguin Writer's Manual, 2004).
Sleep Apnea, Night Terrors, and Nightmares. Sleep apnea may also be to blame for your nightmares. During sleep apnea, your brain senses the low oxygen and realizes that you are under a very real threatâyou are being choked or smothered by your own bodyâand if nothing is done you will die.
Sleep Apnea. 1  As many as 20% of PD patients may have sleep apnea. 2  Sleep apnea refers to a significant difficulty with breathing during sleep. 3  Sleep apnea is a major cause of nighttime insomnia and daytime sleepiness. It also reduces oxygen flow to the brain which in turn impairs concentration and thinking during the daytime.