Sleep disorders are conditions that prevent you from sleeping well on a regular basis. They are very common, affecting an estimated 75 percent of Americans on a regular basis. There are more than 100 different types of sleep disorders; the most common are: snoring, obstructive sleep apnea (OSA), central sleep apnea (CSA), insomnia, narcolepsy, parasomnia (abnormal movements and behavior during sleep), hypersomnia (excessive sleepiness), restless leg syndrome, circadian rhythm disorders.