You have no way of knowing if your stage 4 sleep is disturbed unless you did multiple 24hr EEG, sleep studies. The research says benzos do this, and up until a few years ago ALL sleeping meds were benzos (IE. restoril etc..) The newer meds interact with the benzodiazepine receptors in a very similar fashion, but have not been shown to decrease stage 4 sleep. Lunesta is the best and then Ambien.

Dr.S.