I have undergone a sleep study, that's my only qualification to comment, that and a long life's experience... and old guy.
I read you do not suffer from Obstructive Sleep Apnea.. look right and while I don't recall the % time in REM needed to be rested in the morning, you must have been given the number. In my case I was told I was marginally well rested relative to test results, but do suffer from mild sleep apnea. I don't know how much time you spent below 90% but any time isn't good.
Ambien or similar have problems, discuss Tranzodone with your doctor as asleep and emotional aid. I am trying that myself, at 50 mg, may ask to go to 100 mg as the current dose used for the past 6 days helps, but I think a stronger dose would be better as I am not having any troublesome side effects.
First of all, I'm sorry the doctor who ordered your testing didn't go more in depth in explaining the results to you. The information I'm going to give you here is based strictly upon the diagnostic criteria for different conditions; doctors use a combination of test results and diagnostic guidelines AND clinical expertise to reach diagnosis and treatment decisions, so there is no guarantee that this information pertains to your case in particular.
The two main things looked for to diagnose narcolepsy on polysomnography are very short onset of sleep (typically under 10 minutes) and excessively early onset of REM sleep. The sleep architecture may also vary in the total amount of REM sleep (excessive in narcolepsy). Looking at your numbers, it doesn't appear that you would meet the diagnostic criteria for narcolepsy; also, the fact that you can't nap during the day would go against a narcolepsy dx because there's a separate sleep study called an MSLT ("nap test") that you need to (pass/fail ... not sure how to put that) before getting diagnosed with narcolepsy. Did you have to stay after your overnight study and do another one that lasted into the afternoon where they ask you to nap over and over again?
I personally think it might be worthwhile to inquire about whether you meet the diagnostic criteria for Idiopathic Hypersomnia. Nuvigil is a medicine used to treat IH as well as narcolepsy, so it would fit with what the doctor has prescribed already.
I have narcolepsy myself and am familiar with up-to-date medical technology in this field, and I'm a bit surprised your doctor suggested narcolepsy based on those results. Do you have any of the other symptoms of narcolepsy besides excessive daytime sleepiness that might point more in that direction?
The other question I would have for your doctor would be what do those 100+ "other spontaneous arousals" mean? Were you given reference ranges for your results at all?
(I'm not routinely on this forum, so please send me a PM by hovering over my username and clicking "send message" in the dropdown menu, if you don't receive a response within 2-3 days of your reply. Thanks!)