Sleep doc recommending lumbar puncture

My new sleep doc wants me to get a lumbar puncture. She says she'd be shocked if I didn't have N1.

I recently had an MSLT done at a different sleep center. According to the PA who interpreted it, it was inconclusive. My sleep latency was 8.4 minutes and I didn't ever hit REM. But my new doc (an MD and sleep expert) thinks the last place messed up my test. Apparently I didn't do a long enough medication washout. Also I also had a panic attack during two of the naps which skewed my sleep time.

I have frequent, intense cataplexy. My legs, hands and jaw go limp and weak when I get angry or happy, or after sex, or when I laugh. I had experienced excessive daytime sleepiness and hallucinations around sleep since puberty. I have two uncles with type 1 narcolepsy.

Anyway the doc wants to do a lumbar puncture so insurance will approve my meds. I am planning to do this, but I am nervous! Anyone in a similar boat get the test? What was your experience like?