RedCardinal - 6:15 am on Oct 16, 2012 (gmt 0)
I'm looking at an EMD that initially lost #1 down to #3-6 after EMD launch. As of mid-late last week it regained #1 again.
The odd issue is that this domain was hit by Penguin 1, and seemed to come out of that to some extent with latest Penguin refresh. Many rankings that had plunged from top 10 to >100 with Penguin are now coming back in #30-40s.
Onto whether this domain lost other rankings at same time as EMD launch - the answer is yes. Many synonyms that ranked top 1-3 dropped to #4-10 or lower. Site carries no ads, professional design, and robust unique content. Site measures user satisfaction with qualitative exit surveys. I think unlikely to be Panda.
Here's the fly - there's no way to hold everything else constant to identify which variable caused these drops. Perhaps folks with EMDs that were unaffected by Panda/Penguin previously can chime in with data on whether any other keyword phrases were affected by EMD update.
My case is probably too convoluted to be worthwhile, and as with everything else in search YMMV.