I didn't know there was a study, but I'll have to agree with the findings. When I was an H cup I had very little sensitivity in my nipples. I think it upset some lovers who had so much real estate to play with, but it was them having all the fun and I was wondering what all the fuss was about.
Then I had breast reduction surgery, and one of my questions during a post-op follow up was how did the surgeon rewire my nerves because it was night and day! All of a sudden I could feel everything! And it was almost too sensitive and reminded me of puberty, except not that painful.
It's settled down a bit, which is interesting because I was downsized to a D cup and have since settled into DD.
If you have a link to that study I'd love to read it.