i listened to electro/house/dance music ~130-140 BPM and it helped me concentrate when doing light study such as further maths, but distracted me for harder subjects that need heavier thinking.
also when i did practice exams i didnt listen to music as i thought it would make sense to replicate the exam environment as much as possible (otherwise i would if they played party music during exams) 
^^ Pretty much the same here. I actually find it weird to study without music, have no clue why, but it just seems 'right'. But yeah, whenever I studied, regardless of how intense the studying I had to do was, I listened to trance music all the time (~130-140 BPM). I guess the fact that the drum patterns are pretty repetitive, there's (on the whole) a lack of lyrics (but even with lyrics, they seem to put you in the 'zone') and there's a focus on melody in each track just has some kind of remedial effect I guess, not so much a distracting effect. But yeah, if you're gonna listen to any trance (if that's kinda your thing), listen to progressive, melodic or vocal trance (not 'hardstyle', if you can even call that music

, would be way too much of a distraction, it's more in your face).