I played this Etude in College and it became my favorite piece ever. Even though the melody is right hand it is all about left hand technique. It has to be flexible, agile, and quick. Now about the memory. This one can be analyzed all you want, but in the end it is simply about playing the left hand almost on automatic pilot. It just moves as you simply sit back and watch the whole thing. Strange, isn't it? The thing that keeps the memory helpful is really that right hand. That is the easiest to see going. The left hand almost seems that it has to go on its own. Practice hands separate very slowly. Make sure that you memorize the left hand by itself and in very slow motion. That can give you some kind of security. But when it goes fast, you simply have to trust your mechanics that it will play. So play slowly together as you read the score. Do this many, many, many times. Then begin to memorize a few measures at a time. After you have it memorized, play slowly and with both hands. Then start to play each hand separately by memory, of course. Do this hand separate slowly, then at tempo.
That will do it. But this is going to take a lot of work and time. Of course to learn this piece, you do have to be advanced level. This piece can be figured harmonically, but still, when you are moving that left hand all over the place so swiftly, you can't capture all that analysis mentally. The analytical knowledge may stay in the subconscious mind and perhaps that can boost performing it at some level. But it is very difficult to memorize this piece. What a great piece.
