Shaunna Smith, Ed.D. is an Assistant Professor of Educational Technology at Texas State University who I met at the Maker Ed Summit in Arizona last fall. She has been facilitating art + math makercamps for middle school girls with a focus on impacts to their efficacy and visual spatial skills. They use the Revised Purdue Spatial Visualization Tests: Visualization of Rotations (Revised PSVT:R), which can be viewed here (she had to email them directly to request a free copy from the author).
Shaunna reports, "When we used this as a pre/post-test with our participants we found an increase from 7.6 to 9.2" which seems significant. They also used a self-efficacy test designed by Usher & Pajares (2009) for middle school aged students. The final study will be out soon.
These instruments might be helpful for people who are looking for instruments for students.