Key points are not available for this paper at this time.
Barry T. Peterson, Steven J. Clancy, Kay Champion, Jerry W. McLarty, Improving Readability of Consent Forms: What the Computers May Not Tell You, IRB: Ethics & Human Research, Vol. 14, No. 6 (Nov. - Dec., 1992), pp. 6-8
Peterson et al. (Sun,) studied this question.