Measuring the rate of progression in Friedreich ataxia: implications for clinical trial design.
Friedman LS, Farmer JM, Perlman S, Wilmot G, Gomez CM, Bushara KO, Mathews KD, Subramony SH, Ashizawa T, Balcer LJ, et al. Mov Disord. 2010 Mar 15; 25(4):426-32.