"Power and Sample Size Program" was used to calculate sample size. It was determined by considering a previous study which calculated minimal detectable change of Berg Balance Scale (BBS) for stroke patients(20). According to this study to the response within each subject group was normally distributed with standard deviation 7.87 and minimal detectable change was found 10% for BBS. It was calculated that 15 participants were needed in each group with probability (power) 0.8 and 0.016 alpha level computed by Bonferroni adjustment.