*2.3. Calculation of the Sample Size*

G\*Power software was employed for the sample size calculation in order to measure the difference between the chronic non-insertional AT group and control group using the CFP thickness (mm) variable of a pilot study (*n* = 20) that was divided into two groups (mean ± SD): 10 subjects with chronic non-insertional AT (7.27 ± 1.97), and 10 subjects for the healthy group (8.51 ± 0.51). For the sample size calculation, a power of 0.80, an α error of 0.05 and an effect size of 0.86 with a one-tailed hypothesis were employed. In conclusion, a sample of 36 was calculated. Nevertheless, we could include a sample of 143 individuals.
