Fig. 4

Correlation analysis between clinical improvement and IDAP changes. At the group level, the reduction in IDAP value was positively correlated with the reduction of day of headache in the follow-up month. Positive IDAP values indicate that the T1 measurement was smaller than the first. The calculation for IDAP change was: IDAP change = IDAP(T0)-IDAP(T1). On the other hand for headache days calculation was: Headache reduction = days(T2)-days(T0)