2.7. Outcome Measures
chronic pain, headaches, pain
CHRONIC PAIN
The participants' pain intensity was measured on a 10-cm visual analog scale (VAS) with zero (0) at one end and ten (10) at the other, signifying no pain and the worst pain possible, respectively. The participants were instructed to place a mark between 0 and 10 on the VAS scale to indicate their actual amount of pain during the week/night. The VAS has been shown to be a valid and reliable instrument with the least detectable change for measuring headaches and other chronic pain [