Pain Modulation Index is a questionnaire that was developed in English for the assessment of chronic pain for qualities consistent with central sensitization. The English version of the questionnaire was translated into Turkish by two physicians than back translated into English by two separate bilingual translators. Initially 10 volunteers were asked to answer this first version of the questionnaire and report any difficulties in understanding the items. Their feedback was used to give the questionnaire its final shape. For the validation stage, patients that were diagnosed as having chronic non-cancer pain with more than 3 months duration were enrolled into the study. They answered the questions twice, 15 days apart. In addition to the Turkish version of the Pain Modulation Index, on the first visit, they were also asked to answer Pain Detect and Central Sensitization Inventory. Their answers were analysed to assess the validity and reliability of the Turkish version of Pain Modulation Index.
In order to assess the validity and reliability of the Turkish version of Pain Modulation Index, 125 volunteers with chronic pain were enrolled in the study. Test and re-test method was used to assess reliability and correlation analyses with Pain Detect, visual analog scale pain and central sensitization inventory scores were used to assess validity of the questionnaire. Turkish version of the Pain Modulation Index was found to be a valid and reliable tool for evaluating chronic pain.