Migraine co-existing tension-type headache and neck pain : Validation of questionnaires

Background and aim: Migraine often includes co-existing tension-type headache (TTH) and neck pain (NP). Multiple headache questionnaires assessing headache impact have been described previously; however, none of the existing questionnaires have been designed to cover migraine with co-existing TTH and NP. Therefore a new questionnaire was developed to measure these co-morbidities. The aim was to determine face and content validity of the newly developed questionnaire, "Impact of Migraine, Tension-Type Headache and Neck Pain" (impact M-TTH-NP) and to determine face and content validity of the International Physical Activity Questionnaire (IPAQ short form), Migraine-Specific Quality of Life Questionnaire (MSQ v. 2.1), WHO-Five Well-Being Index (WHO-5), Major Depression Inventory (MDI) and Neck Disability Index (NDI) not yet validated in this target population. Material and methods: The new multi-dimensional questionnaire "Impact M-TTH-NP" cover pain, triggers, psychosocial, socioeconomic and work related aspects, based on a four-week recall period. The items are rated on an 11-point numeric rating scale with the end points 0 = no impact and 10 = most imaginable impact. Face validity was assessed by migraine patients with co-existing TTH and NP. They were recruited between September 2012 and March 2013 from a tertiary referral headache centre. Nine women with a mean age of 38 years participated in group interviews. The questionnaires were reviewed for relevance and meaningfulness. Content validity was assessed by 13 headache experts. They had worked with headache diseases for an average of 9 (range, 2-38) years. Experts were recruited between August 2012 and October 2012. Nine medical doctors, two physical therapists, one headache nurse and one psychologist (eight women and five men, mean age of 42 years) participated. The experts rated each item of the questionnaires using a four-point Likert scale with the end points 1 = not relevant and 4 = highly relevant. The quantitative measurement of content validity was calculated by the item-level content validity index (I-CVI) and the scale-level content validity average method (S-CVI/Ave). The average deviation (AD) index was used as a measure of interrater agreement. Results: Impact M-TTH-NP showed acceptable face validity. Of 78 items twelve were revised and one was added based on group interviews and expert review. Seventy-two items (92%) obtained I-CVI. ≥ 0.78 (range 0.78-1.00) indicating excellent content validity, 71 items (91%) obtained acceptable AD index. Nine items did not meet either the limit for excellent I-CVI and/or acceptable AD index. The overall S-CVI/Ave was 0.92 indicating an excellent content validity. In addition, four of the five additional questionnaires showed acceptable face validity (MSQ, WHO-5, MDI and NDI) and three showed excellent content validity (WHO-5, MDI and NDI) for patients suffering from migraine and co-existing TTH and NP. Conclusions and implications: The impact M-TTH-NP questionnaire showed acceptable face validity and excellent content validity and may be useful when evaluating treatment effect in this target group. The new impact M-TTH-NP questionnaire in combination with the additional questionnaires that together assess pain, triggers, psychosocial and socioeconomic aspects may provide a deeper understanding of the complexity of migraine with co-existing TTH and NP