Lower disability (NDI < 18.5) was another prognostic variable indicating a greater likelihood of a positive response to physical therapy. Greater disability has been previously identified as a negative prognosis factor for patients with whiplash 63,64 or neck pain. 65 The fact that disability perceived in the neck would appear as predictor variable in women with TTH further supports the relevance of the cervical spine in the responsiveness of headache patients to physical therapy interventions. The relevance of the neck in TTH is also supported by the fact that a greater mobility in rotation (>69°) appeared as other prognostic variable. Nevertheless, the role of reduced neck mobility is debatable for the clinical course of TTH.