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Background Content validity, the proper reflection of the concept to be measured, is yet unknown for the Credibility and Expectancy Questionnaire ( CEQ). It is frequently used in pain rehabilitation because treatment expectancy is influential on the outcome. Objective To test and improve the content validity of the CEQ in a sample of patients with chronic pain in different phases of their treatment. Methods A qualitative observational study design using the Three-Step Test-Interview method was used. Therein, data collection, analyses, and adaptations occur iteratively. Results Seventeen patients with chronic pain in different stages of treatment participated through convenience sampling from the mother sample of a randomized controlled trial. The main study parameter is content validity, which is defined as (1) interpretations and responses of the participants and (2) the identification of response problems operationalized, and resulting in changes in the CEQ. For patients waiting for treatment, the written instruction of the CEQ allowed different interpretations. After changing the instructions, the CEQ became an easy-to-understand and content-valid questionnaire. For patients who had already undergone treatment, changes regarding time frame and recall period were necessary to overcome interpretation and response problems to the CEQ. Discussion After small changes, the CEQ appeared to be a content-valid measurement instrument for patients waiting for treatment. However, for patients who had already undergone treatment, the content validity of the CEQ was less, and considerable changes were necessary. [ABSTRACT FROM AUTHOR]

Background Evidence for effectiveness of transcutaneous electrical nerve stimulation ( TENS) is still inconclusive. As heterogeneity of chronic pain patients might be an important factor for this lack of efficacy, identifying factors for a successful long-term outcome is of great importance. Methods A prospective study was performed to identify variables with potential predictive value for 2 outcome measures on long term (6 months); (1) continuation of TENS, and (2) a minimally clinical important pain reduction of ≥ 33%. At baseline, a set of risk factors including pain-related variables, psychological factors, and disability was measured. Results In a multiple logistic regression analysis, higher patient's expectations, neuropathic pain, no severe pain (< 80 mm visual analogue scale [ VAS]) were independently related to long-term continuation of TENS. For the outcome 'minimally clinical important pain reduction,' the multiple logistic regression analysis indicated that no multisited pain (> 2 pain locations) and intermittent pain were positively and independently associated with a minimally clinical important pain reduction of ≥ 33%. Conclusion The results showed that factors associated with a successful outcome in the long term are dependent on definition of successful outcome. [ABSTRACT FROM AUTHOR]