Analysis of secondary endpoints
NRS, pain
The mean NRS score on D8 will be compared between the active tDCS arm and the sham tDCS arm using a mixed linear model in order to take stratification factors into account. This analysis will also be adjusted for analgesic consumption based on the MQS score.The immediate efficacy of tDCS on pain intensity will be compared between the two arms using a mixed linear model with the pre- and post-tDCS difference of the NRS score as the variable to be explained. This model will take repeated measures per patient into account.The response rate will be compared between the two arms by a mixed logistic model in order to take stratification factors into account.The residual analgesic effect on D14 and D21 will be studied using a mixed linear model in order to take stratification factors into account. This analysis will also be adjusted for analgesic consumption.The course of quality of life assessed by the BPI, ESAS, HADS and STAI-Y between D0 and D7 will be compared between the two arms by a mixed linear model in order to take stratification factors into account.Analgesic consumption, evaluated by the MQS questionnaire, will be compared between the two arms using a mixed linear model.Complementary analysis of the primary efficacy endpoint could be conducted on a per protocol population including all patients of the mITT population not presenting any major protocol violations. These major violations will be defined in the analysis plan before locking the database.