IRCT20171107037306N1 IRCT 2017-12-17 Rofeideh Rehabilitation Hospital Effectiveness of attention bias modification and Trance cranial direct current stimulation on reduction of pain and attention bias. Comparison of the effectiveness of attention bias modification (ABM) with/without Trance cranial direct current stimulation (TDCS) on reduction of attention bias and severity of perceived pain in chronic low back pain patients. 2017-12-21 anticipated 60 Complete https://irct.ir/trial/27636 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Supportive, Randomization description: In this study, the subjects are randomly assigned into intervention, control, and placebo groups using random number table. Sealed non-transparent envelopes with random sequence were used to conceal random assignment. Following constructing random sequence by random table, 60 envelopes with aluminum wrappers (in order to obscure the envelopes) were prepared based on the research sample size, and each of random sequences was recorded on a card, and the cards were placed in the envelopes in order. External surface of the envelopes are numbered in the same order for preserving random sequence. Based on the order by which the qualified subjects entered to the study, the envelopes were opened and the assigned group for the subject was specified, Blinding description: First, the physician interviewed with the patients considering inclusion and exclusion criteria. Then, individuals qualified with inclusion criteria, who were content with participation in the research, were introduced to the interviewer and he conducted the primary evaluation. The subjects were then referred to the therapist and were randomly assigned into the intervention or placebo groups. After intervention, the subjects were introduced to the examiner author, and secondary evaluation was carried out. Second examiner was unaware of assignment of subjects in intervention groups. Thus, the subjects, outcome valuator (second examiner), and clinical care provider were kept blind toward the group assignments in this study. N/A chronic low back pain. Intervention 1: The second experimental group receive the attention bias modification task combined with trance cranial direct current stimulation through 5 sessions of 20 minutes. Intervention 2: placebo group receive sham Trance cranial direct current stimulation.(TDCS). Intervention 3: One of the experimental groups receives attention bias modification task by computer through 5 sessions of 20 minutes . Intervention 4: control group answer the questionnaire and dont receive any intervention. Undecided - It is not yet known if there will be a plan to make this available