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J Rehabil Med 2019; 51: 622–623 LETTER TO THE EDITOR COMMENTARY ON: ”COMBINED TRANSCRANIAL DIRECT CURRENT STIMULATION AND BREATHING-CONTROLLED ELECTRICAL STIMULATION FOR MANAGEMENT OF NEUROPATHIC PAIN AFTER SPINAL CORD INJURY” We read with interest the article by Li et al. on the use of combined transcranial direct current stimulation (tDCS) and breathing-controlled electrical stimulation (Bre-Estim) for management of neuropathic pain after spinal cord injury (1, 2). The authors present a well-designed study with interesting findings, which concludes that Bre-Estim has an immediate analgesic effect in comparison with active tDCS. In addition, they concluded that there was no additive effect of a combined tDCS and BreEstim intervention for neuropathic pain after SCI. However, we have some difficulty in interpreting their findings (3). First, the methodology is unclear. The treatment protocol states that an intervention comprising 20 min active tDCS followed by 20 min BreEstim was given, and, to assess pain, a visual analogue scale (VAS) was used as outcome measure after 10 min tDCS and 10 min BreEstim. The authors did not specify the time interval between interventions, and why the pain level was assessed after 10 mins. In order to check the im- mediate effect the pain level should have been assessed immediately after the intervention (1). Secondly, we have some doubts about the study design. The methodology section reports that this is a single-blinded, single-centre, sham-controlled cross­ over design. However, if this is a sham-controlled design why did the study deviate towards an experi- mental design? A pre-post control group design should have been used. The authors stated in the clinical trial registry that they hypothesized that a single session of combined BreEstim and tDCS would produce an analgesic ef- fect; however, in the main article it was stated that the intervention was given for at least 3 days. In the trial registration, they stated that participants would be randomized, but the authors did not mention randomi- zation in the study (2). The outcome measures used are not clear; secondary outcome measures are not explained in the study, but they are mentioned in the trial registration. It is not stated how the authors conformed the neuropathic pain in patients with SCI. The primary outcome measure, VAS, cannot measure the quality of pain. Rather than a VAS, a neuropathic pain scale (NPS), which can measure treatment outcome and pain descriptors and can differentiate between neuropathic and chronic pain should have been used (4). The characteristics of participants and neuropathic pain mentioned in Table I are not clear. Neuropathic pain characteristics are mentioned among 12 partici- pants, of which 5 have neuropathic pain in the lower limbs, 6 have neuropathic pain in the upper limbs, and in 1 patient the region of pain is not mentioned. In addition, the level of injury is not stated. The par- ticipants should have had neuropathic pain symptoms in the upper limb, since BreEstim is used specifically for median nerve stimulation in the upper limb (4); it is not clear why the author recruited patients with neuropathic pain in the lower limb. The methodology states that the total number of electrical stimuli given during the BreEstim interven- tion was 160, with sufficient rest during treatment and a duration of approximately 20 min. It is not clear why the term “approximately” was used for treatment dura- tion; the duration of treatment should be specific (1). The statistical analysis section does not explain why the non-parametric test was not performed, as the primary outcome measure is an ordinal scale. Finally, it is not explained why repeated measure analysis of variance (ANOVA) was used instead of a Friedman test for data analysis (5). We would be interested in the authors’ thoughts on these comments. Accepted Jun 5, 2019; Epub ahead of print Jun 24, 2019 Adarsh Kumar Srivastav, Nidhi Sharma and Sarita Khadayat From the Physiotherapy, Maharishi Markandeshwar Institute of Physiotherapy and Rehabilitation 133207 Ambala, India. E-mail: [email protected] RESPONSE TO LETTER TO THE EDITOR FROM SRIVASTAV ET AL. We thank the authors for their sincere interest in our study. Point-by-point clarification is provided here regarding their concerns about the study design and methodology. The treatment protocol was illustrated in Fig. 1. The protocol included a 20-min tDCS (active or sham), followed by a 20-min BreEStim. As shown in Fig. 1, the interval between tDCS and BreEStim was 10 min. This is an open access article under the CC BY-NC license. www.medicaljournals.se/jrm doi: 10.2340/16501977-2576 Journal Compilation © 2019 Foundation of Rehabilitation Information. ISSN 1650-1977