Effects of Combined and Alone Transcranial Motor Cortex Stimulation and Mirror Therapy in Phantom Limb Pain: A Randomized Factorial Trial.

Phantom limb pain (PLP) is a frequent complication in amputees, which is often refractory to treatments. We aim to assess in a factorial trial the effects of transcranial direct current stimulation (tDCS) and mirror therapy (MT) in patients with traumatic lower limb amputation; and whether the motor cortex plasticity changes drive these results. In this large randomized, blinded, 2-site, sham-controlled, 2 × 2 factorial trial, 112 participants with traumatic lower limb amputation were randomized into treatment groups. The interventions were active or covered MT for 4 weeks (20 sessions, 15 minutes each) combined with 2 weeks of either active or sham tDCS (10 sessions, 20 minutes each) applied to the contralateral primary motor cortex. The primary outcome was PLP changes on the visual analogue scale at the end of interventions (4 weeks). Motor cortex excitability and cortical mapping were assessed by transcranial magnetic stimulation (TMS). We found no interaction between tDCS and MT groups (F = 1.90, P = .13). In the adjusted models, there was a main effect of active tDCS compared to sham tDCS (beta coefficient = -0.99, P = .04) on phantom pain. The overall effect size was 1.19 (95% confidence interval: 0.90, 1.47). No changes in depression and anxiety were found. TDCS intervention was associated with increased intracortical inhibition (coefficient = 0.96, P = .02) and facilitation (coefficient = 2.03, P = .03) as well as a posterolateral shift of the center of gravity in the affected hemisphere. MT induced no motor cortex plasticity changes assessed by TMS. These findings indicate that transcranial motor cortex stimulation might be an affordable and beneficial PLP treatment modality.

STRATEGIES TO ENHANCE RECRUITMENT METHODS IN PHANTOM LIMB PAIN CLINICAL TRIALS.

Phantom Limp Pain (PLP) was first described in 1551. To date, its mechanisms and novel interventions remain mostly untested. Only limited conclusions can be drawn from few and small randomized clinical trials (RCTs) on PLP. In this scenario, recruitment strategies are crucial in order to overcome inherent challenges to recruit PLP subjects for clinical trials. Although there are many methods to enhance recruitment and also retention, in this article we discuss these methods based on a common topic: dissemination. We summarize and discuss 10 strategies of recruitment related to the dissemination of information based on the notion that an increase in trial awareness may lead to both increased recruitment and also increased external generalizability. In addition, in our discussion we included insights based on our experience recruiting PLP patients for our large NIH-sponsored clinical trial. Although specific regulatory considerations need to be considered when choosing the methods of recruitment, which may vary across different countries and Institutional Review Boards (IRBs), these strategies may be applicable to most of research settings.