Preventing Chronification of Phantom Limb Pain Through Mirror Therapy in Conjunction With tDCS

Background: Most amputees experience phantom limb pain (PLP), for years after amputation. Virtually all PLP research to date has focused on the mechanisms of chronic PLP, ignoring the mechanisms of chronification. This research project will focus on combined neuromodulatory interventions of mirror therapy (MT) and trans direct-cranial stimulation (tDCS), applied for the first time at the acute state of PLP, with an aim to prevent its chronification and chronicity. In PLP, maladaptive plasticity associated with sensory deafferentation following an amputation is one of the contributors for excessive pain. MT is a well-accepted yet limited option, which is thought to counterbalance abnormal plasticity. tDCS is an emerging approach believed to affect the membrane potential and activity threshold of cortical neurons. tDCS analgesic effectiveness, however, is mild and short, rendering it a noneffective stand-alone treatment. The researchers' objectives are to investigate whether the combined therapy of MT and tDCS will prevent chronic PLP and improve its related clinical characteristics. In addition, the researchers will investigate the behavioral manifestations effects of the combined treatment. The investigators expect that the combined treatment applied at the acute stage of PLP will have synergistic effects on PLP intensity and thus avert its chronification. In addition, it will reduce phantom sensations, and negative affect, and will improve the sense of body ownership and agency and endogenous inhibition efficiency. Research design: This randomized-controlled double-blinded study will be held at Israel's 3 largest rehabilitation centers. The study consists of 3 randomized patient arms (36 in each): (1) no-intervention, natural-course group; (2) MT + sham tDCS; (3) MT + real tDCS. MT and tDCS neuromodulatory interferences will be self-administered and consist of 20 sessions, completed during 4 weeks. The researchers outcome measures include: primary outcome: pain intensity, network-related behavioral markers, and amputation-related clinical characteristics. The data gathered will be collected at 5 timepoints. Research novelty and innovation: The researchers proposed model will provide insights on the prevention of PLP and, potentially, other neurological pathologies involving the dysfunction of sensory systems and integration and body perception.