545: Somatosensory Rehabilitation Combined with tDCS in Neuropathic Pain: A Randomized Controlled Trial

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Neuropathic pain , Physiotherapy (e.g. exercise, rehab), Neuromodulation (e.g. TMS, TDCS, FUS, SCS, MCS, DBS, vagus nerve stimulation), Treatment/management

Background and Aims: Neuropathic pain (NP) is characterized by maladaptive peripheral and central plasticity, frequently manifesting as static mechanical allodynia and paradoxical painful hypoesthesia. Somatosensory Rehabilitation (SR) promotes peripheral afferent reorganization, whereas primary motor cortex (M1) transcranial direct current stimulation (tDCS) modulates cortical excitability and descending inhibitory pathways. The potential synergistic interaction between these mechanisms remains insufficiently explored. Thus, the objective of this study was to investigate whether SR combined with M1 tDCS enhances somatosensory recovery and pain reduction in individuals with NP.

Methods: Randomized, controlled, double-blind clinical trial (COMEP approval: 5.953.512). Fourteen patients with clinical diagnosis of NP were included, totaling 38 affected cutaneous branches. Participants were allocated to Group A (SR + active M1 tDCS; n=20 branches) or Group B (SR + sham tDCS; n=18 branches). Interventions were delivered weekly (45 min/session) for four weeks. Outcomes included standardized allodynography (territory quantification) and the McGill Pain Questionnaire (MPQ), capturing sensory and affective dimensions. Data were analyzed using paired and independent Student’s t-tests and repeated-measures ANOVA (α=0.05). Effect size was calculated using Cohen’s d.

Results: Both groups demonstrated significant reductions in allodynic territory and total MPQ scores post-intervention (p<0.05). However, the active tDCS group showed significantly greater reductions in cartographic area and in the sensory-discriminative component of the MPQ compared to sham. The combined intervention yielded a large effect size (Cohen’s d > 1.0), indicating strong clinical relevance beyond statistical significance. The magnitude of change suggests meaningful modulation of both somatosensory processing and pain perception.

Conclusions: SR combined with M1 tDCS significantly enhances reduction of allodynia and multidimensional neuropathic pain compared to SR alone. The large effect size supports a synergistic peripheral–cortical plasticity mechanism. These findings reinforce mechanism-based multimodal rehabilitation strategies for neuropathic pain, warranting long-term investigation. Long-term follow-up studies are warranted.

References: Finnerup NB, Kuner R, Jensen TS. Neuropathic pain: From mechanisms to treatment. Physiol Rev. 2021;101(1):259–301.
Melzack R. The McGill Pain Questionnaire: Major properties and scoring methods. Pain. 1975;1(3):277–299.
Spicher CJ et al. Static mechanical allodynia is a paradoxical painful hypoesthesia. Somatosens Mot Res. 2008;25:77–92.
de Andrade Melo Knaut S et al. Static mechanical allodynia as paradoxical painful touch-evoked hypoesthesia. Douleur Analg. 2024.
Spicher CJ et al. Atlas of cutaneous branch territories for the diagnosis of neuropathic pain. Springer; 2020.
Spicher C, Murray E, Chapdelaine S, de Andrade Melo Knaut S. Méthode de rééducation sensitive de la douleur. Sauramps Médical; 2025.
Lefaucheur JP. Cortical neurostimulation for neuropathic pain: state of the art. Pain. 2016;157(Suppl 1):S81–S89.
Baptista AF et al. Latin American and Caribbean consensus on noninvasive CNS neuromodulation for chronic pain. Pain Reports. 2019;4:e692.

Presenting Author: Sibele de Andrade Melo Knaut
Submitting Author: Sibele de Andrade Melo Knaut

Senior Author: Sibele de Andrade Melo Knaut

IASP 2026 Global Year theme of Neuropathic Pain: Yes

• Jessika Mehret Fiusa: PhD - Universidade Estadual do Centro-Oeste
• Kelli Maiara Gomes da Silva: Physiotherapist - Universidade Estadual do Centro-Oeste
• Josiane Dobuchak: Physiotherapist - Universidade Estadual do Centro-Oeste
• Cintia Raquel Bim: PhD - Universidade Estadual do Centro-Oeste
• Marina Pegoraro Baroni: PhD - Universidade Estadual do Centro-Oeste