Objective: To analyze the correlation between changes in pain-related outcomes and neurophysiological cortical measures following transcranial direct current stimulation (tDCS) in Parkinson’s disease (PD).
Background: Pain is a common and disabling non-motor symptom of PD that significantly impairs quality of life. A recent study conducted by our research group, showed that anodal tDCS over M1 significantly reduced PD-related pain, improved widespread mechanical hyperalgesia, and enhanced descending pain inhibition. To determine whether pain improvements following tDCS are associated with changes in motor neurophysiological markers may help clarify shared mechanisms underlying motor and analgesic effects in PD
Method: A secondary analysis was performed on data obtained from 16 participants (9 women; mean age 60.18 ± 11.05 years) enrolled in a previously controlled trial. The active group received 10 consecutive daily 20-minute sessions of anodal tDCS over M1 at 2 mA. Assessments were performed at baseline, post-intervention, and at 15-day follow-up. Pain-related outcomes included the King’s Parkinson’s Disease Pain Scale (KPPS), Brief Pain Inventory (BPI), pain expansion, temporal summation (TS), and conditioned pain modulation (CPM). Motor cortical measures were obtained using transcranial magnetic stimulation and included resting motor threshold (RMT), active motor threshold (AMT), and cortical silent period (CSP).
Results: Two-way ANOVA showed significant improvements in KPPS, pain expansion, and CPM in favor of active tDCS compared with sham tDCS, whereas no significant changes were observed in motor cortical variables. For pre–post changes, a significant moderate correlation was found between BPI pain intensity and the left CSP (r = 0.577; p = 0.024). At 15 days, significant moderate correlations were identified between BPI pain intensity and interference scores and the left CSP (r = 0.622; p = 0.013; r = 0.740; p = 0.002, respectively), between pain expansion and the left CSP (r = −0.542; p = 0.037), and between CPM and the left AMT (r = 0.657; p = 0.008).
Conclusion: Associations between pain-related and motor cortical variables were inconsistent and did not support a clear relationship between pain changes and cortical excitability. Pain improvements following tDCS may therefore involve subcortical rather than cortical mechanisms.
References: 1. González-Zamorano, Y., Sánchez-Cuesta, F. J., Moreno-Verdú, M., Arroyo-Ferrer, A., Fernández-Carnero, J., Chaudhuri, K. R., … & Romero, J. P. (2024). TDCS for parkinson‘s disease disease-related pain: A randomized trial. Clinical Neurophysiology, 161, 133-146.
To cite this abstract in AMA style:
A. Megía-García, Y. González Zamorano, F. Sanchez Cuesta, J. Gómez Soriano, J. Romero Muñoz. Pain relief beyond motor cortex modulation: clinical–neurophysiological dissociation after M1-tDCS in Parkinson’s disease [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/pain-relief-beyond-motor-cortex-modulation-clinical-neurophysiological-dissociation-after-m1-tdcs-in-parkinsons-disease/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/pain-relief-beyond-motor-cortex-modulation-clinical-neurophysiological-dissociation-after-m1-tdcs-in-parkinsons-disease/