Daniela Regina Brandão Tavares1, Jane Erika Frazao Okazaki2, Marcia Valéria de Andrade Santana3, Ana Carolina Pereira Nunes Pinto4, Karina Kuraoka Tutiya5, Fernanda Martins Gazoni6, Camila Bonin Pinto7, Fania Cristina Santos8, Felipe Fregni9, Virginia Fernandes Moça Trevisani10. 1. Departament of Geriatrics and Gerontology, Federal University of São Paulo, São Paulo, SP, Brazil; Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, São Paulo, SP, Brazil. Electronic address: daniela74_tavares@hotmail.com. 2. Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, São Paulo, SP, Brazil. Electronic address: erikafrazao@gmail.com. 3. Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, São Paulo, SP, Brazil. Electronic address: lella-andrade@hotmail.com. 4. Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, São Paulo, SP, Brazil; Department of Physical Therapy, University of Pittsburgh, Fullbright Program, USA. Electronic address: anacarolinapnp@hotmail.com. 5. Departament of Geriatrics and Gerontology, Federal University of São Paulo, São Paulo, SP, Brazil. Electronic address: karina.tutiya@hotmail.com. 6. Departament of Geriatrics and Gerontology, Federal University of São Paulo, São Paulo, SP, Brazil; Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, São Paulo, SP, Brazil. Electronic address: fmgazoni@hotmail.com. 7. Laboratory of Neuromodulation, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. Electronic address: cboninpinto@gmail.com. 8. Departament of Geriatrics and Gerontology, Federal University of São Paulo, São Paulo, SP, Brazil. 9. Laboratory of Neuromodulation, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. Electronic address: fregni.felipe@mgh.harvard.edu. 10. Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, São Paulo, SP, Brazil; Department of Rheumatology, Santo Amaro University, São Paulo, SP, Brazil. Electronic address: vmoca@uol.com.br.
Abstract
BACKGROUND: Although evidence has indicated a positive effect of transcranial direct current stimulation (tDCS) on reducing pain, few studies have focused on the elderly population with knee osteoarthritis (KOA). OBJECTIVE: To evaluate whether tDCS reduces KOA pain in elderly individuals with a dysfunctional descending pain inhibitory system (DPIS). METHODS: In a double-blind trial, individuals ≥ 60 years with KOA pain and a dysfunctional DPIS, we randomly assigned patients to receive 15 daily sessions of 2 mA tDCS over the primary motor cortex (anode) and contralateral supraorbital area (cathode) (M1-SO) for 20 min or shamtDCS. Change in pain perception indexed by the Brief Pain Inventory (BPI) at the end of intervention was the primary outcome. Secondary outcomes included: disability, quantitative sensory testing, pain pressure threshold and conditioned pain modulation (CPM). Subjects were followed-up for 2 months. RESULTS: Of the 104 enrolled subjects, with mean (SD) age of 73.9 (8.01) years and 88 (84.6%) female, 102 finished the trial. In the intention-to-treat analysis, the active tDCS group had a significantly greater reduction in BPI compared to the sham group (difference, 1.59; 95% CI, 0.95 to 2.23; P < 0.001; Cohen's d, 0.58); and, also a significantly greater improvement in CPM-pressure in the knee (P = 0.01) and CPM-pain in the hand (P = 0.01). These effects were not sustained at follow-up. The intervention was well tolerated, with no severe adverse effects. CONCLUSION:M1-SO tDCS is associated with a moderate effect size in reducing pain in elderly patients with KOA after 15 daily sessions of stimulation. This intervention has also shown to modulate the DPIS.
RCT Entities:
BACKGROUND: Although evidence has indicated a positive effect of transcranial direct current stimulation (tDCS) on reducing pain, few studies have focused on the elderly population with knee osteoarthritis (KOA). OBJECTIVE: To evaluate whether tDCS reduces KOA pain in elderly individuals with a dysfunctional descending pain inhibitory system (DPIS). METHODS: In a double-blind trial, individuals ≥ 60 years with KOA pain and a dysfunctional DPIS, we randomly assigned patients to receive 15 daily sessions of 2 mA tDCS over the primary motor cortex (anode) and contralateral supraorbital area (cathode) (M1-SO) for 20 min or sham tDCS. Change in pain perception indexed by the Brief Pain Inventory (BPI) at the end of intervention was the primary outcome. Secondary outcomes included: disability, quantitative sensory testing, pain pressure threshold and conditioned pain modulation (CPM). Subjects were followed-up for 2 months. RESULTS: Of the 104 enrolled subjects, with mean (SD) age of 73.9 (8.01) years and 88 (84.6%) female, 102 finished the trial. In the intention-to-treat analysis, the active tDCS group had a significantly greater reduction in BPI compared to the sham group (difference, 1.59; 95% CI, 0.95 to 2.23; P < 0.001; Cohen's d, 0.58); and, also a significantly greater improvement in CPM-pressure in the knee (P = 0.01) and CPM-pain in the hand (P = 0.01). These effects were not sustained at follow-up. The intervention was well tolerated, with no severe adverse effects. CONCLUSION: M1-SO tDCS is associated with a moderate effect size in reducing pain in elderly patients with KOA after 15 daily sessions of stimulation. This intervention has also shown to modulate the DPIS.