Electrical Intramuscular Stimulation in Osteoarthritis Enhances the Inhibitory Systems in Pain Processing at Cortical and Cortical Spinal System

Maria da Graca-Tarragó; Alícia Deitos; Aline Patrícia Brietzke; Iraci L S Torres; Luciana Cadore Stefani; Felipe Fregni; Wolnei Caumo

doi:10.1111/pme.12930

Electrical Intramuscular Stimulation in Osteoarthritis Enhances the Inhibitory Systems in Pain Processing at Cortical and Cortical Spinal System

Pain Med. 2016 May 1;17(5):877-891. doi: 10.1111/pme.12930. Epub 2015 Sep 23.

Authors

Maria da Graca-Tarragó^{1

2}, Alícia Deitos^{1

2}, Aline Patrícia Brietzke^{1

2}, Iraci L S Torres^{1

3}, Luciana Cadore Stefani^{1

2

4

5}, Felipe Fregni⁶, Wolnei Caumo^{1

2

4

7}

Affiliations

¹ Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal Do Rio Grande Do Sul (UFRGS), Porto Alegre, Brazil.
² Laboratory of Pain and Neuromodulation at HCPA, Porto Alegre, Brazil.
³ Pharmacology Department, Instituto De Ciências Básicas Da Saúde, UFRGS, Porto Alegre, Brazil.
⁴ Surgery Department, School of Medicine at UFRGS, Porto Alegre, Brazil.
⁵ Anesthesia and Perioperative Pain Medicine at Hospital De Clínicas De Porto Alegre (HCPA), Porto Alegre, Brazil.
⁶ Department of Physical Medicine and Rehabilitation Boston, Harvard Medical School, Boston, Massachusetts, USA.
⁷ Pain and Palliative Care Service at Hospital De Clínicas De Porto Alegre (HCPA), Porto Alegre, Brazil.

PMID: 26398594
DOI: 10.1111/pme.12930

Abstract

Objective: To determine if in knee osteoarthritis (KOA), one session of active electrical intramuscular stimulation (a-EIMS) compared with sham causes an effect on the motor cortex excitability parameters [motor evoked potential (MEP; the primary outcome), short intracortical inhibition (SICI), intracortical facilitation (ICF) and cortical silent period (CSP)] and pain measurements [pain pressure threshold (PPT); visual analog scale (VAS) and change in numerical pain scale (NPS_0-10 ) during the conditioned pain modulation (CPM)-task]. This study also set out to determine if serum brain-derived neurotrophic factor (BDNF) mediates the effect of treatment on the cortical spinal system as assessed by MEP and PPT.

Design: Randomized clinical trial.

Subjects and methods: Women with KOA, 50-75-years old received a 30-min session of either sham (n = 13) or a-EIMS (n = 13) with 2 Hz. The pain measures and excitability parameters were measured before and immediately after a-EIMS or sham.

Results: The a-EIMS group compared with sham decreased the MEP by 31,67% [confidence interval (CI) 95%, 2.34-60.98]. For the secondary outcomes, the a-EIMS reduced the ICF and increased the CSP but not changed the SICI. The a-EIMS improved the pain reported on VAS, the PPT, and the score of the NPS (0-10) during the CPM-task The BDNF was negatively correlated with the PPT (r = -0.56).

Conclusions: The serum BDNF revealed an inverse relationship with PPT independent of the treatment group. These results suggest that a-EIMS enhanced the corticospinal inhibitory systems in cortical and infracortical pain processing sites most likely by bottom-up regulation mechanisms.

Keywords: Brain-Derived Neurotrophic Factor; Conditioned Pain Modulation; Intramuscular Stimulation; Osteoarthritis; Pain Pressure Threshold; Transcranial Magnetic Stimulation.

Wiley Periodicals, Inc.