Analgesic efficacy of APS (Action Potential Simulation). Pilot study of the patients with chronic pain due to musculoskeletal disorders

Background and aims. Pain in musculoskeletal disorders is common medical problem, however frequently difficult to treat. That is why different methods of physical therapies have been tried with the controversial results. APS-therapy (Action Potential Simulation) falls under the broad definition of MET (Microcurrent Electrical Stimulation). MET may be a useful treatment for many pain-related disorders, providing fast relief of symptoms. The aim of this pilot clinical study was to investigate the analgesic efficacy of APS-therapy in chronic pain due to musculoskeletal disorders. Methods. The study involved 12 patients with musculoskeletal disorders who suffered from chronic pain. Each patient received treatment for 3 weeks’ time. APS-therapy was administered for a period of 16 minutes, 5 times a week. Treatment was given by portable unit, that generated an APS waveform (monophasic, pulse width 800 ms, frequency 150 Hz and intensity 0.5–1.5 mA). NRS (Numerical Rating Scale) evaluation was performed for 3 days of pre-treatment period, before each treatment which reflected the pain situation of the previous 24 h, and once daily for 2 weeks after treatment. Results. The initial mean NRS in pre-treatment period was 5.53 (SD = 1.94), decreased after APS-therapy to 3.45 (SD = 1.4) (p = 0.002) and even more to 2.56 (SD = 1.23) in the post-treatment period (p = 0.0003). Mean pain intensity decreased significantly after 11 sessions and remained on the same level up to 2 weeks of post-treatment observation. Conclusion. APS-therapy may be an effective method of nonpharmacological treatment of chronic pain in muscoskeletal disorders.