1. Introduction
rheumatoid arthritis, low back pain, seizures, osteoarthritis, hypoactive, painless, chronic musculoskeletal pain, pain, shoulder pain, chronic neck pain, hyperactive
RHEUMATOID ARTHRITIS, AUTONOMIC IMBALANCE, OSTEOARTHRITIS, MUSCULOSKELETAL DISORDERS, SYNDROMES, HEART, DISEASES, AUTONOMIC DYSREGULATION
Heart rate variability (HRV) analysis has emerged as a simple and non-invasive technique to indirectly evaluate the autonomic nervous system (ANS), and it is considered a sensible and advanced index of health status. Pulsed electromagnetic fields (PEMFs) are widely used in clinical settings for improving the health status of individuals with chronic musculoskeletal pain. The aim of the present single-blind, randomized, placebo-controlled parallel pilot study was to investigate the acute effect of a single session of PEMFs stimulation by a PAP ion magnetic induction (PAPIMI) device on ANS activity, as measured by HRV, in patients with chronic musculoskeletal pain, and compare such effect with that induced by a sham (control) PAPIMI inductor. Thirty-two patients were randomized into two groups: PAPIMI intervention (PAP) (n = 17) and sham PAPIMI intervention (SHAM-PAP) (n = 15). HRV was assessed before and following the interventions. The PAP group showed a significant increase in all values of the time-domain parameters (SDNN, RMSSD, NN50, and pNN50) and the HF component of HRV, suggesting a parasympathetic effect. In contrast, the SHAM-PAP group showed no significant differences in all HRV indices following the intervention. Preliminary findings suggested that PAPIMI inductor could influence ANS activity and provided initial evidence of the potential physiological response induced by the PAPIMI device.The autonomic nervous system (ANS) plays a critical role in the regulation and coordination of the physiological processes in human biological organisms, and individual differences in autonomic balance have long been associated with health and pathological conditions [The ANS is assumed to be composed of two major antagonistic subsystems that commonly act in dynamic balance: the sympathetic branch, involved in regulating energy mobilization, and the parasympathetic branch, implicated in vegetative and restorative functions [The dynamic balance between distinct components of the ANS can be threatened and altered by metabolic (inner) and environmental (external) stimuli, which may cause a condition of autonomic imbalance. Specifically, the loss of autonomic balance, in which one branch of the ANS prevails over the other, is characterized by a lack of dynamic adaptability and of the health of the organism. A substantial amount of empirical evidence indicates that a host of pathological conditions and diseases are associated with autonomic dysregulation, in which, typically, the sympathetic system is hyperactive and the parasympathetic system is hypoactive [Among the methods adopted to assess ANS function, heart rate variability (HRV) analysis has emerged as a simple and noninvasive technique to indirectly evaluate the autonomic activity, representing one of the most important quantitative markers of ANS balance/imbalance [As regards the link to pathological conditions, it was reported that ANS imbalance is associated with chronic musculoskeletal pain. This common physiological disfunction is defined as a pain that affects bones, muscles, ligaments, tendons, and even nerves; it comprises a number of different pain syndromes such as chronic neck pain, shoulder pain, low back pain, and also pain associated with osteoarthritis and rheumatoid arthritis [Different non-pharmacologic approaches are available for relieving the pain associated with musculoskeletal disorders [The PAP ion magnetic induction (PAPIMI) device is a certified and approved medical instrument that belongs to the large family of PEMFs. This device provides a non-invasive, painless, contact-free ion-induction therapy that was shown to be effective for the treatment of refractory seizures [Therefore, the aim of the present single-blind, randomized, placebo-controlled parallel pilot study was to investigate the acute effect of a single-session treatment of PEMFs stimulation by PAPIMI inductor on ANS balance, as measured by HRV, in patients suffering from chronic musculoskeletal pain, and compare such effect with that induced by a sham (control) PAPIMI inductor. We hypothesized that PAPIMI intervention, as compared to the sham one, could induce a more effective parasympathetic response, which would result in an increased HRV.