Development of Wearable Pulsed Electromagnetic Field Device and Its Application to Autonomic Nervous System Regulation

The autonomic nervous system (ANS) plays an important regulatory role in human health. Dysautonomia can lead to many diseases. In recent studies, the use of pulsed electromagnetic field (PEMF) therapy has gained great attention for regulating the balance of ANS. PEMF therapy does not require direct contact with the user's body. It is a noninvasive, noncontact, and nonthermal treatment, which does not cause damage to the skin with long-time use. However, current PEMF devices are bulky owing to the large size of magnetic coil needed to generate sufficient magnetic strength for stimulation purpose. This study introduces a multilayer PEMF device fabricated using flexible printed circuit boards (FPCBs). By employing a concentric winding method, we have enhanced the magnetic field strength, resulting in a flexible, thin, lightweight, and high-intensity magnetic field PEMF system. The PEMF system has been applied to abdominal stimulation in order to regulate the ANS balance during posture-induced sympathetic/parasympathetic changes in tilt-table tests. The PEMF stimulation showed a significant improvement in the regulation of ANS balance. Comparing the PEMF with non-PEMF conditions, the spectral heart rate variability (HRV) indices low frequency (LF), high-frequency (HF), and LF/HF ratio were 62.02±19.35 versus 71.17±14.34 , 37.98±19.35 versus 28.83±14.34 , and 2.62±2.41 versus 4.03±3.96 , respectively, demonstrating the effectiveness of PEMF stimulation in ANS regulation. The proposed wearable PEMF device has good wearability and can be integrated with clothing, which enables the long-term stimulation in future human studies.