Higuchi Fractal Dimension of Heart Rate Variability During Percutaneous Auricular Vagus Nerve Stimulation in Healthy and Diabetic Subjects

• Published in: Frontiers in physiology Vol. 9; p. 1162
• Main Authors: Gomolka, Ryszard S., Kampusch, Stefan, Kaniusas, Eugenijus, Thürk, Florian, Széles, Jozsef C., Klonowski, Wlodzimierz
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 21.08.2018
• Subjects: autonomic nervous system; diabetes; heart rate variability; Higuchi fractal dimension; Physiology; vagus nerve stimulation; vagus nerve stimulation; Higuchi fractal dimension; autonomic nervous system; heart rate variability; diabetes
• ISSN: 1664-042X; 1664-042X
• DOI: 10.3389/fphys.2018.01162

Analysis of heart rate variability (HRV) can be applied to assess the autonomic nervous system (ANS) sympathetic and parasympathetic activity. Since living systems are non-linear, evaluation of ANS activity is difficult by means of linear methods. We propose to apply the Higuchi fractal dimension (HFD) method for assessment of ANS activity. HFD measures complexity of the HRV signal. We analyzed 45 RR time series of 84 min duration each from nine healthy and five diabetic subjects with clinically confirmed long-term diabetes mellitus type II and with diabetic foot ulcer lasting more than 6 weeks. Based on HRV time series complexity analysis we have shown that HFD: (1) discriminates healthy subjects from patients with diabetes mellitus type II; (2) assesses the impact of percutaneous auricular vagus nerve stimulation (pVNS) on ANS activity in normal and diabetic conditions. Thus, HFD may be used during pVNS treatment, to provide stimulation feedback for on-line regulation of therapy in a fast and robust way.