37 Autonomic nervous system response to a solid meal in healthy children: its relation to gastric myoelectrical activity

Abstract

Electrogastrogram (EGG) is a measurement of gastric electrical activity using cutaneous electrodes. Autonomic nervous function is an important modulator of gastric activity, but little is known regarding its relation with the EGG parameters. The aims of this study were to investigate the patterns of myoelectrical and autonomic activities both in the fasting and in the fed state and their correlation in healthy children.Methods: Simultaneous recordings of EGG and electrocardiogram were performed in 28 healthy children (13 M, 15 F, mean age: 12.4 years, range: 8–17) for 30 min in the fasting state and 60 min after a solid test meal. Spectral analysis was performed to compute EGG parameters and their postprandial changes. The autonomic activity was assessed based on spectral analysis of the heart rate variability (HRV) signal which was derived from the electrocardiogram. Data are presented as mean ± SE.Results: The solid meal resulted in a postprandial increase in the EGG dominant frequency (2.92 ± 0.08 cpm vs. 3.16 ± 0.07 cpm, P < 0.05), dominant power (46.9 ± 0.8 dB vs. 53.7 ± 1.5 dB, P < 0.05), and percentage of normal slow waves (81.9 ± 2.0% vs. 89.0 ± 2.0%, P < 0.05). Spectral analysis of HRV revealed that sympathetic activity primarily associated with power in the low‐frequency band of HRV (LF) was increased in the postprandial state (0.34 ± 0.02 vs. 0.43 ± 0.03, P < 0.05). The parasympathetic activity primarily associated with power in high‐frequency band of HRV (HF) was significantly higher in the fasting state (0.66 ± 0.02 vs. 0.58 ± 0.03, P < 0.05). The sympathovagal balance associated with the LF‐to‐HF ratio was much higher in the postprandial state (0.56 ± 0.05 vs. 0.90 ± 0.13, P < 0.05). Moreover postprandial LF was positively and HF was negatively correlated with the postprandial increase in EGG dominant power (r = 0.39; P = 0.04, respectively).Conclusions: The solid meal resulted in a significant increase in EGG dominant frequency, dominant power and percentage of normal slow waves as well as sympathovagal balance in healthy children, suggesting that both vagal and sympathetic pathways are involved in modulation of gastric myoelectrical activity.