Alterations of Autonomic Nervous System Activity in Children with Spina Bifida: A Case-Control Study

Abstract

We compared heart rate variability parameters of patients with spina bifida with those of a control group during urodynamic study to evaluate the autonomic nervous system dysfunction of spina bifida. Continuous heart rate variability parameters were recorded during 3 successive periods (P0: 2 minutes before the start of filling; P1: start of filling to the first desire to void; P2: P1 to the end of filling or the start of voiding). Children with vesicoureteral reflux who underwent video-urodynamic study were established as a control group. We included 11 patients with spina bifida and 9 controls. At baseline, patients with spina bifida had lower values of RMSSD, pNN50, and HF, while LF/HF ratio was increased (5.04 ± 4.75 vs 0.67 ± 0.42, p = 0.014). During bladder filling, LF/HF values increased in the control group (P0 0.67 ± 0.42 vs P1 0.89 ± 0.34 vs P2 1.21 ± 0.64, p = 0.018) while it was decreased in spina bifida patients (P0 5.04 ± 4.75 vs P1 3.96 ± 4.35 vs P2 3.26 ± 4.03, p < 0.001). HF were significantly increased in spina bifida children during bladder filling (p = 0.002). In time domain, SDNN was increased only in control group during bladder filling. Parasympathetic activity domains were decreased in children with spina bifida at baseline. During the bladder filling phase, parasympathetic activity increased with fixed sympathetic activity in spina bifida group while the control group demonstrated a shifted balance toward sympathetic preponderance at the end of bladder filling. These findings may be related to the pathophysiology of neurogenic bladder in spina bifida.