NPPB and obstructive sleep apnea syndrome: They stipulated that the decreased plasma osmolality at the end of treatment of enuretic children with rapid palatal expansion was assumed to be consequence of increased ADH level.[26] Other possible mechanisms are improved neuromuscular coordination and lesser deep phase of sleep related to a higher oxygen saturation level derived by smoother and higher nasal airflow.[23] More recently, Sans Capdevila et al. found that higher brain natriuretic peptide is secreted in cases with either obstructive sleep apnea or enuresis.