LAUSR

Functional abdominal pain disorder (FAPD) is a common disorder in adolescents with an estimated prevalence of 13.5 % worldwide. It is characterized by nearly-continuous or recurrent pain localized in the abdomen but poorly related to gut function. A greater incidence of sleep disorders has been described in pediatric populations with FAPD, but no studies have characterized differences in sleep continuity and quality that may be experienced by this population. This study examines differences in sleep spindles experienced by adolescents with FAPD due to the role of sleep spindles in sleep stabilization as it relates to pain. Subjects ages 11-18 years with FAPD and age/gender matched controls were recruited and underwent prospective polysomnography (PSG). PSGs were conducted according to AASM accredited standards, scored by a registered PSG technician, and interpreted by a boarded sleep physician. Using only artifact free epochs, sleep spindles were identified and characterized using the YASA python package / A7 algorithm with selections confirmed against gold standard (manual scoring). Comparisons of FAPD and control groups were performed using t-test or Wilcoxon rank sum tests for normal and non-normally distributed data, respectively. The PSG scorers and those preforming spindle analysis were blinded to control vs study group throughout the study. The study included 21 adolescents with FAPD and 20 controls. When compared to controls, the FAPD group had an elevated arousal index (FAPD: 10.08/hr ±4.89/hr, control: 7.32/hr ±3.61/hr, p = 0.046) and a lower percentage of NREM 3 sleep (FAPD: 20.13% ±5.47%, control: 24.77% ±6.94%, p = 0.023). During NREM 2 sleep, the FAPD group had significantly greater spindle density over frontal head regions than controls (FAPD: 2.80/min ±1.39/min, control: 1.86/min ±1.35/min, p = 0.040). This study demonstrated that adolescents with FAPD have greater sleep spindle density, higher arousal indices, and lower proportions of slow wave sleep when compared to their peers. This may reflect an underlying difference in physiology which predisposes one to FAPD, or alternatively, may be secondary to pain symptoms themselves. Further investigation is warranted. This research is supported by the Cincinnati Children’s Research Foundation.