0808 Nighttime Distribution of Periodic Limb Movements of Sleep After Surgical OSA Treatment in Pediatric Population

Abstract Introduction Increased periodic limb movements of sleep (PLMS) can occur in patients with sleep disordered breathing. Changes in PLMS following treatment for obstructive sleep apnea (OSA) are observed, but poorly understood. In adults, PLMS are typically seen in the first portion of the night whereas OSA events occur most frequently during the latter portion. To better understand the link between pediatric PLMS and OSA, we investigated whether nighttime distribution of pediatric PLMS could predict resolution of PLMS following surgical management of OSA. Methods A retrospective study was performed in children and adolescents aged 1-18-year-olds who had pre-operative PSG showing OSA (OAHI ≥1.5/hr) and significant PLMS (PLM index [PLMI] ≥5/hr) before undergoing surgical treatment for OSA and subsequent post-operative PSG. The cohort was divided into 2 groups based on post-operative PSGs; (1) sustained PLMS with PLMI index >5/hr post-operatively and (2) resolved PLMS with PLM index < 5/hr postoperatively. PLMS distribution was qualified by calculating PLMI during each third of the night of pre-operative PSG. The age, PSG parameters and PLMS distribution were compared between patients with sustained PLMS and resolved PLMS. Results Twenty-seven subjects met the criteria for entry into analysis; 14 patients with sustained PLMS and 13 patients with resolved PLMS. Sustained PLMS had higher overall PLMI compared to resolved PLMS (15.13±8.02/hr vs. 9.77±5.88/hr, p=0.03). Sustained PLMS had a higher PLMI during the first third of the night on pre-operative PSG compared to resolved PLMS (15.99±10.37/hr vs. 6.05±8.02/hr, p=0.01). There were no significant differences in PLMS in the middle and last thirds of the night, BMI, age (6.37±4.20 vs. 5.07±4.10 years) at sleep study, AHI, or OAHI (8.11 vs. 6.04). Conclusion Children with PLMS that resolved after surgical treatment for OSA have less frequent PLMS in the early part of the night and a lower overall PLMI compared to children with sustained PLMS. This suggests that PLMS occurring in the first third of the night are independent of sleep disordered breathing and are likely associated with other conditions such as sleep related movement disorders. The distribution of PLMS may help prioritize children with OSA and PLMS who require further evaluation of RLS/PLMD post-operatively. Support (if any)