Greater improvements in most QoL and symptom severity measurements were observed in children randomized to undergo adenotonsillectomy , including the parent-completed Pediatric Quality of Life inventory ( effect size -LSB- ES -RSB- : @ ) , the @-item Obstructive Sleep Apnea QoL instrument ( ES : -@ ) , the modified Epworth Sleepiness Scale score ( ES : -@ ) , and the Sleep-Related Breathing Scale of the Pediatric Sleep Questionnaire ( ES : -@ ) .