The present findings represent an important step in demonstrating the potential efficacy of PAP intervention in reversing two of the most prominent daytime effects of adolescent OSA: inattention and poor school performance. Impressively, a group of adolescents with even modest levels of PAP adherence (57% on average) displayed stable or improved attention and school performance, whereas a similar group of non-adherent adolescents trended towards declines in academic and school performance. This potential utility of even partial adherence to PAP therapy mirrors adult findings, in which improved sleepiness and quality of life have been observed in groups in which PAP use averages around 50% of each night 
. It remains unknown whether, beyond such group averages, greater individual PAP usage results in greater gains in daytime functioning.
Present findings extend prior work that suggested an improvement in daytime sleepiness after PAP treatment in pediatric populations 
. There are multiple potential mechanisms by which such gains might occur. When titrated properly and used consistently, PAP markedly reduces or eliminates the sleep disruption and gas exchange abnormalities that characterize OSA 
; both have been proposed to be key mechanisms that underlie OSA-related neurobehavioral morbidity, and there is evidence to support both as sufficient but not necessary causes of such morbidity 
. Attempts within the current sample to quantify sleep quantity and quality using objective actigraphy before and after treatment were regrettably unsuccessful because of missing data related to poor adherence with wearing the actigraph units at one or both measurement time points.
Although present results provide important evidence that can be used to support and justify future larger-scale research, findings are considered preliminary. The sample was small, in part due to substantial loss of subjects to follow-up. This has also been observed in the limited other studies in this area 
, suggesting that future work will need to institute a highly comprehensive subject retention protocol or an initial “run-in” period (e.g., demonstration of PAP use at sub-optimal pressure prior to titration) to screen prospective subjects. Our reliance on parent-report of adherence is a further limitation, though if anything the lack of precision associated with such reports would tend to obscure findings, suggesting that current findings may in fact be conservative. Despite concerns that parent-report might overestimate adherence, PAP adherence still tended to be poor in our sample, similar to or slightly worse than that which has been observed among other adolescent samples via objective monitors 
. Assignment to the groups was not random, and though the groups did not significantly differ on demographic variables or baseline functioning, this may have been due to inadequate statistical power for cross-sectional analyses; in a larger sample, baseline characteristics might prove to be significant predictors of adherence and change in attention or scholastic performance. It is also possible that unmeasured factors (e.g., family disorganization) could confound results, or that adolescents who experienced initial clinical improvements became more motivated to maintain or increase PAP usage. An experimental trial, in which children with known OSA are randomized to a PAP versus placebo (“sham-PAP”) condition could help to eliminate confounds, but would still need to deal with issues of adherence in the treatment arm and would further require careful ethics consideration.
Although these limitations suggest a need for study replication and extension in larger-scale studies, present findings may have important clinical and public health implications. Adolescent obesity has reached epidemic prevalence, placing many adolescents at high risk for OSA 
while simultaneously reducing the success and increasing the complication rates associated with airway surgery 
. The scholastic impact of untreated OSA may be of particular concern during adolescence, when school performance more clearly predicts long-term outcomes than at any prior developmental stage 
. Conversely, successful treatments during adolescence may have particularly high long-term yield 
. Findings from this study are consistent with clinical recommendations for PAP treatment in adolescents with OSA 
, and add an empirical foundation for clinicians to use while communicating the importance of PAP therapy adherence to patients and their families.
Because PAP adherence rates are low and adolescents who are non-adherent remain at risk for significant medical and neurobehavioral morbidity, it is imperative that future research identify the key obstacles to PAP adherence among adolescents. Considerable progress has been made in identifying predictors of PAP adherence in adults 
. However, such predictors are likely to be unique in pediatric populations due to developmental factors, including the adolescent transition from parent-directed care to patient-directed care. Based upon the minimal pediatric data available, neither demographic factors nor the mode of PAP delivery (single-level versus bi-level) appear to be major adherence predictors, though some aspects of pre-treatment disease severity may predict adherence 
. In adolescents, correlates of PAP use remain largely unexplored 
. Present results, which suggest that adolescent adherence levels are related to changes in functional outcomes, highlight the need for additional work in this area so that novel therapies that promote PAP adherence can be developed and tested.