## 3 Results  
A total of 122 patients eligible for the study were evaluated. This initial group, at T0 (pre-RPE), underwent AAR and the SRDB or PSQ-SRDB questionnaire. At T0, the AAR was clinically significant in 42 subjects (study group), 27 females (64%) and 15 males (36%), with a mean age of 7.7 years (range 5-12 years; median 8 years) (Table 1). In this case, the AAR was repeated at T1 (post-RPE) in order to assess the extent of improvement on respiratory function and sleep quality at the end of orthopedic treatment. The population was homogeneous with respect to the sex variable (\(p\) = 0.217), while it was not homogeneous for the age variable (\(p\) = 0.000). Among them, 37 were found to be oral respiratory from an obstructive cause while 5 manifested non-obstructive oral breathing. Compared with 37 oral breathing patients from an obstructive cause, 26 had adenoid hypertrophy (70%), 19 had tonsillar hypertrophy (51%); 21 showed hypertrophic turbinates (57%); and 19 were affected by septal deviation (51%). In addition, 15 patients were affected by snoring (41%) and 4 manifested apneas (11%) (Table 2). In contrast, of the five oral respiratory patients from a non-obstructive cause, four revealed the concomitant presence of snoring and apneas (80%) (Table 3). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sex** & **N Observed** & **N Expected** & **Residual** & **Mean Age** & **Median Age** \\ \hline F & 25 & 21.0 & 4.0 & & \\ M & 17 & 2.0 & \(-\)4.0 & & \\ Total & 42 & & & 7.71 & 8 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Demographic characteristics of the study group categorized by sex and age variables. Figure 2: Flow chart diagram. Relative to the oral obstructive respirators, it was investigated whether the patients had previously undergone or were on the waiting list for adenotonsillectomy or adenoidectomy surgery. It was found that five of them had had prior surgery (four underwent adenotonsillectomy and one underwent adenotectomy) while five subjects were on the waiting list for adenotonsillectomy. Nasal resistance values (pre- and post-treatment) assessed with AAR: Figure 3a,b shows, using box plots, the distributions of the variables representing the change between T0 and T1 of the resistances divided by left and right nostril. In them, the dashed blue lines are placed at the mean value of these variables, indicative of the general effect of treatment for both nostrils on the subjects in the sample under study. From the analysis of these, it can be deduced that, on average, the therapy led to a general reduction in the values of resistance to airflow opposed by both nostrils: for the left cavity, a negative average pre-/post-treatment change of 24.63% is observed, while for the right nostril, an average decrease of 26.65% is observed between T0 and T1. Using the Student's \(t\)-test on the variable variation, with the null hypothesis that the mean variance is zero, it was analyzed whether the reduction in nasal resistance to airflow opposed by the two nostrils was statistically significant. The \(t\)-test, performed for each nostril, shows that in both nasal sides the null hypothesis was rejected (\(p=0\)). From this, we infer that RPE treatment had a significant impact on nasal airflow resistance in both nostril sides. Specifically, the confidence intervals, calculated at 95% in the two nostrils, attest that in the sample, representative of the population examined, the variable variation takes on negative values between \(-11\%\) and \(-37\%\) (confidence interval 95%) (Tables 4 and 5). As can be seen, in both tests the \(p\)-value has a value of 0, which suggests that the result of the \(t\)-test is very strong; thus, the variance on average was not zero. Therefore, despite the presence of zero or negative changes in resistance, it is still possible to show that treatment with RPE induces a statistically significant and positive improvement on nasal function, at least in terms of reduction in expressed nasal resistance.