Comparative analysis of masseter muscle electrical activity by nasal patency in children with rhinitis and asthma: a pilot observational study.

PURPOSE: This pilot cross-sectional study aimed to evaluate differences in electromyographic activity patterns of the masseter muscle according to the nasal patency in children with rhinitis and asthma. METHODS: The study included 43 children aged 5-14 years with rhinitis and/or asthma. Patients underwent peak nasal inspiratory flow (PNIF) measurement to assess nasal patency, and electromyographic evaluation of the right and left masseter muscles during chewing and at rest. Electromyographic activity patterns according to nasal patency were compared using the Mann-Whitney test, and effect sizes were measured using the Glass rank biserial (rb) correlation. A p-value of < 0.05 was considered statistically significant. RESULTS: No significant differences in electromyographic activity of the masseter muscle at rest, during unilateral chewing, or during habitual chewing were found between the groups. However, we found that patients with low nasal patency had a median electric activity of the right masseter muscle during maximum contraction of 60.53 (51.74-72.43), while those with adequate nasal patency had a median of 77.40 (56.71-88.45). Although the difference in myoelectric activity between the groups did not reach statistical significance (p = 0.061) at the adopted significance level of 5%, the size of the difference between groups were considered moderate (rb = 0.338) and a potential association between nasal patency and the muscular function of the masseter muscle could be suggested. CONCLUSION: The study found no differences in the electromyographic activity of the masseter muscle at rest, during unilateral chewing, or during habitual chewing among children with rhinitis and asthma based on nasal patency. Further research with larger sample sizes is needed to validate these findings and gain a better understanding of the impact of nasal patency on the muscular function of the masseter muscle.

Association between nasal patency and orofacial myofunctional changes in patients with asthma and rhinitis.

PURPOSE: To verify the association between orofacial myofunctional changes and nasal patency. METHOD: Observational study of 43 children and adolescents with asthma and/or rhinitis, aged between 5 and 14 years, from May 2017 to September 2019. Patients underwent peak nasal inspiratory flow (PNIF) for nasal patency assessment and orofacial myofunctional assessment. Clinical data were obtained from an interview on the day of the patients' medical evaluation. The relationship between orofacial myofunctional changes and PNIF was analyzed using a logistic regression model. Estimates were reported as odds ratio (OR) and 95% confidence interval (95%CI). We evaluated multicollinearity using the variance inflation factor and analyzed the adjusted fit with the Akaike information criterion and McFadden's R2 metric; p value < 0.05 was considered statistically significant. RESULTS: Inadequate positioning of the mandible (OR = 11.22; 95%CI 1.83-69; p = 0.009) and the presence of tension in the facial muscles during the swallowing of liquid (OR = 4.61; 95%CI 1.31-16.20; p = 0.017) were associated with altered PNIF in children and adolescents with asthma and rhinitis. CONCLUSION: Children and adolescents with asthma and rhinitis along with reduced nasal patency presented orofacial myofunctional changes, such as inadequate positioning of the jaw and the presence of tension in the facial muscles during swallowing of liquid.