Habitual lip and tongue posture in infants with Trisomy 21: characterization and associated factors

Purpose  To characterize the habitual lip and tongue posture in infants with trisomy 21 and to verify its association with age, sex, and clinical characteristics.

Methods  This is an observational, cross-sectional, analytical study with a sample of 61 infants with trisomy 21, with a mean age of 7.4 ± 6.2 months. The habitual lip and tongue posture was obtained through the analysis of videos of the infants' faces. Data regarding age, sex, and clinical conditions were collected from the participants' medical records. The study response variables were the habitual tongue and lip postures predominantly adopted by the infants. Explanatory variables included age, sex, prematurity, birth weight, heart disease, hypothyroidism, lung disease, breastfeeding, and use of bottles and pacifiers. Data were analyzed using descriptive statistics and Pearson's chi-square test for association between variables, with a 5% significance level. The study used 20% of the videos to verify the kappa coefficient and obtain intrarater and interrater agreement, classified as excellent and substantial, respectively.

Results  The longest postures were parted lips (48.2%) and tongue inside the oral cavity (32.4%). Lip posture was associated with age at the time of assessment and birth weight, and tongue posture was associated with breastfeeding.

Conclusion  Younger chronological age at the time of assessment and higher birth weight were associated with better lip posture, while breastfeeding was associated with better tongue posture.

Keywords:
Down Syndrome; Muscle Hypotonia; Chromosomes, Human, Pair 21; Tongue; Lip