Orofacial Strength in a Typically Developing Pediatric Population: A Comparison of the Iowa Oral Performance Instrument and Tongueometer.

PURPOSE: Pressure-based assessments of tongue strength are becoming increasingly common in dysphagia management. However, whether different manometric devices produce comparable measurements for the same tasks, particularly in pediatric populations, remains insufficiently clarified. The purposes of this study were to establish age- and sex-specific reference values for tongue, buccal, and lip strength in a pediatric population using the Iowa Oral Performance Instrument (IOPI) and the Tongueometer (TO) and to systematically examine the effects of device, age, and sex on these measurements, as well as the level of agreement between the two devices.

METHOD: A total of 330 typically developing children and adolescents aged 8-18 years were included. For all participants, anterior and posterior tongue strength, buccal strength, and lip (interlabial) strength were measured using both the IOPI and TO. Device, age, and sex effects were examined using mixed factorial analyses of variance. Age- and sex-specific reference ranges for both devices were reported using descriptive statistics. The agreement between devices was assessed using Lin's concordance correlation coefficient (CCC) and Bland-Altman plots, while the relationship between devices was assessed using linear regression analysis.

RESULTS: Across all parameters, the TO consistently produced lower pressure values than the IOPI. Additionally, the correlation between all measurements obtained with both devices was moderate to strong. Lin's CCC values indicated poor agreement for all measurements, and Bland-Altman analyses demonstrated systematic bias between devices. Age had a strong main effect on tongue, lip, and buccal strength measurements obtained from both devices, whereas sex effects were generally limited and observed for buccal and lip strength measured.

CONCLUSIONS: The IOPI and TO systematically produce different pressure values in pediatric populations and should not be used interchangeably. Accordingly, this study provides age- and sex-specific reference values for both devices to support device-specific interpretation of tongue and orofacial strength measurements in children and adolescents. The results also indicate that age is a stronger determinant of tongue and orofacial strength during childhood and adolescence than sex.