Maximum Anterior Tongue Strength and Maximum Lip Strength in Healthy Spanish Adults: A Proposal of Reference Values

Abstract

Adequate tongue and lip strengths are needed for normal speech, chewing, and swallowing development. The aim was to evaluate the influence of sex and age on maximum anterior tongue strength (MTS) and maximum lip strength (MLS) in healthy Spanish adults to establish reference values that can be used in clinical practice. This cross-sectional study comprises 363 subjects (mean age 47.5±20.7 years) distributed by sex (258 women and 105 men) and across three age groups: Young (18-39 years), middle-aged (40-59 years), and older adults (>59 years). MTS and MLS were determined using the Iowa Oral Performance Instrument (IOPI). The mean MTS was 49.63±13.81 kPa, regardless of sex, and decreased with age. The mean MLS was statistically higher for men (28.86±10.88 kPa) than for women (23.37±6.92 kPa, p = 0.001), regardless of age. This study provides the first reference values for the standardized measurement of MTS and MLS in a healthy adult Spanish-speaking population using the IOPI.