Background: Measurements of tongue force are important in clinical practice during both the diagnostic process and rehabilitation progress. It has been shown that patients with chronic temporomandibular disorders have less tongue strength than asymptomatic subjects. Currently, there are few devices to measure tongue force on the market, with different limitations. That is why a new device has been developed to overcome them. The objectives of the study were to determine the intra- and inter-rater reliability and the responsiveness of a new low-cost device to evaluate tongue force in an asymptomatic population.
Materials and methods: Two examiners assessed the maximal tongue force in 26 asymptomatic subjects using a developed prototype of an Arduino device. Each examiner performed a total of eight measurements of tongue force in each subject. Each tongue direction was measured twice (elevation, depression, right lateralization, and left lateralization) in order to test the intrarater reliability.
Results: The intrarater reliability using the new device was excellent for the measurements of the tongue force for up (ICC > 0.94), down (ICC > 0.93) and right (ICC > 0.92) movements, and good for the left movement (ICC > 0.82). The SEM and MDC values were below 0.98 and 2.30, respectively, for the intrarater reliability analysis. Regarding the inter-rater reliability, the ICC was excellent for measuring the tongue up movements (ICC = 0.94), and good for all the others (down ICC = 0.83; right ICC = 0.87; and left ICC = 0.81). The SEM and MDC values were below 1.29 and 3.01, respectively, for the inter-rater reliability.
Conclusions: This study showed a good-to-excellent intra- and inter-reliability and good responsiveness in the new device to measure different directions of tongue force in an asymptomatic population. This could be a new, more accessible tool to consider and add to the assessment and treatment of different clinical conditions in which a deficit in tongue force could be found.
Keywords: feedback; muscle strength; neurofeedback; rehabilitation; reproducibility of results tongue.