The Effect of Jaw Position on Measures of Tongue Strength and Endurance

Abstract

Assessment of tongue strength and endurance is common in research and clinical contexts. It is unclear whether the results reveal discrete function by the tongue or combined abilities of the tongue and jaw. One way to isolate the movement of the tongue is to constrain the jaw kinematically by using a bite block. In this study, 10 neurologically normal young adults performed tongue strength and endurance tasks without a bite block ("jaw-free") and with bite blocks of various heights (2, 5, 10, and 15 mm for strength; 5 mm for endurance). Data signals included tongue pressure exerted on an air-filled bulb, surface electromyography (SEMG) from the superior tongue blade, and SEMG from 1 masseter. On average, tongue strength (pressure in kPa) was greatest with no bite block and generally decreased as bite blocks increased in height. Pairwise analyses revealed statistically significant differences for all but 3 comparisons (jaw-free to 2 mm, 2 to 5 mm, and 5 to 10 mm). After removing outlying data from 1 participant, tongue endurance at 50% of tongue strength was significantly greater without a bite block than with one. SEMG data did not differ significantly for the strength task across bite block conditions, but inspection of the individual data revealed a tendency for masseter activity to be lower when the jaw was unconstrained. These results suggest that maximal tongue strength and endurance are best assessed with an unconstrained mandible or with a very small bite block. Keywords tongue function; maximum performance tasks; bite block; assessment; surface electromyography The assessment of oromotor abilities is a common component of most motor speech examinations, especially when cranial nerves or their central innervations are implicated. Clinical assessments typically include measures of strength, endurance, range of motion, and coordination of individual articulators. To assess tongue strength, clinicians commonly hold a tongue depressor beyond the lips and the patient pushes the tongue against the depressor. Strength is rated perceptually, often with a 3-5-point equal-appearing interval scale or with binary judgments of "normal" or "weak." Such measures can provide rough diagnostic information for speech-language pathologists, neurologists, and other movement-disorders specialists. Performance on carefully selected tasks can help isolate cranial nerve dysfunction, as well as implicate side and site of neurologic lesion (Duffy, 1995). Clinicians also have become increasingly interested in oral-motor strength exercises for therapeutic ©American Speech-Language-Hearing Association

Análise da pressão da língua em indivíduos adultos jovens brasileiros

“…This fact can be justified, because, in these tasks, the participants had to press the bulb as much as possible; from the three measurements taken, the highest value was considered (13,14,(20)(21)(22)(23)(24)(25)(26)(27)(28)(29) . Therefore, even though the values in the elevation task did not differ between the genders, the factor more muscle mass in the tongue, besides height and weight (11,12) , among male participants may have contributed for the similar values found in these tasks.…”

Perceptions of effort during handgrip and tongue elevation in Parkinson's disease

“…The incisors rested lightly on the attached tubing, serving to stabilize the jaw in a position found to be optimal for this measure [29]. For the hand, the IOPI hand-bulb was placed in the palm with the fingers wrapped around it in a fist configuration.…”

Caracterização da força da língua por meio de medidas objetivas

“…Previous studies also provided an acoustic signal 14,18 . Regarding the effect of the mandibular position, Solomon and Munson 16 observed in their study that tongue strength decreased as a result of an increase in the height of the oral protectors. Therefore, we believe that an instrument designed to provide reliable data must be capable of controlling the degree of mouth opening and, most of all, of reproducing it.…”

“…Moreover, other factors can affect the assessment of lingual strength, thus possibly invalidating the results, such as the instructions given to the patient, external motivation, number of tests, feedback, or positive reinforcement and the relationship between the position of the tongue and that of the mandible 16,17 . In the present study, the instructions for performing the assessments were accompanied by a demonstration of how to operate the equipment and by a visual feedback of the test, in a situation called training.…”