Purpose: Instrumental assessments of tongue strength have provided clinicians with the ability to obtain quantitative measures to document lingual weakness. A technical challenge with a common instrument is that the surface of the of the bulb-shaped sensor is smooth and can be slippery when contacted by the tongue. This study evaluated whether adding a textured layer to the bulb leads to enhanced strength measures in neurologically normal adults. Methods: Maximum-effort maneuvers for anterior and posterior tongue elevation, right and left tongue lateralization, and tongue protrusion were available from 62 healthy adults using the Iowa Oral Performance Instrument (IOPI). The IOPI tongue bulb was either bare or covered with a single layer of gauze. The maximum pressure (Pmax) exerted on the bulb from three trials was used as the outcome variable for each task. Results: In addition to significant main effects for both bulb-cover and task, there was a significant interaction between the use of gauze and the direction of the tongue-strength maneuver. Pmax was significantly greater when a gauze-covered bulb was used for tongue lateralization and protrusion but not for tongue elevation maneuvers. Conclusion: Using a single-layer of gauze on the smooth tongue-bulb helped reduce slippage of the tongue and resulted in greater Pmax values when evaluating tongue strength in the lateral and protrusive directions, but not for tongue elevation. Efforts to develop a more permanent solution to texturizing the bulb’s surface are needed.


tongue strength, objective orofacial assessment, reliability