Final answer:
The IOPI is not strictly used in the mouth; it can measure and strengthen tongue strength and can also be applied for hand grip strength exercises in rehabilitation.
Step-by-step explanation:
The statement 'IOPI is strictly used in the mouth' is false. IOPI, which stands for Iowa Oral Performance Instrument, is designed primarily for assessing and exercising the muscles involved in swallowing and speech within the mouth. However, it can also be used to measure and strengthen tongue strength and endurance as well as the strength of other muscles, including those in the hand for grip strength exercises in rehabilitation settings.