Which device is commonly used to test the middle ear function?

The tympanometer is the correct device used to test middle ear function. It measures the mobility of the eardrum and the condition of the middle ear by creating variations in air pressure in the ear canal. This process provides critical information about the ability of the tympanic membrane to move in response to sound waves, which can indicate if there are any issues such as fluid in the middle ear, eustachian tube dysfunction, or other problems affecting middle ear function.

In contrast, an otoscope is primarily used to visualize the ear canal and the eardrum to check for signs of infection or blockage, rather than testing the function of the middle ear itself. A screener typically refers to equipment used for general hearing screenings, which do not specifically evaluate middle ear function. An audiometer is employed for determining the hearing levels of an individual across different frequencies but also does not focus on the middle ear's performance. Therefore, the tympanometer is uniquely suited for assessing middle ear health, making it the appropriate choice among the options provided.