[Code of Federal Regulations] [Title 21, Volume 8] [Revised as of April 1, 2008] From the U.S. Government Printing Office via GPO Access [CITE: 21CFR874.1090] [Page 365] TITLE 21--FOOD AND DRUGS CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) PART 874_EAR, NOSE, AND THROAT DEVICES--Table of Contents Subpart B_Diagnostic Devices Sec. 874.1090 Auditory impedance tester. (a) Identification. An auditory impedance tester is a device that is intended to change the air pressure in the external auditory canal and measure and graph the mobility characteristics of the tympanic membrane to evaluate the functional condition of the middle ear. The device is used to determine abnormalities in the mobility of the tympanic membrane due to stiffness, flaccidity, or the presence of fluid in the middle ear cavity. The device is also used to measure the acoustic reflex threshold from contractions of the stapedial muscle, to monitor healing of tympanic membrane grafts or stapedectomies, or to monitor followup treatment for inflammation of the middle ear. (b) Classification. Class II.