Surface Motion of Tympanic Membrane in a Chinchilla Model of Acute Otitis Media

In this study, the TM surface motion was determined using scanning laser Doppler vibrometry (SLDV) in a chinchilla model of AOM. The AOM was established by transbullar injection of nontypeableHaemophilus influenzae. The TM surface vibration was measured in control (uninfected) animals and two AOM groups of animals: 4  days (4D) and 8 days (8D) post inoculation. To quantify the effect of middle ear pressure in those infected ears, the SLDV measurement was first conducted in unopened AOM ears and then in middle ear pressure released ears. Results showed that middle ear infection generally reduced the TM displace ment across the entire surface, but the reduction in the umbo displacement over the time course, from 4 to 8 days post inoculation, was less than the reduction in the displacement at the center of each quadrant. The presence of middle ear fluid shifted the occurrence of traveling-wave-like motion o n the TM surface to lower frequencies. The observation of the spatial variations of TM surface motion from this study will help refine our understanding of the middle ear sound transmission characteristics in relation to AOM.
Source: JARO - Journal of the Association for Research in Otolaryngology - Category: ENT & OMF Source Type: research