Jumping on the Wideband Wagon


With the advent of cell phones and high speed internet, terms like "broadband" and "wideband" have become ubiquitous in our society. The practical applications afforded by these technologies touch nearly every aspect of modern life, so it's hardly surprising that they've recently permeated the practice of audiology with two exciting wideband developments: a .4cc wideband coupler and Wideband Tympanometry (WBT).

Until now, resonance issues associated with the measurement of high frequency stimuli in the HA-1 and HA-2 couplers have precluded widening the frequency range, but the .4cc coupler by Etymonic Design/Audioscan has allowed for a much wider measurement bandwidth. The Audioscan .4cc coupler has made it possible to complete WRECD (Wideband RECD) and measure hearing aid responses in the test box up to 16kHz.  

Wideband real ear measurements are also possible. As hearing aid manufacturers continue to expand the frequency response of their products to 12kHz and beyond, accurate wideband measurement is more essential than ever, and the .4cc coupler (available with the Audioscan Verifit 2) guarantees this accuracy.

Wideband immittance measurements have been researched since the 1980s, but it is only with the release of the Wideband Tympanometry Module for the Interacoustics Titan Middle Ear Analyzer that WBT (Wideband Tympanometry) has become readily accessible for use in clinical practice. WBT utilizes 3 components.  A broad band click stimulus (from 226Hz to 8000Hz), pressurization (+300 to -600 daPA) and middle ear absorbance.  When combined, a 3D tympanogram is generated. 

This 3D tympanogram is comprised of 107 tympanograms which when averaged, yield a WBT that is more stable, with greater sensitivity for easier identification of certain middle ear pathologies.  Contrary to popular belief, the optimum frequency for adults is not 226Hz, but rather an averaged tympanogram from 375Hz and 2000Hz.

For children under 6 months, it is not 1000Hz but an averaged tympanogram from 800Hz to 2000Hz.  Clinicians can still view traditional tympanograms (226, 678, 1000), resonant peak tymps, and  absorbance graphs with normative data.  They are all obtained and displayed simultaneously.    

Perhaps most importantly, the technique and test time required for WBT is identical to that of a standard tympanogram, so the clinician can acquire this patently useful information without impacting the daily clinical flow.  Clearly, the benefits of wideband technology are as far-reaching as its name would suggest.

For additional information on how WBT is shaping the future of audiology, visit http://www.interacoustics.com/academy/e-learning.