Question
My practice is a 'bare bones' practice. We do not have real ear equipment. Nonetheless, we would like to verify performance of directional microphones for our patients. How can we accomplish this?
Answer
One ''low tech,'' yet effective, approach to verification is to perform a listening check on the hearing instrument. Performing a standard listening check on instruments with directional microphones is the quickest method for verifying the performance of directional microphones.
Couple the hearing instrument to your listening stethoscope. With the instrument turned on and in the directional mode, gently rub your finger or a cleaning brush over each microphone. Both microphones should sound active and the contact with each individual microphone should be amplified. To hear the directional effect, hold the instrument with both microphones in a parallel plane and with the front microphone facing you, produce a steady, state sound (a ''Shhhh'' or an ''Mmmm'' sound can be very effective). Without changing the intensity of the sound you are producing, slowly rotate the instrument 180 degrees so that the rear microphone is now facing you. There should be an audible decrease in gain when the rear microphone is facing you and the front microphone is facing away from you.
Specific notes for TRIANO™ hearing instruments from Siemens: Before performing this check with TRIANO instruments, it is important to understand the function of the automatic feature. When the automatic feature of TRIANO is activated, these instruments will function in an omnidirectional mode until a sufficient acoustic signal prompts them to transition to directional mode. Since a signal of approximately 60 dB SPL or stronger needs to be presented to transition to the directional mode, and the complete transition to directional may take up to 8 seconds, you may want to disable the automatic feature during a listening test. From the TRIANO programming screen in CONNEXX™, simply click the Speech Comfort/Mic tab, and uncheck the box next to ''Automatic.''
Further information regarding verifying directionality with hearing instruments from Siemens can be obtained from the Siemens audiology staff at 800-766-4500.
Author: Eric Branda, MS/CCC-A, Staff Audiologist, Siemens Hearing Instruments
Brief Bio: In his position as Staff Audiologist, Eric assists Hearing Care Professionals with hearing instrument selection, fitting and post-fitting audiology support. Prior to joining Siemens, Eric worked at a busy private practice in Michigan performing diagnostic audiology and dispensing hearing instruments. Eric received his Master's Degree in Audiology from the University of Akron, OH.
For more information please click here.
