Real ear or probe-microphone measurements are a method audiologists use to verify the amount of amplification hearing instruments provide at the patient’s eardrum. This method takes into account the device, hearing loss, and ear canal acoustics to objectively fit hearing instruments to a patient’s ear. Verification is considered best-practice for hearing aid fitting by both of the audiology guiding organizations, the American Academy of Audiology (AAA) and the American Speech-Language-Hearing Association.
The use of these measures is the primary objective path to measure correct hearing aid output in a patient’s ear. Despite the continued advancement in hearing technology, the need to determine what is actually occurring in the ears of our patients while they are wearing hearing instruments remains. Unless we conduct objective measurements, audiologists cannot be certain the hearing instrument is performing the way it is intended to based on the patient’s needs. In order to conduct these objective measures, a patient must first have a thorough, accurate audiometric evaluation. The evaluation is a crucial component in setting up the most appropriate prescription for the patient.
Once appropriate devices are selected for the patient, a real ear measurement device (Verifit, Auricle, etc.) is set up with the patient’s hearing loss and prescriptive formula. Probe microphones are placed into the patient’s ear with the hearing device in place. Several measurements are taken with various speech inputs and adjustments to the hearing device programming are made accordingly. The speech used to take the measurements is important as it contains sounds used in the English language at their appropriate percentages. Depending on the make and model of the measuring device, other languages, including tonal languages, may be taken into account when fitting hearing instruments. An important measurement to consider is the maximum power output (MPO). Again, this measure takes into account the patient’s ear canal acoustics to ensure the MPO does not exceed estimated uncomfortable levels based on the patient’s hearing loss and the devices do not amplify sounds to be “too loud.” The previously mentioned procedures, when conducted appropriately, will provide useful and necessary information throughout the amplification process especially at the time of the hearing instrument fitting. These measures are the most efficient option when comparing different devices objectively as well.
www.audiologyonline.com “Real Ear Measurement: Basic Terminology and Procedures”
https://www.audiologyonline.com “Why isn’t real ear being performed?”