May 17, 2013
The importance of word testing.
There is a conventional battery of tests, with a few variations, that give an audiologist diagnostic information about a patient’s ear health and hearing capabilities. Otoscopy allows the examiner to visualize the outer ear, including the external ear canal all the way to the tympanic membrane (eardrum) for malformations, blockages or signs of trauma or disease. Pure tone audiometry assesses the intensity level necessary for a patient to barely detect various frequencies of sound within the spectrum of human hearing. Bone conduction determines the degree to which the outer and middle ear may reduce the amount of sound energy that reaches the inner ear by quantifying any “conductive loss”. Tympanometry, acoustic reflexes and otoacoustic emissions are objective tests of ear function (not hearing per se), and have been described in earlier blog entries. Another vital area of diagnosis is word testing.
There are several reasons audiologists test with words native to the test subject. Verbal communication is obviously the most important reason we have a hearing system, along with safety. Helen Keller famously observed that loss of vision “separates us from objects”, but hearing loss “separates us from people”. This is truer of people who have lost hearing than of people born deaf, but the fact remains that verbal communication is of immeasurable importance for most of us and is the deficit hearing impaired patients complain most bitterly about.
A second reason word testing is necessary is that certain patterns of errors that can ONLY be revealed by careful test administration can act as “red flags” for conditions that require referrals to other specialists, such as otolaryngologists, and additional testing, such as MRI. A competent tester must be familiar with these signs and the proper procedures.
Thirdly, for the many patients who require amplification, a good hearing aid dispenser must understand not only the diagnostic implications of word testing, but also be able use the data to guide selection of the most appropriate instruments. Patterns of word errors are typically consistent with patterns of hearing loss and the frequencies of the sounds patients are missing. Often these are high-frequency consonant sounds, such as /s/, /f/ or /th/. Patients must be given expectations for improvement that are high yet realistic. Word testing is a large component of these expectations.
All hearing testing, especially word testing, must be done in a sound-shielded booth through headphones. An approved word list should be used. Words are not randomly chosen, and the intensity level of the presented words must be appropriate. An old-fashioned “whisper test”, where an examiner stands behind the subject and whispers words to be repeated, is virtually useless.
Always be sure to choose a hearing center that tests thoroughly and explains all results and their implications for you as a patient.