Pure Tone Audiometry
Pure Tone Audiometry is used to evaluate your ability to hear sounds with different features, namely volume (or amplitude) and pitch (or frequency), through both air conduction (headphones or inserts) and bone conduction (through a bone vibrator on your head). Various sounds are presented at different frequencies and decibel levels. The evaluator assesses your hearing by finding the quietest sound you can hear at the different frequencies. You will be asked to raise your hand or your finger when you hear the sound. The sounds will get softer and softer. During bone conduction testing, the vibration goes to the inner ear or cochlea and skips the outer and middle ear. When you can hear better through bone conduction than air conduction, a mixed or conductive loss is present. When air conduction and bone conduction indicate an equal hearing loss, a sensory neural hearing loss is present.
A second type of audiological evaluation is Speech Audiometry. Speech Reception Thresholds represent the softest level of speech understanding. This is completed using two-part words called Spondee words. A Speech Discrimination Score is then obtained using phonetically balanced words to determine how well you understand what you hear when it is loud enough to hear comfortably. Scores can range from 0% to 100%. A score of 80% or higher indicates good speech discrimination, and a score of 40% or lower indicates poor speech discrimination. A higher score denotes better prognosis for amplification, while a lower score indicates some issues with clarity. Some people have trouble understanding what people say at a quiet level, even though they might be able to hear pure tones in that range. By adding speech to the Pure Tone Audiometry test, the Speech Audiometry test is able to assess your practical level of hearing in a crucial context: conversation.
Tympanometry provides useful information about the mobility of the middle ear system, the presence of fluid in the middle ear space and the volume in the ear canal. A probe is placed in the ear canal and the tympanometer measures the flow of sound energy into the middle ear under conditions of changing air pressure. A graphic representation shows the relationship between the air pressure in the ear canal and the movement of the eardrum and tiny bones of the middle ear space.
After you have had your audiological evaluation, your hearing specialist will compile the results on a graph called an audiogram. The “o’s” represent the right ear and the “x’s” represent the left ear.