The audiogram is a graph of how someone hears. Across the top are the frequencies, or pitches, of sounds, from low sounds to high sounds. Down the side are measures of intensity, or loudness, of sounds, from soft sounds to loud sounds. In the middle of the audiogram there is a part called the “Speech Banana.” Most of the sounds of speech fall into that range of pitches and loudness. Our goal is for the child to be able to hear in or above the Speech Banana with hearing aid(s), Baha, or cochlear implant(s) to have access to the sounds of speech. In the speech banana, you can find the sounds a, u, i, sh, s, m, better known as the Ling Six Sounds. These sounds span the length of the Speech Banana. When someone responds (through a behavioral response or imitation) to a Ling Six Sound Check, we can be reasonably sure that they has access to all of the sounds of speech.
When a someone has an audiological exam, many things may take place. The client may wear insert plugs, earphones, or listen to sounds played over speakers (called a “soundfield”) while sitting in an acoustically treated booth. Tones will be played at various pitches and intensities. The responses may be measured by various means for younger children and babies measurements will also be taken visually including:
- Behavioral Observation Audiometry (BOA): measuring responses based on behavior (eye blinking, eye widening )
- Visual Reinforcement Audiometry (VRA): measuring the responses based on a head turn to a screen or light-up box
- Conditioned Play Audiometry (CPA): measuring the responses based on a conditioned play response (stacking rings, putting a block in a bucket, etc.)
Air Conduction refers to sounds transmitted through the air (soundfield, headphones, inserts). This tests if sounds are audible after going through the outer, middle, and inner ear. Bone Conduction refers to sounds transmitted through a bone oscillator. Those sounds bypass the outer and middle ear and test inner ear (cochlear) functioning alone. People with a conductive hearing loss have difficulty with air conduction testing due to outer or middle ear issues, but they will perform well on bone conduction testing, as they do not have problems with cochlear hearing. People with sensorineural hearing loss will have difficulty hearing tones presented through both media (air and bone conduction). People with mixed hearing loss will have components of both types of hearing loss.