Definition: Air-conduction thresholds are the lowest levels at which an individual can hear pure tones presented through headphones or insert earphones. They are measured in decibels (dB HL), with 0 dB HL being the average hearing threshold for a young, healthy adult.
How to calculate air conduction thresholds?
Air conduction thresholds are calculated by presenting a series of pure tones to the ear at different frequencies and intensities. The lowest intensity at which the individual can hear the tone 50% of the time is their air conduction threshold for that frequency.
What is the normal threshold of hearing?
The normal threshold of hearing for young, healthy adults is 0-20 dB HL at frequencies between 250 Hz and 8000 Hz. As people age, their hearing thresholds typically decline, especially at higher frequencies.
What is air conduction on an audiogram?
On an audiogram, air conduction thresholds are plotted as a line that starts at 0 dB HL at 250 Hz and slopes down as the frequency increases. A hearing loss is indicated by a downward sloping audiogram, with the amount of hearing loss being represented by the number of decibels below 0 dB HL.
What is the meaning of air conduction?
Air conduction refers to the way sound travels through the air and into the ear. When sound waves enter the ear canal, they cause the eardrum to vibrate. These vibrations are then transmitted to the middle ear bones, which amplify the sound and transmit it to the inner ear. The inner ear then converts the sound waves into electrical signals that are sent to the brain for processing.
Air-conduction thresholds are an important part of a hearing test. They can be used to diagnose hearing loss and to determine the severity of the hearing loss. Air-conduction thresholds can also be used to monitor hearing loss over time and to track the effectiveness of hearing treatment.