NeutronicEar | You and your Hearing Health
From our friends at Wikipedia, we provide the following definition for human hearing and hearing health:
Hearing (or audition; adjectival form: “auditory” or “aural”) is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses. The inability to hear is called deafness.
In humans and other vertebrates, hearing is performed primarily by the auditory system: vibrations are detected by the ear and transduced into nerve impulses that are perceived by the brain (primarily in the temporal lobe). Like touch, audition requires sensitivity to the movement of molecules in the world outside the organism. Both hearing and touch are types of mechanosensation.
The eardrum of an ear simplifies incoming air pressure waves to a single channel of amplitude. In the inner ear, the distribution of vibrations along the length of the basilar membrane is detected by hair cells. The space–time pattern of vibrations in the basilar membrane is converted to a spatial–temporal pattern of firings on the auditory nerve, which transmits information about the sound to the brainstem.
The Human Ear is made up of many parts working together in order for us to fully understand words and various sounds from various distances and locations. Click on picture for for greater detail.
Hearing can be measured by behavioral tests using an audiometer. Electrophysiological tests of hearing can provide accurate measurements of hearing thresholds even in unconscious subjects. Such tests include auditory brainstem evoked potentials (ABR), otoacoustic emissions (OAE) and electrocochleography (EchoG). Technical advances in these tests have allowed hearing screening for infants to become widespread.
The auditory brainstem response (ABR) is an auditory evoked potential extracted from ongoing electrical activity in the brain and recorded via electrodes placed on the scalp. The resulting recording is a series of vertex positive waves of which I through V are evaluated. These waves, labeled with roman numerals in Jewett and Williston convention, occur in the first 10 milliseconds after onset of an auditory stimulus. The ABR is considered an exogenous response because it is dependent upon external factors.