Physiology of Hearing

Anatomical Pathway of Sound

The American College of Radiology states that sound enters through the external ear and causes vibration of the tympanic membrane, which is then transmitted through the three ossicles of the middle ear (malleus, incus, and stapes) 1

The American College of Radiology recommends that hair cells serve as auditory receptors, converting the mechanical energy of sound waves into electrical neural impulses 1

The American Academy of Otolaryngology-Head and Neck Surgery states that conductive hearing loss results from abnormalities of the external ear, tympanic membrane, middle ear space, or ossicles 3
The American Academy of Otolaryngology-Head and Neck Surgery states that sensorineural hearing loss results from abnormalities of the cochlea, auditory nerve, or central auditory pathways 3
The American Academy of Otolaryngology-Head and Neck Surgery states that mixed hearing loss is a combination of both conductive and sensorineural components 3

The American Academy of Otolaryngology-Head and Neck Surgery recommends that audiologic testing is the preferred method for hearing assessment 4
The American Academy of Pediatrics states that physiologic measures used to assess hearing include otoacoustic emissions (OAEs) and auditory brainstem response (ABR) 5
The American Academy of Otolaryngology-Head and Neck Surgery states that tuning fork tests (Weber and Rinne) can help differentiate between conductive and sensorineural hearing loss 6, 3

The International Journal of Occupational and Environmental Medicine reports that recent animal studies have shown that moderate noise exposure can trigger irreversible degeneration of auditory nerve fibers without affecting outer hair cells or permanent hearing thresholds 7, 8
The International Journal of Occupational and Environmental Medicine states that this phenomenon, called "hidden hearing loss," may explain why some patients with normal hearing thresholds still experience difficulty understanding speech in noisy environments 8