The auditory mechanism is an astoundingly complex and brilliant design. It is truly amazing how sound waves or vibrations in the air, initiate a chain reaction that starts with vibrations to the eardrum and concludes with a neural signal to the cortex. Our physiological reaction, this delicate chain of vibration, pulsation, displacement, conduction, that occurs in response to sound is what allows us to communicate, participate and enjoy music, and the sounds of the world that surrounds us. This design is so fascinating, and so intricate that a slight interruption along this pathway, either occurring at the peripheral or central level, can result in tremendous difficulty with hearing, understanding, or both.
Hearing and understanding are not always codependent. One must be able to hear to capture a spoken message, but hearing alone does not necessitate that the message was understood. The ability to understand an auditory signal ultimately depends on the brain’s capacity to receive and interpret a complete and synchronously fired neural message.
For many older adults who suffer from sensorineural hearing loss, damage to the peripheral auditory system passes incomplete messages to the brain. More than 50% of adults over age 65 have some degree of presbycusis or hearing loss in the higher frequencies. These adults often have difficulty hearing certain higher pitch sounds such as a bird chirpings , certain phones ringing and particular letters of the English alphabet. Because our alphabet is comprised of a combination of vowels, which are lower in frequency, and consonants which are higher in frequency, an individual with high frequency hearing loss, might remark that they can hear, (because they can indeed hear ) but they didn’t understand because they didn’t quite receive all of the information due to the brain’s inability to receive a complete message. In English, consonants envelop vowels to give meaning to speech and hearing only vowels and limited consonant sounds offer opportunities for misunderstanding. “Fifty” and “sixty” sound somewhat alike for someone with presbycusis, especially in noise.
Hearing aids offer tremendous help for most individuals with hearing loss by bringing the inaudible sounds into the range of audibility and offering the brain complete messages. Yet, there are individuals who have difficulty understanding, despite being able to hear. For some, damage to the auditory nerve results in its inability to fire synchronously, delivering an unclear signal to the brain. Some listeners with auditory nerve damage may have normal hearing (when it comes to detecting tones) but cannot interpret speech because the signal sounds distorted or unclear. For many who suffer from a lack of clarity, assistive listening devices in conjunction with aural rehabilitation often result in tremendous improvements in listening.
If you or a loved one has difficulty hearing OR understanding , a hearing evaluation is a first step. There is help for most hearing loss. No one should suffer in silence. Schedule an appointment at an audiologist today.