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SN Hearing Loss
S&H A&P PowerPoint 7
Term | Definition |
---|---|
Sensorineural Hearing Loss can be due to (name 5) | Genetic Disorders, Ototoxic Drugs (antibiotics), Endolymphatic Hydrops, Presbycusis, and Noise |
Retrocochlear Hearing Loss | Hearing loss past the cochlea |
Sensorineural Hearing Loss | Hearing loss in sensory cells of Organ of Corti or in the neurons of the Auditory Nerve |
Presbycusis | as you get older you lose hair cells, and thus lose sensitivity to noise |
Endolymphatic Hydrops | when pressure inside the ear is too high, affects balance and hearing |
Temporary Threshold Shift | if exposed to loud sound for a short time (e.g. concert) |
Permanent Threshold Shift | if exposed to loud sound for a long time, leads to irreversible hearing loss |
What are the parameters for noise-induced hearing loss? | The way the sound is presented (pulses, continuous), level of sound (db SPL), and duration |
The first thing effected when exposed to loud sounds | Stereocilia disarray, loss, and fusion--can't be properly deflected against the TM |
The second thing effected when exposed to loud sounds | Outer Hair Cells--when these die, they are replaced by supporting cells (no amplification and vibrations are smaller) |
OHC loss effects | loudness and sharp tuning of the organ of Corti. 40 dB decrease in sensitivity--brain can't tell where the maximum displacement is and hears sounds at different frequencies |
The third thing effected when exposed to loud sounds | Inner Hair Cells--at this point outer and inner HCs are gone, the TM has collapsed, RM has collapsed, and the organ of Corti is destroyed. There is no transduction. |
Without IHCs... | the auditory nerve can no longer function (no action potential fired) |
How does a cochlear implant work? | Electrodes are inserted into your cochlea all along the scala media and will stimiluate different areas based on tonotopy. Will stimulate auditory nerve with electrical discharge rather than glutamate. |
Pitch Shift | May hear sound at higher frequencies when there is IHC loss at certain points along the basilar membrane. |