describe the sound attenuation reflex
when there are sustained loud sounds, the sound attenuation reflex helps to protect the inner ear from damage
- it limits the movement of the ossicular chain
- activation of the tensor tympani muscle (attached to the malleus; CN V) limits the movement of the tympanic membrane
- activation of the stapedius muscle (attached to the stapedius; CN VII) limits the movement of the stapedius
describe the elements of the auditory pathways
does a central lesion in the auditory cortex cause hearing loss?
does a peripheral lesion cause hearing loss?
lesions in which structure produce unilateral hearing loss vs. no hearing loss?
- unilateral hearing loss
- ear
- CN VIII
- cochlear nuclei
- no hearing loss
- damage to auditory cortex
describe the tonotopic organization of the primary auditory cortex
describe the location of the primary auditory cortex and the associated Brodmann’s areas
- primary auditory cortex aka A1 is located on the transverse temporal gyrus aka Heschl’s gyrus aka BA 41 and 42
describe what presbyacusis/presbycusis is
- age-related hearing loss
- progressive bilateral and symmetrical sensorineural hearing loss associated with aging, with higher frequencies being affected most
describe Rinne’s test
- normal (Rinne positive): AC > BC
- conductive loss (Rinne negative): BC > AC
during Weber’s test in patients with conductive hearing loss in one ear, the sound lateralizes to the _____ side of the damaged ear
during Weber’s test in patients with conductive hearing loss in one ear, the sound lateralizes to the ipsilateral side of the damaged ear
during Weber’s test in patients with sensorineural hearing loss in one ear, the sound lateralizes to the _____ side of the damaged ear
in patients with sensorineural hearing loss in one ear, the sound lateralizes to the contralateral side of the damaged ear (towards the unaffected ear)
if Rinne’s test shows both ears AC > BC, explain:
Weber w/o lateralization
Weber lateralizes left
Weber lateralized right
if Rinne’s test shows left ear BC > AC, explain:
Weber lateralizes left
Weber lateralized right
if Rinne’s test shows right ear BC > AC, explain:
Weber lateralizes left
Weber lateralized right
if Rinne’s test shows both ears BC > AC, explain:
Weber w/o lateralization
Weber lateralizes left
Weber lateralized right
