Hearing Impairment

• hearing loss and hearing function measured in 


  units of dBHL
• air conduction 


  sounds detected through the usual auditory route
• bone conduction 


  sound conducted directly into the cochlea through the bone in the skull
• conductive hearing loss 


  physical damage or obstruction to the outer or middle ear
• neural hearing loss 


  permanent damage to hair cells or nerves in the inner ear
• conductive hearing loss example 


  normal bone conduction and impaired air conduction
• causes of conductive hearing loss 


  ear infection, earwax, hole in eardrum, fluid in middle ear
• neural hearing loss example


  impaired bone conduction, and impaired air conduction
• causes of neural hearing loss 


  damage to hair cells, damage to auditory nerve, neurodegeneration (noise exposure or age)
• when is a hearing aid needed? 


  if hearing less than 55dBHL