MLSHAPPL: Hearing

• Hearing


  Ear transforms sound vibration captured from the external environment into nerve impulses
• Air conduction


  • Acoustic signals travels through outer and middle ear and arrives at trochlea
• Bone Conduction


  • Acoustic or mechanical stimulation of the skull
• Conductive Hearing Loss (CHL)


  • Sounds cannot get through outer and middle ear
• Sensorineural Hearing Loss (SNHL)


  • Most common type
  • The inner ear is damaged
  • Inability to hear faint sound and loud sound in severe cases
• Mixed Hearing Loss


  • There may be damage to the outer/middle or inner ear
• Test In identifying hearing loss

  1. Weber Test

  2. Rinne Test
• Weber Test


  Heard in the midline
• Rinne Test


  Heard by using air and bone conduction
• Different Ear Conditions

  • Presbycusis - age related. gradual loss of hearing in both ears
  • Tinnitus - sound does not have an external source, you hear it, others can not
  • Otitis Media - inflammation in the middle ear
  • Otitis Externa - inflammation of external auditory canals
• Rinne Test


  AC > BC - Normal

  BC > AC - Conductive hearing loss

  AC > BC but AC is not 2x the BC - Sensorineural hearing loss