Audiology - Week 2 - Types of H.L.

WHY relates to SALT
1. OBVS IMPACTS SPEECH DEVELOPMENT
2. Critical period first 3 years - if you don’t pick up speech coz of hearing impairment you get significantly behind in lang. dev.
3. Speech discrimination = functional outcome measure of successful amplification
4. SLT's can be first to pick up a hearing problem, e.g. if a child is not producing any sounds of a certain freq.
  1. Big referral source for audiology & vice verca
5. Children who are aided need big SALT input
6. OTHER INFO SLIDES £$ ONWARDS NOT NOTED HERE
PITCH
1. VOLUME
Consonant and sibilant sounds higher in pitch and not so loudowel sounds louder and lower in pitch
1. Consonant and sibilant sounds higher in pitch and not so loud
2. DEGREES OF HEARING LOSS (Not pitch specific)
TYPES
1. CONDUCTIVE
  1. External Ear
  2. Middle Ear
  3. Reduces sound conduction through to the inner ear
  4. CERUMEN / WAX
  5. Foreign body
  6. Inflaammatory swelling / debris (otitis externa)
  7. Acquired/congenital aural atresia (absence of canal) / exostoses (narrowing") 'surfer's ear'
  8. CHRONIC / BRIEF
  9. AIDED / MANAGED
  10. OTITIS MEDIA - Acute (Infectious) or Chronic (Non-infectious)
    1. Can be drained (although not cured) by grommits
      1. Children have small flat tube, more prone to block if inflamed – more adult like after 6 years)
        More than 7 in 10 children have at least one episode of glue ear before they are four years old.
        Only the 5-8% severe/persistent minority are cases for treatment
    2. Fluid builds up in middle ear and eustacian tube, prevents the ear drum vibrating properly
      1. Eustachian tube is the 'vent' to help maintain same pressure as other side of TM. Air in middle ear passes into nearby cells over time. If it is not replaced by air coming up the tube a vacuum will form, sucking the TM inwards and fluid out from the cells giving glue like consistency
        Most important question: How long have they had it? Fluctuating?
    3. May need temporary hearing aids
  11. Otosclerosis (fusion of the bones) e.g. after pregnancy / genetic
  12. Perforation of T.M. (trauma, infection / operation)
  13. Ossicular discontinuity (trauma / birth defect)
  14. People w conductive HL will still have good bone conduction
    1. Note raised AC thresholds
      1. Then note the BC thresholds WNL, as skipping middle ear...
2. SENSORINEURAL
  1. Congenital~1.5/1000
    1. Maternal infection - particularly CMV, also rubella, HSV
      1. CMV - usually progressive H.L.
    2. Birth complications - premature, asphyxia etc...
    3. Genetic about 50% of HL in children, but most (90%) born to hearing parents
  2. Acquired
    1. e.g. of Presbycusis (getting old)
      1. Inner hair cells become less sensitive
    2. Noise damage - hair cells can be sheared off
      1. Typically shows notch / raised thresholds on audiogram at 3-4kHz
      2. Can be more genetically predisposed to this
      3. Losses up to 50dB will be due to outer hair cell losses.
      4. Hearing losses above 50dB will be due to inner hair cell losses.
    3. Infection - e.g. Meningitis, mumps / measles
      1. Meningitis, cochlea can become ossified (turn to bone) so tend to put a cochlea implant in sooner rather than later
    4. Ototoxic drugs
      1. e.g. Antimalarials 4. Chemotherapy
      2. Also general toxins e.g. viruses, bacteria, environmental, alcohol
    5. Trauma to the ear
      1. Fracture of the temporal bone lead to HL in 70-80% cases
  3. Outer hair cells typicaly the ones to go - provide descrimination
    1. Inner hair cells are the big workers - send signal off to the brain, less likely to falter
  4. Inner Ear or hearing nerve
  5. Usually permanent in nature
  6. Bone Conduction thresholds and Air Conduction are the same - there is no air bone gap
  7. This loss is where the low powered/high freq sibilants and consonants lie and these are the most important components of speech
    1. "Everyone mumbles nowerdays."
  8. FACTORS AFFECTING SPEECH: Severity, frequency and relevant speech sounds, cause (temp/permanent), progressive, aided, aided thresholds and descrimination
    1. Find out if children are wearing their hearing aids
3. TEMPORARY / PERMANENT
MIXED H.L.
'NON ORGANIC' / Faking it
1. Person displays a deficit, where no true hearing loss exists
2. Typified by lack of co-operation / difficulty concentrating on listening tasks
3. Scale anything from phsycosematic - attention seeking
4. Variable, unreliable results
AUDITORY NEUROPATHY
1. Outer hair cell function of inner ear preserved, damage to inner hair cells, or some part of the pathway that relays signals to the brain
2. Damage to inner hair cells
3. Connection between inner hair cell and nerve
4. Damage to auditory nerve
5. Functional deficit varies greatly
6. Lots of SLT
CENTRAL AUDITORY PROCESSING DISORDER
1. Hearing is normal but child has difficulty differentiating, locating and recognising sounds
2. Really tricky to diagnose - may be highlighted by SALT
3. Struggle with hearing, particularly in background noise
4. Difficulty following oral instructions
5. Diff understanding rapid / degraded speech
6. Is it possible this could relate to SLI?
AUDIOGRAM CONFIGURATIONS:
1. Presbycusis
2. Conductive - e.g. glue ear / Meniere’s
3. Congenital - long term 'cookie bite' (may be hard to aid)
4. All freq (should aid well)
5. Noise exposure - dip at 3-4kHz

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Audiology - Week 2 - Types of H.L.

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	Created by Heather Snaith about 8 years ago