Factors Affecting Speech Perception

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Factors Affecting Speech Perception

• Mark C. Flynn, PhD
• Dept of Speech Language Therapy

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Classification of Hearing Loss
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Factors affecting Speech Perception

• Unknown factors (50-60!)
• Pure tone hearing loss (30-40)
• Slope of the hearing loss (10)
• Aetiology
• Chronological age
• Duration of Deafness
• Age of Onset
• Gender

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Pure-tone Hearing Loss Slope
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Aetiology of deafness

• Aetiology was the most significant determina of
  spiral ganglion cell survival (Nadoil et al.,
  1989).
• But measures of total count do not take into
  account spread of cell survival of functional
  integrity of the cell.
• In addition, different aetiologies may affect
  cochlear mechanics through differences in
  formation, degeneration of dendrites, new bone
  growth, decalcification, disease and/or trauma.

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• Very few studies have found any effect of
  aetiology because
• insufficient numbers of participants
• the vast majority of participants (50-60) have
  unknown aetiology.
• It is difficult to confirm aetiology prior to
  autopsy.

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Chronological age

• Cognitive decline due to ageing and deficits in
  central auditory processing.
• Factors relating to ageing depend on the nature
  of the speech perception task (Gordon-Salant,
  1987).
• Most speech perception tasks are not sensitive to
  age related decline (Flynn, 1998 Rooij Plomp,
  1992).

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Duration of deafness

• May indicate the degree of degeneration of the
  cochlea.
• Duration effects in research studies could be due
  to improvements in amplification over time
  (Flynn, 1998).

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Age of onset

• Pre-linguistic vs post-linguistic

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Gender

• Some reports that females have better speech
  perception than males (Dubno et al., 1997).
• Most likely to be due to differences in the
  underlying pathology.