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Speech discrimination with FM Radio Aid
Systems and Cochlear Implant users Results over
distance Flynn SL, Wood EJ and Eyles JA Institute
of Sound and Vibration Research, University of
Southampton UK

Aim To investigate speech discrimination ability
and sound quality over distance with the use of
FM radio aids with cochlear implants.

• Results 1
• The mean score at which subjects identified 71
  toys correctly was-
• 1m without FM aid 54.8dB sd 5.2dB
• 1m with FM aid 41.0dB sd 8.9 dB
• 3m with FM aid 41.3dB sd 10.7dB
• gt10m with FM aid 45.0dB sd 11.3dB
• T-test Results 1m with and without FM aid t-4.4
  plt0.001
• 1m and 3m with FM aid
  t-0.16 NS
• 1m and 10m with FM aid
  t-1.69 NS
• 3m and 10m with FM aid
  t-2.18 plt 0.05
• Correlation BKB and Toy Test r-0.76 plt0.05

Speech levels at 1m

• Method
• The McCormick Automated Toy Test (ATT) was used
  to evaluate speech discrimination over distance.
  The Toy Test uses an adaptive technique to obtain
  a result at which the subject scores 71 correct.
  The maximum level that speech can be delivered is
  70 dB(A).
• Subjects
• 2 children and 8 adults aged between 8 and 76
  years
• 5 male, 5 female
• 5 Nucleus CI22 users with Spectra processors
• 5 Nucleus CI24M users 4 with Esprit processors
  and 1 with a Sprint processor
• All subjects had used their cochlear implants for
  more than 1 year
• The 2 children and 1 adult had used their radio
  aids for at least 1 year
• The latest BKB sentence scores obtained in
  clinic for the adults were between 57-92 key
  words correct in quiet
• The latest Toy Test scores obtained in the clinic
  for the children were both 57dB(A)

Toy test 71 correct score dB(A)
subject

• Results 2
• Sound quality results were obtained from 9 of the
  10 subjects. The youngest of the children (aged 8
  years) was unable to understand the sound quality
  questions. Sound quality scores are reported as a
  percentage where 100 indicates very clear and
  sharp sound with no muffling of the signal,
  hissing, buzzing or echos at all and 0 would
  indicate unclear sound, very muffled sound and
  loud hissing buzzing and echos. Sound quality
  assessments were as follows
• 1m without FM aid 92
• 1m with FM aid 87
• 3m with FM aid 88
• gt10m with FM aid 80

Speech discrimination using FM radio aids and
implants at different distances
Toy Test 71 correct score dB(A)

• Experimental Design
• Each subject used one of 5 radio aids (Connevans
  220, Senheisser, Phonic Ear, Microvox, Solaris)
  and acted as their own control. Each radio aid
  was thus used by 2 subjects.. 4 conditions were
  used in a balanced order.
• ATT with cochlear implant only at 1m
• ATT with FM radio aid and implant at 1m
• ATT with FM radio aid and implant at 3m
• ATT with FM radio aid and implant at gt10m
• After each test condition subjects were asked to
  rate clarity and sharpness of the sound as very
  clear/sharp, okay or not clear/sharp (2
  questions). They were also asked to assess if
  sound was muffled or whether there were any
  hissing, buzzing or echo like sensations choosing
  between the answers none at all, slight and loud
  (4 questions).

subject

• Discussion and Conclusions
• 9 of the 10 subjects were able to discriminate
  speech better with the radio aid at 1m, 3m and
  10m than with out the radio aid at 1m from the
  speaker.
• The ATT scores for this group of subjects were
  the same as for children of a previous study
  (55.4dB(A) sd 6.2dB, Wood, Flynn and Eyles,
  2000).
• Using the FM radio aid at 1m gave a mean score of
  41dB(A) compared with 47.9dB(A) in the previous
  study suggesting that the older more experienced
  listeners in this study were better able to
  discriminate words.
• Sound quality was good over all distances with
  all FM radio aids.
• The slight reduction in ATT scores and sound
  quality at 10m could have been influenced by not
  using the special FM transmitter cable with the
  Connevans and Phonic Ear radio aids with the
  Esprit processor (not recommended with these
  radio aids).
• Cochlear implant users can listen at a
  comfortable level with good sound quality at
  least up to 10m with any of the 5 radio aids
  used.

ATT
References McCormick B (1977) The Toy
Discrimination Test An aid for screening the
hearing of children above the mental age of 2
years. Public Health London 91, 67-69 Wood EJ,
Flynn SL and Eyles JA (2000) The benefit of using
an FM radio aid system with cochlear implant
users. Poster presented at the 6th international
cochlear implant conference CI 2000, Miami
FM transmitter
subject at 1m with and without FM receiver
subject at 3m with FM receiver
subject at gt10m with FM receiver