Module 4

1. Module 4 Needs of Hard of Hearing Children in Schools

2. Being deaf or hard of hearing is not a learning disability !

3. Hearing and Academics “It has long been recognized that hearing loss and auditory processing disorders (APD) affect a child's ability to learn language and achieve academically” Source: ASHA Guidelines for Audiology Service Provision in and for Schools http://www.asha.org/policy/GL2002-00005/

4. Complex Problems of Deaf and Hard of Hearing Students • Listening • Speech • Language • Cognition • Academics • Reading and writing (accompanies speech and spoken language problems) • Emotions and social relations

5. History • Before and after newborn hearing screening • Impact of mainstreaming (inclusion)

6. History – Before NHS • You don’t need much hearing loss to have an impact • Very important that language is not delay before the child enters school because that affects his or her ability to listen. • Almost 50% of time at school is spent listening.

7. History – Before NHS • There were more artic errors before early intervention, leading to social and emotional problems. • Before Newborn Hearing Screening, many children were 2 or more years behind academically by the end of elementary school, and many did not finish grade 12.

8. History – Impact of Mainstreaming • 50% of hard of hearing children are in schools with 1-3 other hard of hearing students • 19% are the only hard of hearing student at their school

9. History – Impact of Mainstreaming • Increased demands on auditory system, especially for those with more severe hearing losses. • Child may feel socially isolated because he/she may not know anyone else at their school who is deaf or hard of hearing.

10. Barriers to Education of Hard of Hearing Students • Acoustics • Distance • Signal to Noise Ratio (children need better SNR) • Reverberation • Decreased speech perception ability • Auditory Processing • Otitis media / fluctuating hearing (still very common in 5, 6 and 7 year old children).

11. Sensorineural Hearing Loss

12. Sensorineural Hearing Loss A sensorineural hearing loss has the following effects: • Loss of sensitivity (remedy: amplification) Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

13. Sensorineural Hearing Loss A sensorineural hearing loss has the following effects: • Loss of sensitivity (remedy: amplification) • Loss of dynamic range (remedy: compression) Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

14. Sensorineural Hearing Loss A sensorineural hearing loss has the following effects: • Loss of sensitivity (remedy: amplification) • Loss of dynamic range (remedy: compression) Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

15. Sensorineural Hearing Loss A sensorineural hearing loss has the following effects: • Loss of sensitivity (remedy: amplification) • Loss of dynamic range (remedy: compression) • Loss of temporal resolution (remedy: ??) • Loss of spectral (frequency) resolution (remedy: ??) Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

16. Loss of Spectral and Temporal Resolution • Not measured routinely in clinic Source: Phonak Introduction to FM (http://www.phonakpro.com)

17. Loss of Spectral and Temporal Resolution • Not measured routinely in clinic • Especially affects hearing in noise Source: Phonak Introduction to FM (http://www.phonakpro.com)

18. Loss of Spectral and Temporal Resolution • Not measured routinely in clinic • Especially affects hearing in noise • Subtle speech information gets lost Source: Phonak Introduction to FM (http://www.phonakpro.com)

19. Loss of Spectral and Temporal Resolution • Not measured routinely in clinic • Especially affects hearing in noise • Subtle speech information gets lost • No current hearing aid technology can solve this problem Source: Phonak Introduction to FM (http://www.phonakpro.com)

20. Sensorineural Hearing Loss A sensorineural hearing loss has the following effects: • Loss of sensitivity (remedy: amplification) • Loss of dynamic range (remedy: compression) • Loss of temporal resolution (remedy: ??) • Loss of frequency resolution (remedy: ??) • Loss of spatial location (remedy: ??) • No release from masking (remedy: ??) In fact, hearing aids sometimes has an adverse effect on some of these skills Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

21. Sensorineural Hearing Loss • Even the best technology (hearing aids, BAHA’s, cochlear implants) cannot restore normal hearing function.

22. Distance, noise and reverberation. Classroom Acoustics

23. Distance, noise and reverberation. Noise is the biggest problem in a typical classroom. Classroom Acoustics

24. Distance, noise and reverberation. Noise is the biggest problem in a typical classroom. Internal and external noise. Classroom Acoustics

25. Distance, noise and reverberation. Noise is the biggest problem in a typical classroom. Internal and external noise. Reverberation is less of a concern in small classrooms. Some absorbent surfaces are recommended. Gymnasiums and hallways have very high reverberation. Classroom Acoustics

26. Distance, noise and reverberation. Noise is the biggest problem in a typical classroom. Internal and external noise. Reverberation is less of a concern in small classrooms. Some absorbent surfaces are recommended. Gymnasiums and hallways have very high reverberation. No more than 35 dBA is recommended for noise levels. Classroom Acoustics

27. Acoustics Together, distance, signal to noise ratio and reverberation are called ACOUSTICS. Turning up the volume on hearing aids may not help. It may actually make it worse.

28. Effects of Noise on Speech Intelligibility Levitt, H. and Webster, J. C. Figure 16.3 of "Chapter 16. Effects of Noise and Reverberation on Speech," Handbook of Acoustical Measurements and Noise Control, edited by Cyril M. Harris.

29. Crandell, C. (1993) "Speech recognition in noise by minimal degrees of sensorineural hearing loss," Ear and Hearing, 14 (3), 210-216.

30. Finitzo-Hieber, T. and Tillman, T. (1978) "Room acoustics effects of monosyllabic word discrimination ability for normal and hearing impaired children," Journal of Speech and Hearing Disorders, 49, 409-418.

31. Effect of Reverberation Source: http://www.phonakpro.com/content/dam/phonak/b2b/FM_eLibrary/ ACCESS_Chapter_22_Arthur_Boothroyd.pdf

32. Critical Signal to Noise Ratio • Is the SNR at which 50% of speech is understood Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

33. Critical Signal to Noise Ratio • Is the SNR at which 50% of speech is understood • Most clinics don’t measure this directly Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

34. Critical Signal to Noise Ratio • Is the SNR at which 50% of speech is understood • Most clinics don’t measure this directly • Varies from -6 dB (normal in adults) to +15 to +20 dB (profound) Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

35. Critical Signal to Noise Ratio • Is the SNR at which 50% of speech is understood • Most clinics don’t measure this directly • Varies from -6 dB (normal in adults) to +15 to +20 dB (profound) • Children with relatively mild hearing losses can have profound SNR loss Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

36. Critical Signal to Noise Ratio • A 1 dB SNR loss can result in a 10-20% decrease in speech intelligibility • An SNR loss of only 3 dB can already have a severe impact on a child’s ability to understand speech in the classroom. • This is consistently underestimated by educators ! Adapted from: Phonak Introduction to FM (http://www.phonakpro.com)

37. SNR Gram Source: Phonak Introduction to FM (http://www.phonakpro.com)

38. SNR Gram Source: Phonak Introduction to FM (http://www.phonakpro.com)

39. Speech Intelligibility and SNR Source: Phonak Introduction to FM (http://www.phonakpro.com)

40. Speech Intelligibility and SNR Source: Phonak Introduction to FM (http://www.phonakpro.com)

41. Critical SNR and Hearing Loss There is a lot of variability, it’s still important to measure it.

42. FM systems: Rationale • Children need a better signal to noise ratio than adults • Adults: Good speech intelligibility at +6 SNR • Children: Need an SNR of 15-20 dB to do as well • No acoustic treatments can provide this. Only FM can. • A typical classroom has an SNR of +4 dB, and it may be as low as 0 dB.

43. Personal FM systems • Usually coupled to a BTE hearing aid but not always • Provides the best and most consistent signal to noise ratio (+ 15-20 dB) for the teacher’s voice

44. Personal FM systems • Almost always used in FM + Mic setting, so that the child can hear other students not just the teacher

45. Soundfield FM systems • One speaker is placed towards the front of the room. • Amplifies the level of the teacher’s voice slightly. • Does not single out the hard of hearing child as being different from the others in the classroom.

46. Distance and SNR Even in the front row conditions are not very good. Source: Phonak Introduction to FM (http://www.phonakpro.com)

47. Distance, SNR and Personal FM Source: Oticon pediatrics

48. Other Uses of Personal FM • To give a child with severe/profound hearing loss better access to all of the sounds of speech • Parents • Caregivers • Speech-Language Pathologists • Teachers of the deaf and hard of hearing

49. Other Uses of Personal FM • Input + Hearing aid gain = Output • Example: An output of 80 dB is needed to hear /s/ sound, and level of /s/ is 30 dB. 30 dB (input) + 40 dB (gain) = 70 dB (not audible) With FM, input level increases by 20 dB.

50. Soundfield FM systems • Does not provide as good an SNR as personal FM • Installation can be complicated, especially in reverberant rooms (late reverberation)