hearing loss and implications for communication/language
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Hearing Loss and implications for Communication/language. The nature of sound Types of losses Possible causes of hearing loss Educational implications Preparing students for hearing assessment. The nature of sound. A wave phenomenon with two dimensions - PowerPoint PPT PresentationTRANSCRIPT
•The nature of sound•Types of losses
•Possible causes of hearing loss•Educational implications
•Preparing students for hearing assessment
The nature of sound A wave phenomenon with two dimensions
1. Frequency (Hz) - Hertz (cycles per second)- the number of vibrations of air particles per second: measured in Hertz- the human ear has a frequency range of approximately 20-20,000 - typically hearing is tested from 250-8000 Hz
Hz Low and high frequencies – impact on speech discrimination:
Psychological attribute which corresponds to frequency is pitch
Low frequency is perceived as low pitch and high frequency as high pitched sounds
Middle C on a piano is 250Hz, one octave below is 125 Hz
High pitched sounds include: a soprano voice, a doorbell
In general, vowel sounds are low-pitched and consonant sounds are high frequency sounds
2. The other dimension is intensity, measured in decibels (dB)“loudness”Usable hearing is from 0-120 dBdBs are intensity ratios20dB is not double of 10dB, but 100 times
greaterThe strongest sounds an average person
can hear without pain can be as much as 10 million times greater in intensity than a sound that is barely audible
For example:- 20 dB a whisper at four feet- 50 dB - quiet auto ten feet away-60-70 dB - normal conversation at three feet- 90 dB - pneumatic drill at ten feet
Speech acousticsSpectral characteristics make sound
complexVowels are lower frequency - generallly
having their most intense frequency components below 750 Hz
Consonants are composed of higher frequency sounds often consisting of a wide range of frequency components
In addition, vowels and consonants also differ in the amount of acoustical energy they produce
For an equivalent amount of vocal effort, the range between the loudest vowel (the o sound in the word dog) and the softest consonant (th sound) - is 28 dB
Vowels are therefore the most intense sounds heard in speech, while consonants are considerably less intense
However, consonants carry the most information
Consonants above 1000 Hz provide 60% of speech intelligibility, while vowels below 500 Hz provide only 5% of speech intelligibility
<Illustration>Thus, shouting at an individual with a
sensorineural hearing loss will do little to improve comprehension because the vowels will be the louder and the consonants will continue to be less audible
For this reason even mild hearing losses of 30-60 dB can have a big impact on speech intelligibility
Types of lossConductive
Sensorineural impairments
Mixed impairments
Central auditory impairment
Follow up to formal assessmentInterpreting audiograms - this is the role of
the audiologistThe job of the educational team is to get as
much information from the audiologist and the speech therapist about the nature of the speech sounds that the student can hear - with and without aids
Educational Decisions related to communication strategies for students with hearing impairments and deafness
Will you use visual aids?
Will you use a combination of gestures or signs and visual symbols?
Choosing a communication system – the issuesAmerican Sign Language (ASL)Oral languageCochlear implantsCombination approaches
Educational ImplicationsLiteracy: issues in teaching children who are
deaf to readSame language community issuesTeachers trained in working with
children/youth with hearing impairments and deafness
Social supports and friendship development
Least restrictive environmentParticipation in the core curriculum with
support for language and social engagementInterpreters, interveners, and support
teachersSigning community – same-language
community