the three physical properties of sound are frequency, amplitude and timbre
- frequency refers to the number of complete cycles made by a sine waves and is measured in
o Frequency is PERCEIVED as pitch.
o A high pitch sound corresponds to a high frequency sound wave and a low pitch sound
corresponds to a low frequency sound wave.
- amplitude refers to the difference between the peak and trough of the sound wave and is
measured in decibels.
o Amplitude is PERCEIVED as loudness.
o A high amplitude sound is loud, a low amplitude sound is soft.
- timbre refers to the shape of the waveform
o timbre is perceived as the quality of the sound
o it allows the human ear to distinguish those sounds which have the same frequency and
c) oral approach involves enhancing hearing to the best extent possible and teaching children oral
english language skills
-> Methods for enhancing hearing
- hearing aid is a device that amplifies the sound to help individual with hearing aid to hear more
clearly. However, depending on the hearing loss not everyone can benefit from them. Moreover, all
sounds will be amplified, including the background noise.
-fm system has been developed to overcome the problem of background noise. It uses FM radio signals
to deliver louder and clearer sounds from the teacher directly to the student. While the microphone in
hearing aid is located at the child’s ear, the microphone in fm system is located where the teacher
speaks. As a result, only the teacher’s speech is amplified.
- cochlear implant is surgically implanted device which provides the sense of hearing to individuals
with severe to profound hearing impairment. Unlike hearing aids and fm system, it does not amplify the
sound but rather bypasses the damaged structures inside the middle ear directly stimulating the
auditory nerve. The brain interprets this info as sound.
b) causes for speech delay
1. partial or complete hearing loss - the child will not be able to pronounce the sounds that he/she is
unable to hear; the child will not be able to monitor own speech adjust it accordingly (the child might
have articulation error errors that he/she might not be aware of); the speech will have limited vocab bc
the child will have more difficulty classically conditioning the sounds with the physical objects 2. defective learning opportunity - for example in the family where the parents are depressed and not
speaking to the child, he/she will not be able to speech bc not receiving ling input
3. negativism - when there is a discrepancy btw the expectations of the family and the ability of the
child . The child may as a result refuse to speak. ie if the child is expected to say something in front of
the whole family and the child is not comfortable with it -> will not speak
4. emotional disturbance, brain injury or intellectual disability - might not speak bc hurt inside
- visual field is a proportion of space that one can see with a fixed eye. tunnel vision is a restricted field
of vision. While normal field of vision is 180 degrees, person with tunnel vision can see 20 degrees or
less. it is as though he/she is looking through the role of toilet paper.
- legal blindness - condition in which the visual acuity is 20/200 in the better eye with correction or
when the visual field is 20 degrees or less. if individual has tunnel vision -> will be legally blind bc
satisfies one of the requirements
- will read norally bc has normal visual acuity. person has see at 20 feet what an average person can
also see at 20 feel. will not need large print bc only people who have poor visual acuity will need large
- braille is the writing system for the blind, composed of combination of 6 dots raised on paper which
can be read with fingers -> since person has good visual acuity will not need braille
refractive problems (accommodation) - caused by irregularities in the formation of the imaged on the
retina or transmission of the images to the brain
1. myopia - nearsightedness; individual is able to see near but cant see far
- cause - eyeball is too long or the lens (and/or cornea) are too curvy as a result of which
the image is focused in front of the retina
2. hyperopia - farsightedness; individuals are able to see far but cant see near
- cause - eyeball is too small or the lens (and/or cornea) are too flat as a result of which
the image is focused behind the retina
3. astigmatism - irregularities in the surface of the retina or lens which prevent the light srays
from focusing on the retina; the horizontal and vertical light rays focus at diff points on the
retina; causes blurred vision
4. presbyopia - lens lose their ability to accommodate to near objects; people over 40 usually
develop some degree of presbyopia and require glasses for close work
all can be corrected with glasses, lenses as well as lasik surgery
c) 20/30 vision - visual acuity is worse than normal; person can see at 20 feet what an average person can
see at 30 feet
will need optometrist to prescribe eye glasses of lenses
optometrist - specialist (not doctor) trained to measure visual function related to the prescription of
lenses or glasses
since doenst have eye pathology will not need ophthalmologist - doctor who specializes in eye diseases