APPENDIX

A.1 - Sound Range of the Ear and Range of Hearing loss

Decibel

Category of Hearing Loss

Mild Hearing Loss
(26dB to 40dB)
Moderate Hearing Loss
(41dB to 55dB)
Moderately Severe Hearing Loss
(56dB to 70dB)
Severe Hearing Loss
(71dB to 90dB)
Profound Hearing Loss
(Over 90dB)

 

A.2 - Category and Range of Hearing Loss and Communication Ability

Category and Range of Hearing Loss

Communication Ability

Mild Hearing Loss
(26dB to 40dB)

Hard to identify soft sound but capable ofgeneral communication.

Moderate Hearing Loss
(41dB to 55dB)

Hard to receive voice over 2 meters. The use of hearing aids can improve receptive power.

Moderately Severe Hearing Loss
(56dB to 70dB)

Hard to hear soft voice in general communication. Should use hearing aids to improve reception.

Severe Hearing Loss
(71dB to 90dB)

Hard to communicate fluently with people. Speech is deflected.The use of hearing aids is crucial in communication. Lip reading improves reception.

Profound Hearing Loss
(Over 90dB)

Speech is deflected and possibly language is deviant. Communication with people relies heavily on the use of hearing aids and lip reading.

 

A.3 - APPENDIX 3

A.3.1 Individual Hearing Aids :

無線個別助聽儀器

Wireless Individual Hearing Aid

The Wireless Individual Aid allows the hearing impaired children with greater mobility to join in the classroom activities.

人工耳蝸助聽系統

Cochlear Implant

An artificial cochlear is implanted into the ear by surgery. After the operation, the implantee still needs to wear the speech processor and transmitter to transfer voices into electric impulse.

耳後助聽機

Behind the Ear hearing Aid

This is the most common type of hearing aid used by the hearing impaired children. This hearing aid amplifies sound for greater audibility.

無線組別助聽儀器

Radio FM Group Hearing Aid

There is a transmitter for the teacher and ten receivers for the hearing impaired children. During the lessons, the children receive the FM signal from the teacher without the obstacle of the wire. A greater mobility for activities in the classroom is allowed.

 

A.3.2 Group Hearing Aids in a Deaf School :

組別助聽儀器

Group Hearing Aids

The children's desks are arranged in a horse-shoe shape unit. There are ten sets of Pupil Unit on the desk.

耳筒及調校儀器

Headphone and Pupil Unit

Each set of Hearing Aid has a headphone and a pupil unit. Hearing impaired children can adjust the volume, tone and AGC according to their needs.

總機

Teacher Unit

The Teacher Unit in each classroom helps to control all the Pupil Units. Teacher can control the sensitivity level of the microphone in order to have the best output level to the Pupil Units.

無線組別助聽儀器

Radio FM Group Hearing Aid

The radio FM group hearing aid is used in the Primary classes. The FM wave transmits the signal from the teacher to the children without the obstacle of the wire. The children are provided with greater mobility to participate in the classroom activities.

 

A.3.3 Hearing Aids used in Speech Training Room :

語言訓練儀器

Speech Trainer

There are speech rooms in the deaf schools. The speech trainer in the speech room can be adjusted to meet the auditory needs of the child. The teacher can communicate with the child using the microphone. The child can also input his own speech with the help of the microphone.

視覺語言訓練儀器

Speech Viewer

This is a specially designed computer that provides attractive visual image to motivate the child to speak.

S - 指示器

S-Indicator

It helps to check the child's articulation of the /s/ sound.

 

A.3.4 Audiogram :

聽閾圖

Audiogram

An audiogram is a chart which locates the hearing threshold at different frequency. The horizontal axis reads in frequency (pitch) and the vertical axis reads in decibels (loudness). The frequencies are low on the left hand side (e.g. 125Hz) and the highest frequency (8000Hz) is on the right hand side. The loudness scale goes from very soft sounds (e.g. -10dB) at the top of the vertical axis, to very loud sounds at the bottom (e.g. 130dB).

An audiogram is prescribed by an audiologist. In Hong Kong, each audiogram of the school aged children is renewed every two years. An audiogram, which shows the residual hearing of the child, helps educators to plan the teaching objectives.

Legend of an audiogram :

The 'X' represents the hearing threshold of left ear. The 'O' represents the hearing threshold of right ear. The 'D' represents the hearing threshold of bone conduction.