EarlyInteractionandNonverbalCommunication

EARLY INTERACTION AND NONVERBAL COMMUNICATION INTRODUCTION Young infants and babies are not able to communicate by words in the way adults can. As a substitute, they use natural gestures, facial expression and vocalization, which are general. At the earliest stage, these are gross to start with - cries or wriggles – but their methods become more and more exact as they grown-up and their sounds amalgamate into words. Interaction with responsive adults is must to develop their communication. Early interaction and Communication: Early interaction: Early interaction refers to the interaction between an infant and caregivers before development of verbal speech and language. The word infant is derived from the Latin infans, which means, “ not speaking”. But a lot of communication occurs before verbal speech and language develop. Development of language depends on the development of earlier preverbal (before speech) interaction and communication. (Owens, 2001, pp.157) Communication: “Communication is a natural way in which people exchange ideas, ask for something or someone, comment on what is happening around them and express their feelings.” (Crishna, 1996, pp. 1) In case of infants – communication is the way in which they can request, protest, greet, comment, and ask for objects, attention, action etc. “ Communication does not suddenly start when the child begins to talk; it has been taking place from the moment he was born. Often the child and the adult may be quite unconscious that what they are doing is communicating.” (McConkey, 1986, pp. 41) People/children usually communicate- 1) By using speech: It refers to the verbal expression in a language that is realized by other surround the child and includes- Words ­­­­­­­­­­­­­­­­­­­­­­­­­----------- Hello Phrases ----------- Hello, Mina Sentences ----------- Mina is sitting on the table 2) By using non-verbal means: Sound - which express happiness or sadness or a . response Eye gaze - by looking at an object when infants want it Facial expression - by smiling when infants are happy Body language - by turning away from things they do not like Pointing - by pointing with a finger or a hand to a person Gesture - by waving their hand to say hello Touching - by touching anybody to get attention (Crishna, 1996, pp. 2-3) We can say that though speech is most accepted and normal form of communication, it develops later after using a lot of non-verbal means in a child. These early non-verbal skills are very essential for a child in acquisition of language. Early interaction between infant and mother occurs with these non-verbal forms of communication. For example- non-specific crying which could indicate a need for food or comfort or relief from pain, But the mother or the caregiver, responds to this early, unclear message by trying to find out what the child wants. The mother may get that the child is hungry, wet, cold, pricked by a safety pin or plagued by a pain in his stomach. Stages in Early Communication Development: Between birth and age one · Can differentiate mother’s voice from stranger’s voice. · Cries to gain contact/cries for assistance, when happy/uncomfortable/in pain/ hungry (reinforced behavior) · Increasingly, chronological rather than instantaneous speech begins to develop. · Improved turn-taking outline (pauses for response) · Rituals and game-playing develop · Rituals (conventional routines of feeding bathing etc.) · Games = anticipation-based (Peek-a-boo, round the garden) · These sequences of mutual gaze, smiles, and vocalization are like “protoconversation” (similar to conversation) · Recognizes and responds to own name · Interactions become more about the infant, caregiver and an object (i.e. triangle reference) · Recognizes name of familiar people (mum, dad) · Says 2-3 words besides "mama" and "baba". · Use simple social gesture, e.g. wave bye bye, clap · Turns to search and localize used words such as all gone, no, bye bye (Bangla-shes, na, bye bye) Between one and two · Understands "no". · Uses 20 to 40 words, including names. Uses new words regularly. Removes shoes, socks, pants, and sweater Replaces familiar objects where they belong Sleeps ten-twelve hours at night Refers to self by name. Combines two words such as "daddy bye-bye". Waves good-bye Plays by self; initiates own play Builds tower of 6-7 blocks. Makes the "sounds" of familiar animals. Uses word such, as "more" to make wants known. Brings object from another room when asked. Between two and three Identifies body parts. Gives full name. Holds up fingers to tell age. Carries on 'conversation' with self and dolls. Asks, "What's that?" And "where's my?" Uses 2-word negative phrases such as "no want". Has a 450-word vocabulary. Combines nouns and verbs "mummy come". Understands simple time concepts: "last night", "tomorrow". Refers to self as "me" rather than by name. Tries to get adult attention: "watch me". Likes to hear same story repeated. May say "no" when means "yes". Talks to other children as well as adults. Solves problems by talking instead of hitting or crying. Answers "where" questions. Matches 3-4 colors, knows big and little Names common pictures and things. Uses short sentences like "me want more" or "me want biscuit". Between three and four Uses verb forms. Uses 'I', 'you'. Uses 'this', 'that'. Names at least one color. Counts to five. Verbalizes recent experiences. Can tell a story. Understands 'what', 'where' Uses 'what', 'where' and occasionally 'when', 'who'. Has a sentence length of 4-5 words. Has a vocabulary of nearly 1000 words. Understands "yesterday," "summer", "lunchtime", "tonight", "little-big". Begins to obey requests like "put the block under the chair". Knows his or her last name, name of street on which he/she lives and several nursery rhymes Between four and five Has sentence length of 4-5 words. Uses past tense correctly. Comprehends the concept of 'better than'. Uses size and colour adjectives in sentence form. Has a vocabulary of nearly 1500 words. Points to colors red, blue, yellow and green. Identifies triangles, circles and squares. Understands "In the morning", "next", "noontime". Can speak of imaginary conditions such as "I hope". Asks many questions, asks "who?" and "why?" Outline of stages of early communication: Perlocutionary stage 0-8 months: · Infant has no goal awareness · Attends to and responds to stimuli · Uses undifferentiated behaviors (e.g. crying) · Deliberate communicative attempts increase gradually (gestures, reaching) Illocutionary stage 8-9 months: · Coordinated plan to achieve goals · Infant uses eye contact and repetition · Uses gestures · Uses protoimperatives (requests-reaching, pointing) · Uses protodeclaratives (maintaining joint attention-pointing, showing) Locutionary 12 months: · Begins with first meaningful words and gestures together · Words accompany or replace gestures to express · Symbolic interaction occurs · Elicited speech sounds sometimes words STAGES OF EARLY COMMUNICATION Coupe and Goldbart (1988) discuss 6 stages of early communication. These are- Stage 1. Pre-intentional-Reflexive stage: The carer to the individual’s very early and reflexive behaviours assigns communicative intent and meaning. These are produced in response to internal and external stimuli (especially auditory and visual stimuli) eg. Startle reflex, sucking reflex. At the reflexive level, the person appears to sleep a lot. However, when awake the individual will gaze at people or objects, which come into his or her visual field (15-20 cm). When the caregiver makes eye contact with the individual it is known as “mutual gaze. Stage 2. Pre-intentional-Reactive stage: The carer to the individual’s reactive behaviours assigns communicative intent and meaning. The individual reacts to people objects or events within his or her environment. He or she reacts to stimuli from all senses. There is now an expanded range of body and lime movements and vocalizations e.g. trunk turning, hand to mouth behaviours and a greater variety of facial movements. He or she learns to repeat a pleasurable action. The carer will talk to the individual and the content of the conversation will relate to the activity that they are involved in e.g. “Here is your dinner’’- at dinner time. The individual responds to different tones of voice and to different facial expressions. He or she will search for sound sources, especially speech or music. Any sound or movement made by the individual will have a major effect on the carer’s behaviour. At this stage, the first smile appears. Mutual gaze is changing and leading into shared attention where the individual and the carer may appear to be “looking” at the same object or event and the carer will comment on it. Stage3. Pre-intentional-Proactive stage: The individual’s efforts to act on the environment become signals to the carer who then assigns communicative intent and meaning. At this stage, there is the beginning of acting purpose fully on objects. The individual begins to realise that objects exits even if they cannot see them. He or she can retrieve partially hidden objects and can recognise some objects by function e.g. cup/drink. The individual will look for reach for desired objects and people. A repertoire of different behaviours is developing, for instance, hitting, shaking and mouthing various objects. He or she will attempt to repeat actions, which brought about novel changes. The individual can shift his or her attention to more than one thing at a time. He or she is beginning to understand another person’s expressions and actions. The individual will also continue a movement during a pause in familiar interaction e.g. If being rocked, s/he will continue the rocking a break as a signal to reinstate the movement. He or she begins to imitate simple gestures e.g. waving, clapping. Towards the end of stage, the behaviours become more intentional the individual sees what he or she wants and goes for it, although the way he or she does it may not always be successful. Stage 4. Intentional-Informal stage: The individual acts on the environment to create a specific effect. By the time the individual reaches the early intentional stage of development he or she knows how to use an object to get the carer’s attention or how to use another person to get an object that he or she wants. Object permanency is established and the individual will actively try to look for objects that disappear. He or she will also use a repertoire of behaviours including alternating gaze to get his or her needs met le. Looking back and forth between the communication partner and the item or activity that is wanted as a way of requesting it. There begins to be a range of communicative functions e.g. protests, greeting, positive and negative attention seeking. Receptively, the individual recogninises and responds to common gestures e.g. come here, go away, wave. He or she also shows simple imitation skills. Stage 5. Intentional-Formal stage: At this stage the individual is beginning to integrate the information from his/her senses. He or she will drop or throw something deliberately, monitor the action and look to see where it falls. The individual is more able to solve problems through trial and error. Objectives are beginning to be used appropriately e.g. use of a straw, a comb, a purse. The individual learns that the same object will do different things depending on how it is used e.g. papers tears, paper crumples. Reaching for something turns into pointing to something. The individual is able to communicate a wide range of intentions or functions to others in a way that is more conventionally understood e.g. through gestures, single words and vocalizations. He or she will show or give objects as a way of initiating or maintaining an interaction with another person. He or she will understand the key words in a sentence particularly when used in context. Stage 6. Intentional-Referential stage: The individual starts to have an internalized mental representation of the word around them; He or she is able to solve simple problems by thinking about them rather then through trial and error. Deferred imitation skills are established e.g. can imitate unfamiliar actions after an event. The individual may also be able to mime or act out an event. Joint action routines are established where the individual learns that interactions follows a familiar sequence of events and can anticipate these and indicate when the sequence is varied e.g. dressing, grooming, mealtimes. For instance, with dressing- the caregiver uses the same order- singlet first, then t-shirt or jumper, underpants, socks, pants and shoes. The function of a range of objects is known and objects are used purposefully. Objects may also be used to established or maintain a social interaction or because he or she needs help with an activity e.g. bring a key to open cupboard where a favourite item is kept. Hierarchy of learning language: Speech Expressive language Receptive language Play Attention Interactional Behaviors: Some interactional behaviors are essential for communication development of a child. These are- Joint reference: Also known as “joint attention”. Joint reference means- two or more individuals share a common focus together on one point of interest (object/event/person). (Owens, 2001, pp.184) The baby and mother insert in a system to ensure joint selective attention at earliest stage. For an example, the mother will shake an object before her infant to be a focus for the infant’s attention it. These routines are accustomed to achieve eye contact, the first step in Joint reference. Joint action: Infant and the caregiver build up dual behaviors in a familiar context through out the first year of life. The routinized actions (i.e.- game playing and daily routine) are called joint action. Conversational skills and turn taking are learned. Rules of communication can be learned within a familiar and pleasurable social sequence. Game playing: Caregiver and the infant begin to play almost from birth. Depending on caregivers and child’s interest, the games become ritual exchanges that mention upon or sensitively mark common patterns of interaction. Routines: It means- the conventionalized and predictable scripts or scaffolds for interpretation and behaviors in which caregiver provide order. Conceptual foundations of later language development is achieved within familiar daily routines and events (bathing, toileting, dressing, feeding etc.) Turn taking: Turn taking is very essential aspect of interactional behavior for rurther development of conversational skills that is language development. It occurs in early breast-feeding. A ‘turn” may entail vocalization, movement of body parts, facial expression etc. It occurs in games with pauses for infant responses (tickling, lifting, bouncing etc.). It develops protoconversation (similar to conversation) with alternating vocalization, then gestures and words. Babytalk/motherese/parentese: Motherese is a special style of talking with children which contains short and simple form of sentences, special body movement and special facial expression. Characteristic of motherese: · Small core vocabulary · Short length of utterance · Infant vocal behavior is treated as meaningful · Much use of verbal rituals and repetitions · Talk refers to the here and now · Much use of greetings · Mother pauses even if the child doesn’t respond · Much use of pitch and loudness Activities to Encourage your Child's Language Encourage the child to express opinion by using gesture Talk simply, clearly, and slowly to your child Give him/her opportunities to make choice Play simple games with your child Comment on what you did or how you think your child feels. Talk to your child as you care for him or her throughout the day Use a lot of pictures Tell rhymes and sing songs. Allow the child to use symbolic or invented word e.g.- mew sound to indicate cat Talk to your baby about everything you're doing while you're with him/her Reward and encourage early efforts to communicate Give reinforcement for child’s response Continue to say social stories. Praise your child when she talks about her feelings, thoughts, hopes and fears. Look at family photos and talk to him about your family history. Listen to her when she talks to you or tries to express something. GLOSSARY Approximate- near, estimated Blink- flash Core- center, middle Dissimilar- different Exact- precise/accurate Increasingly- gradually Imitation- reproduction Intentionality- goal directed behavior Interaction- interface, contact, relation Manipulation- handling, management Non-intentional- not goal directed or purposeful Overhang- protrusion Preverbal- before speech Protest- objection, complain Prick- puncture, perforation Plagued- beset Predilection- preference, liking, fondness Pause- silence Pitch- terrain Predictable- expected Protoconversation- similar to conversation Quiver- tremble, shake Ritual- formal procedure Repetition- echo, recurrence Remoteness- distance Retort- comeback with, rejoin Responsive- approachable, reactive Reflexive- automatic, impulsive Stimulate- arouse, inspire Settle- clear up Startle- surprise, shock, alarm Substitute- alternate Significance- importance Stiffen- harden Tickle- irritate, prickle Unconscious- unaware Wriggle- writhe REFERENCES 1) Owens, R.E. (2001), Language Development: An Introduction, 5th Ed, Boston: Pearson Education, pp. 157-194 2) McConkey, R. & Price, P. (1986), Let’s Talk, London: Souvenir Press (E & A) Ltd., pp. 41-80 3) Crishna, B. (1996), Communication for the child with Cerebral Palsy, Calcutta: Indian Institute of cerebral palsy, pp. 1-6 4) Bloom, L. & Lahey, M. (1978), Language Development and Language Disorders, New York: John Wiley & Sons, pp. 69-97. 5) Coupe, J. Golart, J. (1988), Communication before Speech, London: Chpham and Hall, pp. 19-30 6) Sheridan, M., (1997), From Birth to Five years, London: Routledge.

AUDIOLOGY- TYMPANOMETRY

TYMPANOMETRY



1) Tympanometer

Definition:

A tympanometer is an instrument, which provides information on the functioning and status of the middle ear.


2) Tympanometry:

Definition:

Tympanometry is an objective test and as it requires little cooperation, it can be carried out at any age and with any degree of deafness. It always for the measurement of the elasticity or compliance of the introduced into the middle ear system.

Tympanometry is one of three principal subtests of immittance audiometry. Immittance audiometry is an objective procedure that assesses, in an individual ear, the relative impedance (resistance offered to the flow of energy in acoustics signals) and admittance or compliance (the reciprocal of impedance, and the case with which the ear accepts the flow of energy in an acoustic signal). The other two subtests of immittance audiometry are static admittance/ compliance and the acoustic reflex test. The general term ‘immittance’ is used to indicate the principle of evaluating energy flow. Particular test equipment may measure either impedance or admittance.

Explanation:

Tympanometry assesses the ability of the tympanic membrane to accept sound, and is therefore a test of the conductive mechanism of the ear. It is a dynamic measure, meaning that the tympanic membrane is in motion during the test. The basic approach in tympanometry is to introduce a pure-tone (usually 220 Hz or 660 Hz) into the external auditory meatus and to measure how much of that sound wave is accepted (admitted) or rejected (impeded) by the tympanic membrane. In a normal ear the tympanic membrane will accept most of the sound and will do this when the air in the external auditory meatus is at or very close to normal atmospheric pressure.
During tympanometry, air pressure, expressed in decapascals (daPa) or millimeters of water (mm water), is varied continuously in the external auditory meatus from values greater than normal atmospheric pressure (usually + 200daPa/mm water), through normal atmospheric pressure (0 daPa/mm water), to values less than atmospheric pressure (usually- 200 daPa/mm water). This causes the tympanic membrane to move in the response to the positive and negative pressure allied to it.


3) Tympanogram-

Tympanometry results are plotted, either automatically or manually, on a tympanogram, a graph of impedance/admittance values against air pressure values.
By using handtymp we can get the tympanogram. It is very important to hold the handtymp properly. We have to set the tip in right position. Other wise it would be difficult for anyone to get the tympanogram. Then we can press the button until the pick showing. Thus we can have the result of the tympanogram. From this we can know air pressure, canal position, eardrum mobility etc. If the pick is in the range of 0.35-1.4 the compliance is normal. If the pick is in the range of –100-+50 the middle ear pressure is normal. And for other range it is not normal.


4) Instructions for the tympanometry

We should follow these instructions for the tympanometry-

a) Tympanometry may be carried out in almost any reasonably quiet room.
b) As very low levels of ambient noise are not required, although the British society of Audiology recommends that the ambient room noise be less than 50 dB A SPL, if possible (BSA, 1992).
c) The range of equipment available is considerable.
d) Glove should be used during middle ear testing.
e) An auroscope or otoscope is required for inspection of the external auditory meatus.
f) The tympanometer should be hold in proper way
g) The button of the tympanometer should be pressed until the pick showing.
h) The tip of the tympanometer should be set correctly in the ear.
i) Tip size will be well fitted for the client
j) Different tip for different client
k) All of the equipment will be neat and clean
l) Before starting test we have to check all of the equipments.
m) Set up the room and equipment to ensure satisfactory hygiene and client co-operation.
n) Washing hands and follow other hygiene protocols as appropriate

5) Instructions for testing the client

We have to always follow the instruction for testing the client-

a) Explain the test and instruct the client.
b) Inspect the pinna visually and the external auditory canal with an otoscope to determine the size and angle of lateral portion and to check for any contraindications to tympanometry.
c) Contraindications include discharge from the ear, wax occlusion, tenderness of the ear, foreign bodies and obvious perforation or inflammation of the tympanic membrane (ASHA< 1990c; BSA, 1992)
d) Select an appropriate sized probe tip for the client.
e) For all the things we have to get permission from the client.
f) Asking the client to open their mouth, and pull the pinna upwards and backwards
g) These actions will straighten the lateral, cartilaginous portion of the external auditory canal and make insertion easier.
h) If using an automatic tympanometer, the instrument will indicate whether or not an airtight seal has been obtained.
i) Inform the client of the result, taking care not to interpret beyond the available data.
j) Keep appropriate records, ensuring that the date of tympanometry screening is recorded.







References



a) Doyle, J., (2002), Practical audiology for Speech-language therapy, Whurr Publishers, London.

b) Bess, F.H.; Humes, L.E.; (1990), Audiology the Fundamentals, Wiliams & Wilkins, Baltimore.

c) Tucker, I.; Powell, C. (1991), The Hearing Impaired Child and School, A condor book, London

Hearing Aid

Hearing aid



Definition:


Hearing aids are electroacoustic instruments that improve the audibility of speech and other important signals for the person with hearing loss. (Doyle, 2002)

The aim is to amplify the volume of the signal to a level that is, on average, above the individual’s hearing threshold and below that individual’s level of discomfort, so that the signal is comfortably audible, and to do so in a way that maximizes the intelligibility of speech signals.


Parts of a hearing aid


Hearing aids come in many shapes and sizes but they all have the same basic components.

The main parts of any hearing aid are:

1) Microphone
2) Amplifier
3) Lead (or cord)
4) Receiver (earphone)
5) Earmould
6) Battery
7) Volume control
8) On-off switch

In addition to the above components many hearing aids also have:

9) Tone control (may be inside)
10) Telecoil (T switch)
11) Maximum output control (Inside)
12) Gain control (Inside)
13) Audio input connection

The inside controls are for the audiologist to set, not for the wearer to adjust himself.

How does it work?

1) The microphne picks up sound from the environment and converts it from an acoustic signal to an electronic signal.
2) The amplifier processes and amplifies the electronic signal.
3) The receiver works like a speaker and converts the amplified electronic signal back to acoustic signals.
4) The sound is delivered to the ear canal through a tube in the earmould or via the hearing aid shell
5) All hearing aids require a battery to supply power to the system
6) The amount of amplification (or gain) is varied by means of the volume control.
7) The on/off switch turns the hearing aid on or off (Some times there is no separate on/off switch but the aid is turned off by the volume control)
8) When telecoil is in use the aid can pick up electromagnetic signals from a telephone or inductive loop.
9) Low cut tone control gives more high frequency emphasis by cutting the low frequency signals. It is sometimes used to cut background noise.
10) High cut tone control gives more low frequency emphasis by cutting the high frequency signals. It is sometimes used to reduce background noise.
11) The maximum output control (or peak clipping) limits the maximum intensity of sound that the aid will deliver.
12) The gain control reduces the maximum amplification.
13) A means for conection the aid directly to an FM radio receiver or other external device.

Types of hearing aids:


Hearing aids are most commonly classified by style, which is closely related to the size of the instrument. There are five basic types of hearing aid available today. These are-

1) Body-worn or Pocket hearing aid
2) Behind-the-ear (BTE) or Post-aural hearing aid
3) In the ear (ITE) aid
4) In the canal aid
5) Eyeglass or Spectacle aid

The Bone conduction hearing aid, Radio frequency (RF) or Frequency modulated (FM) are additional hearing aids.


When electroacoustic hearing aids were first developed several decades ago, the body aid was only type available. In the ensuring years, the other types of instrument were developed, with BTE hearing aids being the most common in the 1970s. During the 19980s, the trend has been for ITEs to capture an increasingly larger portion of the hearing aid market. The increasing popularity of the ITE and ITE and ITC hearing aids is a result of both consumer pressures to improve the cosmetic appeal of the devices and rapid developments in the field electronics. High fidelity electronic components and the batteries to power them have been drastically reduced in size, making the in the ear devices possible.


Description of various types of hearing aids:


1) Body-worn or Pocket hearing aid:

The largest and least frequently fitted aid is the body level hearing aid, which is worn clipped on to clothing, generally at chest level. The signal that is picked up and amplified in the body worn aid is fed to a receiver attached to a standard earmould. Because the microphone (Input transducer) and the receiver (output transducer) are a considerable distance apart, very powerful amplification may be provided with little risk of acoustic feedback. Even though powerful amplification is now available in much smaller aids, body-level aids remain appropriate for some individuals, particularly those who require very large controls because of reduced manual dexterity and/or poor vision.

2) Behind the ear (BTE) or Post-aural hearing aid:

In behind the ear (BTE) hearing aids all components are worn at ear level. The microphone, generally level with the top of the ear, is thus in a more natural position than it is in body aids. Even individuals with profound hearing losses may be fitted with BTE aids. Earmould styles and materials in BTE aids can vary greatly and are an important part of the sound delivery system. The same hearing aid can produce very different results with different earmoulds.

3) In the ear (ITE) aid:

In the ear (ITE) aids house all components in a custom made shell, which fits into the concha and external auditory meatus. The size of ITE aids varies with the size of the individual’s ear and the desired features. In the canal (ITC)


4) In the canal aid:

In the canal (ITC) hearing aids provide all components in a custom made shell that occupies the ear canal and less of the concha. The smallest aids are completely in the canal (CIC) aids, which are effectively not visible. There are some exciting developments in amplification with CIC. Deep canal hearing aids sit partly down in the bony portion of the ear canal and this appears to provide relief from the occlusion effect experienced by aid users who complain about how they hear their own voice.

Many smaller hearing aids cannot provide features (such as telicoil) beyond the standard microphone, amplifier, battery and receiver because of space limitation.

5) Eyeglass or Spectacle aid

Eyeglass or spectacle aids provide amplification through hearing aids built into the frame of spectacles. The amplified signal is fed via a tube to the ear canal. Spectacle aids may or may not be worn with earmoulds, depending on amplification.

Others:

Radio frequency (RF) or frequently modulated (FM) hearing aids are instruments in which the microphone is positioned at the sound source rather than at the ear of the listener. A type of aid that is fitted very infrequently is the bone conduction hearing aid, in which an oscillator placed on the mastoid and held in place by a spring steel band over the head replaces the output transducer. An advance on present situation is the implantable bone conduction aid (IHA) or bone anchored hearing aid (BAHA).


Hearing aids also can be classified as:

1) Analogue
2) Digital

1) Analogue:

Most hearing aids currently use ‘analogue’ circuits. These have developed a lot from the old ‘class A’ amplifiers and ‘class B’ push-pull amplifiers found in more powerful hearing aids (eg powermaster). Many aids now have ‘class D’ amplifiers in compression circuits.

2) Digital:

In the last few years a new range of hearing aids has been developed which use digital programming of analogue circuits. The aids are adjusted with the help of a computer. This often makes it easier to modify the frequency response according to the user’s audiogram.

The latest hearing aids use digital signal processing (sometimes called DSP or 100% digital). The electrical signal is converted into digital information and then ‘processed’ before being converted back to an analogue electrical signal and then into sound by the receiver.

One advantage is the lack of internal electrical noise. It is also possible to devide up, manipulate or ‘process’ the signal much more easily than with an analogue circuit.


Advantages of hearing aids:

Body worn hearing aids:

• Does not break easily.
• Cheap in rate
• Battery is available
• Easy to carry
• Safe for the client
• Easy to identify the problems

Behind the ear hearing aids:

• Not very visible
• Nice to look
• Need not wear in the body
• Can receive sounds from around of the client
• Modern pattern
• Very lightening
• Comfortable


Disadvantages of hearing aids:

Body worn hearing aids:

• Very visible
• Old fashion
• Does not look nice
• Not modern pattern
• Need to wear like a dress
• Not very comfortable
• Cannot receive all the sounds

Behind the ear hearing aids:

• Not cheap
• Battery is not available
• May break easily
• Repairment is not very easy
• Difficult to clean


Care and Maintenance of hearing aids:

Microphone:

a) The microphone is most effective within a distance of about 3 feet. Small children should wear their pocket hearing aids in a specially made belt or harness. This keeps the aid securely in the correct position.
b) With small children it must be protected from dirt, spiled food, drink etc by a baby cover
c) The microphone works on M setting (not T)
d) Switch off when not in use to save batteries.

Amplifier:

a) This consists of electronic components inside the case. They must be kept clean and dry.
b) The volume control determines the amount of amplification (or gain)

Cords (or leads):

a) A break in the lead sometimes causes an intermittent signal. (Sometimes on, sometimes off)
b) There should be no knots in the lead.
c) When the aid is not being used, the cord should be coiled correctly and loosely.
d) Different length cords are usually available. Try to get short cords for little children.

Receiver:

a) The receiver may be either 2 or 3 pin. It is matched to the aid. Do not allow children to exchange receivers.
b) If possible use a small size receiver with little children
c) Receivers are not easily damaged unless they get wet. Do not allow children to put the mouth.

Earmould:

a) This must be tight fitting or feedback and whistling occurs
b) Earmoulds must be kept clean. They should be removed from the receiver or hearing aid elbow and washed carefully in warm soapy water. They must be dried very carefully before replacing.
c) The tubing will need to be replaced about every six months

Batteries:

a) Pencil batteries run down gradually and must be changed frequently before they are drained.
b) Dead batteries must not be left in the hearing aid.
c) Post aural button batteries cut out suddenly. Spare batteries should be carried always.
d) Note that small button batteries contain poison. They must not be swallowed. Keep them away from babies.








References



a) Doyle, J., (2002), Practical audiology for Speech-language therapy, Whurr Publishers, London.

b) Bess, F.H.; Humes, L.E.; (1990), Audiology the Fundamentals, Wiliams & Wilkins, Baltimore.

c) Tucker, I.; Powell, C. (1991), The Hearing Impaired Child and School, A condor book, London