HEARING IMPAIRMENT

HEARING IMPAIRMENTIntroduction to Special Education

HEARING IMPAIRMENTRefers to the reduced function or loss of the normal function of the hearing mechanism.Limits the persons sensitivity to tasks like listening, understanding speech, and speaking in the same way those persons with normal hearing do.According to the age of onset, hearing impairment can be congenital when the condition is present at birth or adventitious when it is acquired after birth or later on.When the condition occurs before the child learns to talk, deafness is prelingual.Deafness is postlingual when it is acquired after the child has learned speech usually at the age of two.DEAFNESSCannot use hearing to listen, understanding speech and communicate orally without special adaptations mainly in the visual code.

HARD OF HEARINGHas a significant loss of hearing sensitivity but he or she can hear sounds, respond to speech and auditory stimuli with or without the use of hearing aid.THE ANATOMY AND PHYSIOLOGY OF THE HUMAN EAR AUDITION act or sense of hearingThe ear is one of the two lead sense organs that allows a person to gather auditory stimuli and information from near and far sources in the environment that come in the form of acoustical energy.Audition transforms acoustical energy into a form called mechanical energy and finally into neural energy or nerve impulses that can be interpreted by the brain.Neural energy language of the brainEARThree main parts:External or Outer EarMiddle EarInner EarEXTERNAL or OUTER EARCalled the auricle or pinnaDirects the sounds into the auditory canal or external acoustic meatus. When sounds enter the external acoustic meatus, they are slightly louder or amplified as they are directed toward the middle ear.MIDDLE EARSounds enter the middle ear through the Eustachian tube and pass through the tympanic membrane or eardrum. The eardrum moves in and out response to changes in sound pressure. The movements of the eardrum change the acoustical energy into mechanical energy which is transferred to the three smallest bones in the body, the ossicles or ossicular chain, composed of the malleus or hammer, incus or anvil and stapes or stirrup. 7The footplate or base of the stapes rests in an opening called the oval window, the path through which mechanical energy enters the inner ear.

INNER EARThe vibrations of the ossicles transmit the mechanical energy from the middle ear to the inner ear with little loss.The most complex and sensitive part of the entire hearing apparatus, the inner ear is covered by the temporal bone, the hardest bone in the body. The cochlea is the main receptor organ for hearing and contains two fluid-filled cavities and the organ of Corti. The cochlea looks like a coiled shell of a snail. The vibrations stimulate the approximately 20,00 tiny hair cells to transforms the mechanical energy into electrical nerve impulses or neural energy.These impulses are transmitted along the auditory nerve through the central nervous system pathways to the brain where the auditory experience is processed and understood.The semicircular canals in the inner ear control the sense of balance.CLASSIFICATION OF HEARING IMPAIRMENTCONDUCTIVE HEARING LOSSOccurs in the outer and middle ear thereby blocking the passage of the acoustic energy.The blockage may be caused by abnormal growths or complications of the outer or middle ear.Malformation, incomplete development, or abnormal growth and improper movement of the ossicular chains can cause conductive hearing loss.If the inner ear is intact, conductive hearing impairment can be corrected through surgical or medical treatment.Hearing aid is usually prescribed.SENSORINEURAL HEARING IMPAIRMENTOccurs in the inner earThe sensitivity mechanisms and the auditory nerve may be damaged.When the cochlea is impaired, the neural energy delivered to the brain is distorted or not delivered at all.Audition does not take place and speech is not heard.May be congenital or adventitious because of illness or traumatic incidents.Only a very small percentage of sensorineural deafness can be reversed by medical intervention.MIXED HEARING IMPAIRMENTResults from combination of both conductive and sensorineural hearing losses.

CENTRAL HEARING DISORDERResults of any dysfunction in the central auditory nervous system between the brain stem and the auditory cortex in the brain.

Another basis for classifying hearing impairment is its being unilateral or present in one ear only, or bilateral or present in both ears.Degree of Hearing LossDecibel LossResulting ImpairmentNormal0 20 dBSlight27 40 dBFaint sounds and distant conversations are difficult to hear. With a hearing aid, the student can attend regular school.Mild41 55 dB As much as 50 percent of classroom conversations are missed. Limited vocabulary and speech difficulties may result.Moderate56 70 dBLoud conversations can be heard. Defective speech, language difficulties and limited vocabulary may result.Severe71 90 dBHearing is limited to a radius of one foot, enough to discriminate loud sounds. Defective speech and language and severe difficulty in hearing consonant sounds may result.Profound91 and aboveSounds and tones cannot be perceived. Vision becomes the primary sense of communication. Speech and language are likely to deteriorateIncidence and Prevalence(Philippines), estimated is 2% of the population has hearing impairment and the number may increase if children below school age and persons who lose hearing sensitivity due to old age are included.(United States), at least 1 in every 22 newly born infants has some degree of hearing impairment.At least 3 in 1000 infants have a severe or profound hearing impairment.US Department of Education claimed that children with hearing impairment constitute 1.3% of pupils provided with special education services and 11% of the total age population.ETIOLOGY OF HEARING IMPAIRMENTGENETIC AND HEREDITARY TYPES OF DEAFNESS occur in 1 out of 1000 live births. Causes are hereditary and chromosomals abnormalities.INFECTIONS such as maternal rubella, cytomegalovirus, hepatitis B virus, syphilis, mumps, and otitis media may occur during pregnancy or after birth.

These impulses are transmitted along the auditory nerve through the central nervous system pathways to the brain where the auditory experience is processed and understood.The semicircular canals in the inner ear control the sense of balance.

The more specific cause of conductive hearing loss are otitis media (middle ear infection), excessive earwax (impacted cerumen), and ostosclerosis (spongy boney growth around the stirrup which impedes its movements).Sensorineural hearing loss results from damage to the cochlea or the auditory nerve. Other causes are viral diseases, Rh incompatibility, hereditary factors, exposure to noise, aging and ototoxic medicationsFISTULAHole in or rupture of the oval or round window in the inner earMay leak perilymph (clear fluid) into the middle earCaused by head injuries, diving, barotraumas, violent sneezing, etc.Results in fluctuating and/or sudden sensorineural hearing lossCan be a complication of cholesteatomaDizziness can also be a symptomOTOTOXICITYCan be caused by a wide variety of strong antibiotics such as amino glycosides gentamicin, kanamycin and others as well as chemotherapeutic agents such as cisplatin, or loop direuticsCan result from exposure to various chemical agents in the environmentCharacterized by a progressive high-frequency sensorineural hearing loss following such exposureCHARACTERISTICS OF PERSONS WITH HEARING IMPAIRMENTSome of the observable behavioral and learning characteristics of a child with hearing impairment are as follows: Cups hand behind the ear, cocks ear/tilts head at an angle to catch soundsHas strained or blank facial expression when listening or talked toPays attention to vibration and vibrating objectsMoves closer to speaker, watches face especially the mouth and the lips of the speaker when talked toLess responsive to noise, voice, music and other sources of soundsUses more natural gestures, signs and movements to express selfShows marked imitativeness at work and playOften fails to respond to oral questionsOften asks for repetition of questions and statementsOften unable to follow oral directions and instructionsHas difficulty in associating concrete with abstract ideasHas poor general learning performanceAs mentioned earlier, the primary effect of a hearing impairment is on the development of speech and the acquisition of language and skills.The more severe the hearing loss is, the more difficult it is to acquire skills in listening, speech and communication, reading and writing.Speech is usually labored, unintelligible, unpleasant and difficult to understand.

Vocabulary is limited with problems in syntax.Speech sounds telegraphic and has poor rhythm.There are problems in articulation such as omission, addition, and substitution of letters and sounds or distortion of the words.Poor reading ability results to difficulties in learning the other school subjects

IDENTIFICATION AND ASSESSMENT OF CHILDREN WITH HEARING IMPAIRMENTAUDIOLOGICAL EVALUATIONDone by audiologist through the use of sophisticated instruments and techniquesTo determine frequencies of sounds that a particular person hearsAUDIOLOGY science of testing and evaluating hearing ability to detect and describe hearing impairmentsAUDIOMETER electronic device that generates sounds at different levels of intensity and frequencyPURE TONE AUDIOMETRY utilizes pure tone in air and bone conduction tests which yield quantitative as wells as qualitative description of a childs hearing loss.SPEECH AUDIOMETRY which uses speech instead of pure tones.Alternative audiometric techniques: sound field audioemetry, evoked response audiometry, impedance audiometry, play audiometry, operant conditioning audiometry and behavior observation audiometry.

INFORMAL HEARING TESTS (used in the Phils.)WHISPER TESTSit the child comfortably. Ask him or her to stick thetip of the forefinger in one ear.The tester sits behind the child where the uncoveredear is. After a deep breath, whisper some familiar words that contain high pitch and low pitch tones right behind the unblocked ear. The child must be able to repeat the words correctly

CONVERSATIONAL LIVE VOICE TESTKeeping the same position but facing the child, ask him or her to repeat words that contain high and low pitch consonants. Start with a whisper and increase the intensity up to 20 dB moving away from the child little by little. If the child hears at a distance of 3 to 6 meters, hearing is normal. If the child can repeat the words but speech is unclear, he or she might be hard of hearing

BALL PEN CLICK TEST Use a retractable ball pen and place it one inch away from the ear. While the other ear is blocked by a finger, press the button of the ball pen down and release it. Do it only once. The child indicates that he or she hears the click by either raising one hand or acknowledging it with a yes or a nod.

COGNITIVE ASSESSMENTDo not rely primarily on verbal abilities(US) The Hiskey Test of Learning Aptitude, the Wechsler Intelligence Scale for Children (WISC) and the Stanford Achievement Test (SAT) are widely used because of the nonverbal performance subtest

ASSESSMENT OF COMMUNICATION ABILITIESIncludes an analysis of the development of the form, content and use of language.Articulation, pitch, frequency, and quality of voice are examined

SOCIAL AND BEHAVIORAL ASSESSMENTHearing impairment brings about significant effects on social-emotional and personality development as a result of the restrictions in interactive experiences and communication activities with their age group.Linguistic difficulties oftentimes show in low self-concept and social-emotional maladjustment

EDUCATIONAL PLACEMENTIn the Phils., students with hearing impairment like other students with disabilities are mainstreamed in regular classes either on full-time or part-time basis.SUPPORT SERVICESCommunication accessibility is provided by sign language and oral interpreter inside and outside of the classrooms.Computer-aided instruction (CAI) reinforces the knowledge and skills learned in the different subject areasEducational Approaches Used When Working with Students with Hearing ImpairmentBILINGUAL-BICULTURALBasic Position: Considers American Sign Language (ASL) to be the natural language of the Deaf culture and urges recognition of ASL as the primary language choice with English considered a second language.Objective: To provide foundation in the use of ASL with its unique vocabulary and syntax rules; ESL instruction provided for English vocabulary and syntax rulesMethod of Communication: ASL (American Sign Language)

TOTAL COMMUNICATIONBasic Position: Support the belief that simultaneous use of multiple communication techniques enhances an individuals ability to communicate, comprehend and learn.Objective: To provide a multifaceted approach to communication to facilitate whichever method(s) works best for each individual.Method of Communication: Combination of sign language (accepts the use of any of the sign language systems), fingerspelling, and speechreading.AUDITORY-ORALBasic Position: Supports the belief that children with hearing impairment can develop listening/receptive language and oral language expression (English) skills; emphasizes use of residual hearing (the level of hearing an individual possesses), amplification (hearing aids, auditory training), and speech/language training.Objective: To facilitate the development of spoken (oral) English.Method of Communication: Spoken (oral) EnglishSuggestions for Teaching Students with Hearing Impairment in a Regular ClassPromote the acceptance of the student with hearing impairment in the regular class.Be sure that prescribed hearing aids and other amplification devices are used.Provide preferential seating.Increase visual information.Minimize classroom noise.Modify teaching procedures.Have realistic expectations.