Hearing Impairment

SCREENING AND IDENTIFICATION

A Hearing screening is a quick test to see how well an individual can hear different sounds. Identification of hearing loss has never been easier than it is now. Patient populations of all ages and developmental levels can be tested subjectively or objectively to provide information about the function of their auditory system. Specialized testing for difficult to test populations has become more widely accepted and is able to be performed safely and easily. Some or all of the following testing may be performed as part of a battery of tests to assess your auditory system.

• Pure Tone Audiometry: Utilizing age appropriate techniques
• Speech Audiometry: Speech Detection Threshold, Speech Reception Threshold, Word Recognition Score
• Immittance Measures: Tympanometry, Acoustic Reflexes, Acoustic Reflex Decay
• Hearing in Noise Testing

For new born babies and infants screening is done which is simple and painless. The two common methods are:

• Otoacoustic Emissions– This is used to check the response of the inner ear.
• Auditory Brain-stem Response (ABR) Testing– Used to check the brain responses to sound.

Pure Tone Audiometry: Pure tone test is the most common screening for older children and adults. This is done by a device called Pure Tone Audiometer.

• It is an electronic device used for creating pure tone audio gram.
• It consists of an audio-oscillator which generates pure tone sounds of different frequencies.
• This audiometer is connected to standard and specified bone connection vibrator or earphones through which sound is presented to Subjects ear.
• PTA is a subjective, behavioral measurement of a hearing threshold. It relays on the responses of patient to pure tone stimuli.

IDENTIFYING THE CHILD WITH HEARING IMPAIRMENT IN THE CLASS

It is important to identify the hearing impairment as early as possible; otherwise the child will also miss out on important educational experiences. Sometimes hearing impairment can go unidentified partly because it is not immediately visible. A hearing impairment could be so mild that it may it may have gone unnoticed for many years.

On the other hand, a hearing impairment may develop over time.  The student is often the last one to recognize or report a loss in hearing unless it has deteriorated significantly. The adverse effect of the hearing impairment can create challenges in personal, academic and social nature for the student and interfere with reaching full potential.

A possible hearing loss is more difficult to identify in older children, whose speech skills are already developed. Nevertheless, Teachers need to be aware of the indicators that signal the possibility that a student has an undiagnosed hearing loss.

• Not responding when addressed.
• Constant requests to repeat what was said. Asking for information to be repeated frequently.
• Turning head to position ear in the direction of the speaker.
• Favoring one ear over another, Student moves one ear forward when listening, or he complains that he can only hear out of his “good ear”
• Child cannot localize sound (tell where the sound is coming from)
• Using a loud voice when speaking. Child starts to speak more loudly than previously.
• Mispronouncing words such as misarticulation of certain speech sounds or omitting certain consonant sounds.
• Difficulty with following directions or instructions.
• Intently watching faces during conversation. If the student looks intensely when you speak to them, as if concentrating, they may be depending more on visual cues for interpreting speech.
• Appearing to be inattentive, restless, tired or daydreaming
• Preferring to be by themselves (i.e., playing alone rather than with a group, or withdrawing from social situations)
• Trouble understanding speech, especially in noisy environments.
• Problems in hearing environmental sounds (i.e., doorbell, people calling and/or a student talking from behind)
• Loss of interest in class. Worsening grades, especially those involving in-class lectures, in which the child cannot listen the information being taught
• Increasingly withdrawn behavior.

CHARACTERISTICS OF HI

• Complains of ear discharge, frequent ear aches and pain around the ear.
• Delays in the development of speech and language are classic symptoms of hearing loss and deafness in children.
• Children with poor hearing might be unable to communicate because they cannot understand or imitate spoken language
• Child seems to hear fine some of the time and then not respond at other times
• Child says that they didn’t hear you. This may seem obvious, but many parents assume that their children are not paying attention when in fact there may be an unidentified hearing loss.
• Failure to hear his/her name called, Not responding when addresses.
• Listening to television or radio at a high volume. Difficulty in hearing people on the phone.
• The perception that others are mumbling as they cannot hear them.
• Child has difficulty in identifying or to locate certain sounds.
• Communication characteristics: Child may not be able to speak properly. Vocabulary may contain many words that are often missing endings.
• Social characteristics: The child is Curious and lacks Self-confidence. Often times children with hearing loss avoid social situations, sports, parties and family events. These get-together can cause a feeling of being overwhelmed by his or her inability to communicate and understand.
• Emotional characteristics: Shows Impulsive behavior i.e problems with emotional or behavioral Self-control. Sometimes shows Hyperactivity.

CLASSIFICATION OF HEARING IMPAIRMENT

BASED ON TYPE OF HEARING LOSS

1. Sensorineural Hearing Loss: For the majority of individuals, a sensorineural hearing loss is caused by a problem with the structure or function of the inner ear (sensory) or the auditory nerve (neural). Because it is often difficult to determine the exact location of the problem, this type of hearing loss is referred to as a sensorineural hearing loss.

Typically, there is no medical or surgical treatment that will correct or even reduce the severity of the hearing loss. Fortunately, hearing aids or cochlear implants provide good benefit to individuals with sensorineural hearing loss.

Common causes of sensorineural hearing loss include:

• Congenital (present at birth) factors
• Hereditary or genetic factors
• Exposure to medications that are toxic to hearing
• Viral or bacterial disease
• Excessive exposure to loud noise
• Aging (presbycusis)

2. Conductive Hearing Loss

A problem in the outer or middle ear will cause a hearing loss known as a conductive hearing loss. Causes of conductive hearing loss include any condition that prevents the sound from reaching the eardrum, that prevents the eardrum from vibrating effectively and/or that prevents the middle ear bones from vibrating effectively. With all of these conditions, the inner ear and the hearing nerve may be completely normal; however, they are not receiving sounds properly because transmission of sounds through the outer and/or middle ear is reduced. Generally, conditions that cause conductive hearing loss are medically or surgically treatable, and there is potential for hearing to improve.

Common ear problems that can cause conductive hearing loss include:

• Ear canal blocked with wax
• Infection in the ear canal
• Malformed or absent ear canal at birth (congenital atresia)
• Hole in the eardrum
• Fluid in the middle ear (otitis media)
• Infection of the bony tissue around the middle ear (mastoiditis)
• Stiffness of the middle ear bones
• Discontinuity or trauma to the middle ear bones

3. Mixed Hearing Loss

A mixed hearing loss can exist in which there are problem with the outer or middle ear, as well as the inner ear. This can happen when a person has more than one medical problem at the same time. In these cases, it may be possible that the conductive hearing loss can be corrected, while the sensorineural loss remains permanent.

Many children with sensorineural hearing loss can experience additional conductive hearing loss caused by middle ear fluid. This conductive loss overlays the existing sensorineural hearing loss and increases the severity of the hearing loss. It is very important to monitor your child for ear problems, or a noticeable change in hearing, and to seek medical assistance if concerns arise.

BASED ON DEGREE OF HEARING LOSS

While hearing loss type is important the affect on a patient’s life is often determined by the degree of hearing loss. In the past, audiologists and physicians may have defined hearing loss through a percentage (i.e. 20% loss, 50% loss etc). However, due to the fact that most hearing losses are not flat the degree of loss may vary at different pitches. It has become widely accepted practice to describe the hearing loss based on a classification system.

1. Mild hearing loss: Speech may be hearing in quiet but becomes difficult to understand when there is background noise in the environment or when speech is at a distance.
2. Moderate hearing loss: Speech can be heard at a normal level only in quiet and in very close proximity.
3. Moderately- severe hearing loss: Even in a quiet environment speech must be loud in order to be heard, understanding may be impaired even with this louder signal.
4. Severe hearing loss: Speech is very difficult to understand in all situations.
5. Profound hearing loss: Communication can be very difficult even with hearing aids.

BASED ON THE NATURE OF ONSET

1. Gradual Hearing loss: Progresses at a slow rate. Ex- Presbycusis
2. Sudden hearing loss: Instant loss or that progresses every 24 to 48 hours.

BASED ON THE ACQUISITION OF HEARING LOSS

1. Congenital hearing loss: Present at the time of birth
2. Acquired hearing loss: Onset subsequent to birth. It of two types
3. Profoundly Pre-lingual deafness:- Individuals born with insufficient hearing to acquire normal speech or who lost their hearing prior to the age at which speech is acquires.
4. Post Lingual deafness:- It develops after the acquisition of speech and language, usually after 6 years of life.