Chapter 14

Genetic/Environmental Cause

-Genetic and environmental factors that can result in hearing loss are numerous, although in many cases the specific cause is unknown. -Autosomal dominant hearing loss -Autosomal recessive hearing loss

Severity

-The severity of hearing loss ranges from mild to profound and is typically defined using decibels (dB): - -10 dB to 15 dB: Normal hearing - 16-25 dB: Slight loss - 26-40 dB: Mild loss - 41-55 dB: Moderate loss - 56-70 dB: Moderately severe loss - 71-90 dB: Severe loss - 7 91 dB: Profound loss

Air Conduction

-Tone is played via headphones or speakers -Provides information about entire ear system

Type of Loss

-identifies the auditory structures that are affected. -Conductive hearing loss -Sensorineural hearing loss -Mixed hearing loss

Prelingual

Loss occurring before language is acquired

Acquired

Occurs sometime after birth

Air-bone Gap

Difference between air conduction threshold and bone conduction threshold

Autosomal recessive hearing loss

both parents carry a recessive trait for hearing loss, but neither of them are hearing impaired

Incidence/Prevalence

-3:1,000 babies in U.S. born with HL -9:1,000 U.S. Kindergarteners have HL -360 million people in the world have HL(28.6 million Americans) -Prevalence increases with age

Causes and Risk Factors for CHL- Adult

-A common cause is cerumen blockage, particularly due to the use of cotton swabs. -Foreign objects inappropriately put into the ear canals or inflammation ofthe ear canal can also block the transmission of sound, causing conductive hearing loss. -Adults also experience otitis media, although it occurs far less frequently than it does with children because of structural changes in the ear mechanism (e.g., the lengthening and curving of the eustachian tube) and an improved immune system, which allows adults to resist chronic infections.

Comprehensive Audiological Evaluation

-A comprehensive audiological evaluation assess the type and degree of hearing loss, speech discrimination and auditory perception abilities in quiet and noisy conditions, and any other concerns. -Case history -Interview and observation -Otoscopic examination -Audiometry

Causes and Risk Factors for CHL- Child

-Children frequently experience conductive hearing loss, which in many cases can be reversed. -Because it is unwise to clean the ear canal with cotton swabs and because many children have narrow ear canals, wax buildup can occur frequently and block sound transmission. -Otitis media is most common cause

Auditory Brainstem Response

-Electrical signals are passed from the cochlea to the cortex -Latency: amount of time between when a sound is presented and when the brainstem responds -Measured via electrodes on the scalp -Useful for infants or people who are difficult to test

Classification

-Hearing loss in children and adolescents is typically classified according to its etiology, its manifestation and impact, and its severity -Genetic or Environmental Cause -Age of Onset -Type of Loss

Manifestation

-Hearing loss is also classified according to the aspects of audition that are impacted- that is how the disorder is manifested. Some children with hearing loss experience loss of hearing acuity, referring to the precision of hearing at different levels of loudness -More problematic than a loss in acuity is a decrease in auditory comprehension of spoken language and speech perception, which can accompany hearing loss.

Tympanometry

-Immittance -A probe is placed in EAC that emits air pressure and sound to measure immittance -Can indicate: Perforated TM, Middle ear fluid, and Stiff/dysfunctioning ossicular chain

Causes and Risk Factors of SHL- Child

-Most often, it is present at birth as a congenital hearing loss. -The following present the greatest risk: Serious illness, drug use, or other problems of the mother during pregnancy (In utero infections, including CMV, herpes, toxoplasmosis, syphilis, and rubella) -Many others -Cause of deafness (in known caused-cases): Genetics and heredity, Pregnancy related, and Postbirth disease or injury

Conductive HL

-Outer and middle ear damage ; nerve intact -When sound is not conducted efficiently through the outer or middle ear, the result is an attenuating, or reduction, of the sound heard. -Children who have a it, whether it is temporary or persistent, experience this attenuation of loudness. -it results in a sense of fullness or plugged ears and generally causes a slight to moderate loss of hearing in one or both ears. -It is typically amenable to medical or surgical intervention and therefore is often a temporary loss

Otoacoustic Emissions Test

-The inner ear produces faint sounds spontaneously -Present in people with normal hearing -Absent in all people with HL -These sounds can be measured to determine functioning of hair cells in cochlea -Because they are absent in all people with HL, they do not indicate degree of HL

Causes and Risk Factors of SHL- Adult

-There are many causes of sensorineural hearing loss, the most frequent being presbycusis and noise exposure. -Presbycusis is a degeneration of the inner ear and other auditory structures as a result of the normal aging process. It is a progressive loss that begins in early adulthood but may not be noticeable until the fifth or sixth decade of life. -Other influencing factors include -The intensity of the noise -The length of exposure -The use of hearing protection -The recovery time between exposures -Other forms of damage to the cochlea -Ototoxicity -Labyrinthitis -Meniere's Disease -Acoustic Neuromas

Bone Conduction

-Vibration on skull behind hear -Provides information about the cochlear system -Bypasses outer and middle ear

Auditory Masking

-When there is not symmetric hearing loss, sound presented in one ear can cross into the other ear -Common during bone conduction -refers to presenting noise to the ear not being tested -Allows more accurate test of the ear with greater hearing loss

Recognition

-Whether a person can discriminate one sound from others -Important for processing speech

Detection

-Whether a person can hear a sound -Not necessarily able to recognize the sound

Mixed HL

-both conductive AND sensorineural exist -typically includes a permanent reduction of sound as well as additional temporary loss of hearing from the conductive component. -Such as otitis media or buildup of cerumen in addition to SNHL

Sensorineural HL

-damage to hair cells, cochlea or auditory nerve -the most common type of hearing loss; it results from damage to the cochlea or the auditory nerve that travels from the cochlea to the brain. -Even though sensorineural disorders are thought of as a decrease in overall loudness, they are also associated with a decrease in speech perception and a decreased ability to distinguish speech from background noise.

Screening

-generally falls into two categories, depending on the child's age. -Infant hearing screenings, also called newborn hearing screenings, are completed at birth an involve specialized testing that is typically completed before a newborn leaves the hospital. -Conventional hearing screening - audiometer, headphones

Hearing Loss Definition

-is highly variable. -Location of damage to the hearing structures -Because we have two ears, hearing loss varies in whether it affects one or both ears. -The extent to which hearing acuity is impacted

Age of Onset

-is typically differentiated into developmental or acquired. -Developmental -Acquired -Prelingual -Postlingual -Presbycusis

Postlingual

Loss occurring after language is acquired

Audiometry

PURE Tone testing in which you obtain a behavioral response with regard to hearing acuity. Person raises hand or places a token in a bucket (for pediatric patients) when tone of different frequencies and intensities are presented

Acoustic Neuromas

Tumors can be hard to identify and are usually noticed first by a decrease in hearing in one ear, followed by a feeling of fullness or pressure

Postlingual hearing loss

after language onset

Prelingual hearing loss

before language onset

Otoscopic examination

checking out the ear! (looking at it)

Congenial hearing loss

hereditary

Autosomal dominant hearing loss

one parent has hearing loss and is carrier of a dominant gene

Otitis Media

viral or bacterial infection of middle ear.

Meniere's Disease

A long term disorder caused by an overproduction or underabsorption of endolymph, a fluid that circulates in the inner ear, resulting in a progressive hearing loss

Labyrinthitis

A short-term infection that is treated medically

Presbycusis

Age-related hearing loss

Ototoxicity

Another common cause of inner-ear damage and sensorineural hearing loss.

Audiometer

Electronic device used to test hearing

Developmental

Present at birth

Immittance

Ratio of sound that passes through the tympanic membrane vs. sound that is reflected