Hearing loss and deafness

Hearing loss, or hearing impairment happens when one or more parts of the ear or ears are not functioning   Or Hearing loss, hearing impairment, or deafness, is a partial or total inability to hear

Etiological factors Aging (presbycusis) N0ise exposure Disease Injury to the ear Chinldren – ear infections, congenital defects At age 50, one of every eight persons is hearing impaired.

External ear Impacted cerumen Foreign bodies External otitis Middle ear Otitis media Serous otitis otosclerosis Inner ear Menieres disease Noise exposure Presbycusis ototoxicity

Types Conductive hearing loss Sensorineural hearing loss Mixed hearing loss Central and functional hearing loss Noise induced hearing loss

Conductive hearing loss Conductive hearing loss results form interference with the conduction of sound impulses through the external auditory canal, tympanic membrane or the ossicles of the middle ear. It can caused by anything that blocks the external ear such as cerumen, infection or a foreign body. It may also be caused by thickening, retraction, scarring or perforation of the tympanic membrane or any pathophysiologic change in the middle ear (tumours, previous surgeries, otosclerosis)

Sensorineural hearing loss It results form disease or trauma to the inner ear, neural structures, or nerve pathways leading to the brain stem Diseases that effect may be systemic or local infections or may be drug induced. Systemic diseases – diabetes mellitus, arteriosclerosis and infectious disease such as measles, mumps and meningitis Local diseases - neuromas of the eighth cranial nerve, otospongiosis, trauma to the head or ear, degeneration of the organ of corti

Mixed hearing loss It is caused by a combination of conductive and sensorineural losses

Central and functional hearing loss Central auditory dysfunction- it is a rare form of sensorineural hearing loss in which hearing ability remains intact but the patient is deaf because the central nervous system is unable to interpret normal auditory stimuli. Central deafness can results from tumors or stroke Functional hearing loss – by an emotional or a psychologic factor. The patient does not seem to hear or respond to hearing tests, but no organic cause can be identified.

Classification of hearing loss (based on severity) The decibel (dB)is a measure of the loudness or intensity of sound. A hearing loss of 15 to 50 dB is a mild to moderate loss (impaired hearing) A loss of 50 to 80 dB is severe hearing loss A loss of more than 80 dB in both ears is a profound hearing loss and referred as DEAF.

Noise induced hearing loss Hearing loss due to exposure to noise accounts hearing impairment among people between 35 to 65 years. If hearing loss results from a single exposure to a sudden loud noise or blast is referred as ACOUSTIC TRAUMA. Hearing loss occurs over time from repeated injury from noise is referred as NOISE – INDUCED HEARING LOSS.

OSHA (OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION) has establish acceptable noise levels in work environment. Ordinary speech is 60 dB and in heavy traffic it is 80 Db Exposure to 85 to 90 dB for months can cause cochlear damage. Based on OSHA regulations, the work environment exceeding noise above designated limits should wear EAR PROCTECTION DEVICES.

PRESBYCUSIS Hearing loss associated with aging that becomes more common after 50 Changes in the delicate labyrinth structures over decades cause hearing loss

Clinical features Asking others to speak up Straining to hear Cupping hand around ear Answering questions inappropriately Not responding when not looking at the speaker Showing irritability with others Increasing sensitivity to slight increases in noise level. Family and friends who get tired of repeating or talking loudly are often first to notice hearing loss

Tinnitus Ringing noise Tinnitus accompanies most sensorineural hearing losses and is often a warning of impending or worseing hearing loss Persistent tinnitus is very annoying and the only cure is correct the underlying condition.

Deafness is often called the UNSEEN HANDICAP. Patient refuses to admit or unaware of impaired hearing Withdrawal, suspicion, loss of self esteem and insecurity are commonly associated with advancing hearing loss

Diagnostic features History collection from the family members or friends Physical examination All diagnostic measures for testing ear function should done to rule out the exact cause of the hearing loss and also to treat the underlying disorders CT scan, MRI, Blood test and cultures, audiometry, tympanometry, electronystagmograpy, arteriograpy.

Management Health promotion Use of ear protectors while working in noisy conditions Treating the ear disorders as early as possible Avoiding drinking and driving Avoid alcoholism Organize health teaching programs in schools, communities and factories for preventing the hearing impairment

Immunizations Various viruses can cause deafness as a result of fetal damage and malformations affecting the ear Mumps, measles and rubella immunization should be provided Infection during the first 8 week of pregnancy with rubella can leads to sensorineural deafness

Ototoxic substances Chemicals used in industry (toluene, carbon disulfide and mercury) may damage the inner ear Drugs – antibiotics, salicylates, diuretics and antineoplastic drugs Symptoms of ototoxicity are tinnitus, impaired hearing and vestibular dysfunction If symptoms develop immediate withdrawal of the drug may prevent further damage.

Assistive devices and techniques Hearing aids – can assist individuals with hearing impairments. Hearing aids should be fitted by an audiologist or a speech and hearing specialist after a through physical examination and hearing tests. Hearing aids amplify sound in a controlled manner.

Hearing aids consist of A microphone to receive sound waves from the air and change sounds into electrical signals An amplifier to increase the strength of the electrical signals A battery to provide the electrical energy to needed to operate the hearing aid A receiver (loudspeaker) to change the electrical signals back into sound waves.

Types of hearing aids Five basic types MICRO CIC (completely in the canal) hearing aid ITC (in the canal ) hearing aid HS (half shell) hearing aid ITE (in the ear) hearing aid BTE (behind the ear)hearing aid

HALF SHELL IN THE EAR

Adjusting with the hearing aids The nurse should explain the uses of it in detail The patient must adjust the voices and household sounds Experiment by increasing and decreasing the volume If the patient is adjusted to the background noise, the patient is ready to go for a small party where several peoples talk simultaneously After adapting to controlled situations, the patient can encounter environments such as shopping mall etc

Care of a hearing aid When the hearing aid is not being worn, it should be keep in a dry, cool area The battery should be disconnected or removed Battery life is 1 -4 week (different based on the types) Wash the ear mold frequently with mild soap and water Toothpicks and pipe cleaners may be used to clear a clogged ear tip. Turn the hearing aid off when not in use Keep an extra battery Do not wear ear aid if an ear infection is present

If the Hearing aid fails to work - Check the on-off switch Inspect the ear mold for cleanliness Examine the battery for correct insertion Change the battery Check for any break in the aid

Implantable hearing devices They are of two types Cochlear implants Bone conduction devices

Cochlear implant devices It is used as a hearing device for people with severe to profound deafness who get little or no benefit from a hearing aid The implant is an electronic hearing device that stimulates nerves within the inner ear The system consists of a surgically implanted induction coil beneath the skin behind the ear and an electrode wire placed in the cochlea The implanted parts interface with an externally worn speech processor The device does not allow the person to hear speech but creates an awareness of environmental sounds such as doorbells or telephones etc.

Bone conduction devices It transmit sound through the skull to the inner ear Surgically implanted titanium screw implanted under the skin into the skull behind the ear Once it heals, it is loaded with a vibrating hearing aid.

AURAL REHABILITATION If hearing loss is irreversible and not surgically correctable, AURAL REHABILITATION is recommended It includes auditory training, speech reading, speech training, sign language to maximize the communication of a hearing impaired person

Speech reading It is also called as lip reading – helps in increasing communication skills. The patient is able to use visual cues associated with the speech, such as gestures and facial expression to clarify the spoken message In speech reading several words will look like alike (for ex: Oman, women ) The nurse should help the patient by using and teaching verbal and nonverbal communication techniques.

Nonverbal aids Draw attention with hand movements Have speakers face in good light Avoid covering mouth or face with hands Avoid chewing, eating, smoking while talking Maintain eye contact Avoid distracting environments Avoid careless expression Use touch Move close to better ear

Verbal aids Speak normally and slowly Do not over exaggerate facial expressions Use simple sentences Write name or difficult words Avoid shouting

Sign language Sign language is used as a form of communication for deaf people It is a visual – spatial language that involves gestures and facial features such as eyebrow motion and lip mouth movements. Sign languages is not universal.

Bluetooth® and Wireless Accessories Updates in hearing aids Allows users to connect hearing instruments directly to peripheral accessories such as: Cellular and home phone Television and music players Signaling devices like door bells and fire alarms With this technology, hearing instruments are becoming more like personal communication devices.