1.3.2 Conduction vs. Sensoneural Deafnness

Causes and Corrections

• Conductive hearing problems are those that disrupt the conduction of sound through the outer and middle ear.

Conductive Hearing Loss

• Affects hearing before the sound reaches the cochlea and the nerve receptors of the inner ear.

The Good News

• Conduction deafness is often temporary or curable

Causes of Conduction Deafness

• Otitis Media• Middle ear infection• Chronic suppurative otitis media –

1.Peferation of the tympanic membrane

2. Bacterial infection

l

“Glue Ear” Collection of fluid in the middle ear - (otitis media with effusion)

• Thick, sticky fluid collects behind the eardrum. • The fluid blocks the middle part of the ear and

can cause impaired hearing.• It usually affects children.

Interventions for “Glue Ear”

• Antibiotics• Ear Tubes (grommet)

Cerumen

• Ear Wax

Blockage of the outer ear, usually by wax.

Otosclerosis

• Ossicles of the middle ear harden and become less able to vibrate.

Otosclerosis

• Approximately one-third of all persons with impaired hearing have this condition.

• Hereditary• Damage to the ossicles, e.g. by serious infection or

head injury. • Perforated (pierced) eardrum, which can be caused

by an untreated ear infection (chronic suppurative otitis media), head injury or a blow to the ear, or from poking something in your ear.

Interventions

• Hearing aids -usually effective for conductive hearing loss.

http://www.nlm.nih.gov/medlineplus/ency/imagepages/8685.htm

Interventions

• Stapedectomy - top part of the stapes is removed. A laser beam is used to create a small hole in the footplate and a metal tube is inserted. A wire attached to the tube connects to the incus and transmits vibrations to the inner ear.

Sensorineural deafness

• Sensorineural deafness is decreased hearing or hearing loss that occurs from damage to the inner ear, the auditory nerve, or the brain.

• Sensorineural hearing loss is most often due to a loss of hair cells (sensory receptors in the inner ear).

• Sensorineural deafness can be present at birth (congenital), or it can develop later in life

• (SNHL) accounts for about 90% of all hearing loss

• Found in 23% of population older than 65 years of age

Causes of Sensorineural Deafness

• Presbycusis - hearing loss that gradually occurs in most individuals as they grow older

Presbycusis

• Aging

• Loud noises (acoustic trauma)-

http://www.healthpractical.com/tag/great-stressors

Duration

• The period of time the sound continues to exist.

• “Exposure to sound levels of 85 decibels, the equivalent of a lawn mower or food blender, may cause permanent hearing loss if endured for 8 hours per day for a prolonged period”

Healthy Cochlea

The cilia ( sensory hairs) appear normal

Damaged Cochlea

Loss of cilia as a result of Noise

Occupational Risk

• Some jobs carry a high risk for hearing loss, such as:

• Airline ground maintenance • Construction • Farming • Jobs involving loud music or machinery

Interventions:

• Hearing aid • Hearing aids will not restore normal hearing

or eliminate background noise. • Amplfies sound• Adjusting to a hearing aid is a gradual process

that involves learning to listen in a variety of environments and becoming accustomed to hearing different sounds.

Prevention

http://www.rainbowsafety.co.uk/warning-noise-levels--wear-ear-protection-sign-map-43-1438

Cochlear Implants

• Auditory understanding of the environment and helps in understanding speech.

• Does not reinstate or generate normal hearing.

• Compensates for damaged or non-working parts of the inner ear.

• Surgically implanted under the skin behind the ear, this device is made of four basic parts:

• microphone picks up sound from the environment

• speech processor translates the sounds picked up by the microphone into signals

• transmitter and receiver/stimulator receive these signals and convert them into electric impulses

• electrodes send these impulses to the brain.

Cholesteatoma

• Benign skin growth in the middle ear, causing deafness and vertigo

Intervention

• surgical removal of the cyst.

Acoustic neuroma

• A benign (non-cancerous) tumor affecting the auditory nerve

http://med.mui.ac.ir/slide/clinical/ent/AcousticNeuroma.jpg

Intervention

• Radiosurgery The use of ionizing radiation, either from an external source such as an x-ray machine or from an implant, to destroy cancerous or other diseased tissue.

http://www.health.wvu.edu/services/neurosurgery/gamma-knife/images/header.jpg

Tinnitus

• Ringing in the ears • Most tinnitus comes from damage to the

microscopic endings of the hearing nerve in the inner ear.