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.

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)-

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

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

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.

Tinnitus Ringing in the ears Most tinnitus comes from damage to the microscopic endings of the hearing nerve in the inner ear.