بسم الله الرحمن الرحيم
Lecture Objectives
Deafness (Hearing loss) Hearing Aids Otosclerosis (Otospongiosis) Sudden Sensorineural Hearing Loss Drug ototoxicity Presbycusis (Senile hearing loss) Deafness and Noise Non-Organic Hearing Loss Tinnitus
Deafness (Hearing loss)
Hearing AidsA hearing aid is an electro-acoustic device used to amplify sounds. Design The basic components of any hearing aid are: Receiver ( microphone) Amplifier Sound transmitter (Ear phone) Power supply
Types of hearing aid
Behind-The-Ear (BTE) In-The-Ear and In-The-Canal Aids: Body-worn aids Bone conduction HA: sound is transmitted from a vibrator that fit on mastoid boneBone-anchored hearing aids (BAHA)
Cochlear implant: an electronic device that can provide useful hearing for persons who have severe SNHL who cannot benefit from HA. It is composed of: 1- External component: which consist an external speech processor and transmitter. 2- Internal component: is surgically implanted and comprises the receiver / stimulator package with an electrode array.OTOSCLEROSIS
Is hereditary localized disease of the otic capsule in which new spongy bone cause ankylosis of the foot plate of stapes leading to conductive deafness. Cochlear involvement with SNHL may also occur.
HISTOPATHOLOGY
Resorption of bone by osteocytes Formation of new vascular spongy boneAREAS OF PREDILECTION
Fissula ante fenestram (80% to 90%)COCHLEAR INVOLVEMENT
AETIOLOGYHereditary factors: (50%) / autosomal dominant pattern with incomplete penetration. Racial distribution: white races (Caucasian) > coloured. Age: 15-45 years of age. Sex: females: male= 2:1. Pregnancy: may accelerate the condition but NEVER cause it.
CLINICAL PRESENTATION
Hearing loss of gradual onset at 15 - 45 years Slowly progressive course 80% are bilateral Accelerates with pregnancy (30-40%) Tinnitus (75%) Paracusis Willisii Change of the speech patternPHYSICAL EXAMINATION
Normal tympanic membrane Schwartze sign (Flamingo flush) * seen through the membrane due to hyperaemia of the promontory * indicates rapid progression of the disease. Tuning fork testsPURE TONE AUDIOMETRY
Conducive deafness. Carhart’s notch: is an increase in bone conduction threshold with a peak at 2,000 Hz. Explanation is not known Reverses following successful surgery In advanced cases there may be SNHL
Treatment
Hearing aids Medical: sodium fluoride?! Surgical: stapedectomy which is total or partial removal of the foot plate of the stapes and replacement by prosthesis. Complication: perilymph fistula which is characterized by sudden SNHL and vertigo. It is liable to occur after sudden changes of pressure, so the patient should avoid diving and only fly in pressurized aircrafts.Sudden Sensorineural Hearing Loss
Aetiology Idiopathic: in 2/3 of cases Vascular: spasm, thrombosis or haemorrhage of the internal auditory artery. Viral infection: mumps, measles, rubella or Herpes zoster. Head injury with temporal bone fracture, blast injury, and ear surgery as stapedectomy. Tumors: acoustic neuroma.Clinical Picture
Hearing Loss Tinnitus: 80% --a good prognostic sign and means that hair cell still functioning. Vertigo: is common in those with vascular aetiology and caries a bad prognosis. Examination The TM is usual normal. Tuning fork test PTA: hearing loss in high frequency.Treatment
Bed rest and sedation.Steroids in tapering dose.Vasodilators: Betahistine (Betaserc).Low molecular weight dextranPrognosisIn 1/3 quick recovery. If there is no recovery within 3 weeks it is unlikely to occur spontaneously. In 1/3 partial recovery In 1/3 have none. Unfavorable prognostic features are severe HL and vertigoDrug ototoxicity
Damage to the cochlear and/or vestibular part of the inner ear by certain drugs.Ototoxic drugs include:AminoglycosidesLoop diureticsSalicylates.Quinine.Antiepileptics; phenytoin.B-blockers.Cytotoxic; cisplatin.Synergistic effect….The dangers are especially great if excretion is impaired as in renal failure.Presbycusis (Senile hearing loss)
A symmetrical, progressive, bilateral SNHL age > 65 years no underlying cause. The degenerative changes occur as a result of aging process and vascular insufficiency Treatment Lip reading Hearing aidsDeafness and Noise
Excessive sound stimulation two types of SNHLAcoustic trauma…very brief exposure…Noise-induced hearing loss..excess of 85dB for 8 hours/dayPTATreatmentPreventive:Therapeutic:Rest and avoidance of future trauma.Hearing aids
Non-Organic Hearing Loss
Psychogenic (hysterical) Malingering. Diagnosis History Examination Audiometry; repeated audiograms give different results on each occasion.Fracture base of the skul
The longitudinal is more common than transverse. Deafness Tinnitus and Vertigo Tympanic membrane. Facial nerve palsy is seen more often in transverse fracture X-ray and CT scan of the base of skullTreatment:Bleeding from the ear, with or without facial nerve palsy, after head injury means fracture base of skull until prove other wise.Never syringe the ear.No instrumentation of the ear.No caloric test.Systemic antibiotic…Facial nerve paralysis...