Hearing loss/Deafness
Deafness is partial or complete hearing loss.
Hearing loss is "hard to hearing". Only able to hear some of speech and sounds around them.
Classification of Hearing Loss
Hearing impairment measures according to loudness (dB).
According to "WHO" degree of hearing loss;
Degree of Hearing Loss Hearing Loss Range (dB)
Mild 25 - 40dB
Moderate 41- 55dB
Moderately severe 56-70dB
Severe 71-90dB
Profound 91dB or greater
Types of Hearing Loss
1. Conductive hearing loss
2. Sensorineural hearing loss
3. Mixed hearing loss
1. Conductive hearing loss
Conductive hearing impairment resulting from dysfunction of outer ear, tympanic membrane or nones of middle ear.
Conductive hearing loss occurs when sounds can't get through the outer ear and middle ear due to malformation of outer ear, ear canal, or middle ear structure.
Etiology
External Ear
1. Impacted cerumen (earwax)
2. Otitis externa
3. Foreign body in external auditory canal
Middle Ear
1. Acute otitis media
2. Tympanic membrane perforation
3. Ossicles deformity
4. Cholesteatoma
5. Otosclerosis
Inner Ear
1. Labyrinthitis
2. Disturb Eustachian tube function
2. Sensorineural hearing loss
Sensorineural hearing loss result from dysfunction in inner ear, cochlea, vestibulocochlear nerve (CN Vlll), labyrinth, inner ear organs.
Cochlea where sound vibration converted into neural signls.
Sensorineural hearing loss can be mild, moderate, severe, profound.
Sensorineural hearing loss cause central hearing loss.
Etiology
1. Abnormalities in hair cells of organ of Corti in cochlea
2. Vestibulocochlear nerve (CN VIll) impairment
3. Auditory portion of brain impairment
4. Meniere's disease
5. Labyrinthitis
6. Otosclerosis
7. Congenital abnormality
8. Acoustic neuroma
9. Trauma
10. Infection
11. Presbycusis; age related hearing loss
12. Exposure to ototoxic Drugs/ chemical
13. Fetal alcohol syndrome
3. Mixed Hearing Loss
Hearing loss result in both conductive hearing loss or sensorineural hearing loss.
Clinical Manifestations
1. Vertigo
2. Tinnitus
3. Postural imbalance
4. Difficulty in understanding words
5. Slow, progressive hearing loss
6. Poor concentration
7. Poor concentration
8. Headache
Management
1. Removal of impacted wax
2. Hearing aids
3. Aural rehabilitation therapy
Surgical Management
Restore conductive hearing loss;
1. Myringotomy
2. Stapedectomy
Assisted hearing in profound deafness;
1. Cochlear implant
2. Middle ear implant
3. Opening eustachian tube
4. Temporal bone stimulators; stimulate cochlea
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