The Nucleus Hybrid L24 Cochlear Implant System for sensorineural
hearing loss
Presentation By :Indu Nath. SM Pharm part IIPharmacy Practice
Contents
Introduction Physiology of hearing Hearing loss
Sensorineural hearing loss
The Nucleus Hybrid L24
Cochlear Implant System
Advantage
Limitation Conclusion References
Introduction
The ear is the organ of hearing and balancing.
It is supplied by the 8th cranial nerve, i.e. the cochlear part of the vestibulocochlear nerve which is stimulated by vibrations caused by the sound waves.
The ear has three divisions, namely external ear, middle ear and inner ear.
Physiology of hearing
Hearing loss
Hearing loss ,hearing impairment, or deafness, is a partial or total inability to hear.10 % of adults has some hearing loss and one third of individuals over the age of 65 have a hearing loss of sufficient magnitude and require hearing aid.
Results from disorder of the auricle, external auditory canal, middle ear, inner ear, or central auditory pathway.
Lesions in the auricle, external auditory canal, or middle ear cause conductive hearing losses.
Lesions in the inner ear or eighth nerve cause sensorineural hearing losses.
Types of hearing loss
Hearing loss
Conductive
Sensorineural Mixed
Hearing impairments are categorized by their type, severity, ad the onset of age.
Conductive hearing loss: a conductive hearing impairment occurs when the sound is not reaching the inner ear and the cochlea.
External ear canal malformation, dysfunction of the ear drum or malfunction of the bones of the middle ear.
Other reasons include trauma and infections. Mixed hearing loss: conductive and sensorineural
hearing loss in combination is termed mixed hearing loss.
Otosclerosis involving the ossicles and cochlea, head trauma, chronic otitis media, middle ear tumors and inner ear malformations.
Sensorineural hearing loss
Sensorineural hearing loss is the most common form of
hearing loss and occurs when there is a lesion in the inner ear or eighth cranial nerve
(vestibulocochlear nerve) .
It may be caused by aging, heredity, exposure to loud noise, ototoxic drugs, viral infections and certain other
illnesses .
Sensorineural hearing loss can be mild, moderate, or severe,
including total deafness.
Sensorineural hearing loss can be treated with hearing aids
and also with cochlear implants.
Sensorineural hearing loss
• Epidemiology:
Gender: Males affected by hearing loss at an age earlier age than females Age : Older people are affected. Onset of age is over 40 years
• Causes : Presbycusis (related to aging) Noise induced hearing loss Cranial nerve 8 diseaseo Meniere's diseaseo Acoustic neuroma Viral Micro vascular diseaseo Diabetes mellituso Hyperlipidemia
Ototoxic medications Endocrine disease
o Hypothyroidism Autoimmune hearing loss Congenital deafness Traumao Temporal bone fracture involving Cochlea or vestibule• Signs and symptoms: Tinnitus Pain with loud noise exposure Impaired word understanding Loud patient's voice Hearing difficult in noisy environments
• Management: Formal audiology testing Acute hearing loss
o High dose steroidso Carbogen Inhalation (5% CO2 and
95% Oxygen) Chronic hearing loss o Cochlear implants
The Nucleus Hybrid L24 Cochlear Implant System
The U.S. Food and Drug Administration approved the first implantable device for people 18 and older with
severe or profound Sensorineural hearing loss of
high-frequency sounds in both ears.
The Nucleus Hybrid L24 Cochlear Implant System may help those with this specific kind of hearing loss who do
not benefit from conventional hearing aids.
The hybrid system is mainly used for candidates who have good low-frequency hearing but very poor high-frequency
hearing.
The hybrid works on the concept of combining
electrical stimulation for high frequency sound with
acoustic hearing for low frequency information in the
same ear.
Components of a cochlear implant
The basic part of this includes:
External part• Micro phone and sound processor• Transmitter
Internal part• A receiver and stimulator• Array of electrodes.
The Nucleus Hybrid L24 Cochlear Implant System combines the functions of a cochlear implant and a hearing aid.
This electronic device consists of an external microphone and sound processor that picks up sounds from the environment and converts them into digital code.
The sound processor transmits the digitally coded sound via the coil to the implant just under the skin.
The implant converts the digitally coded sound to electrical signals and sends them along the electrode array, which is positioned in the cochlea.
The implants electrodes stimulate the cochlea’s hearing nerve fibers, which relay the sound signals to the brain to produce hearing sensations.
Advantages
Helps those with Sensorineural hearing loss who do not benefit from conventional hearing aids.
No loss of residual natural hearing
Reduce the risk of infection and complications while improving the
patients ability to hear.
Preserve low frequency hearing
Minimal invasive surgery.
Limitations
Rapid fluctuations in sounds are not well
transmitted by cochlear implant.
Surgical issues like tinnitus, vertigo.
Medical costs , device, processor
and accessories are expensive.
conclusion Sensorineural hearing loss is the most common
form of hearing loss and occurs when there is a lesion in the inner ear or eighth cranial nerve (vestibulocochlear nerve) .
The Nucleus Hybrid L24 Cochlear Implant System is the first approved device by the FDA for Sensorineural hearing loss.
The hybrid L24 implant provides a better treatment option for suitable candidates with high frequency hearing loss.
References
E. Murugasu. Recent advances in the treatment of sensorineural deafness. Ann Acad Med Singapore 2005;34:313-21.
Harrison’s Principle of Internal Medicine, Vol 1 by Longo, Fauci Kasper, Hasper, Jamesoli Page No: 179-183 ,18 th edition.
www.fda.gov www.medscape.com www.nlm.nih.gov/medlineplus/ency/article/003291.html emedicine.medscape.com/article/856116-overview
– All data were collected from various sources.. only for educational purpose.
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