TYPE OF HEARING LOSS

Conductive hearing loss occurs when sound is not conducted efficiently through the outer ear canal to the eardrum and the tiny bones (ossicles) of the middle ear or it can also be caused by any disorder that unfavourably effects the middle ear's ability to transmit the mechanical energy to the stapes footplate. This results in reduction of one of the physical attributes of sound called intensity (loudness), so the energy reaching the inner ear is lower or less intense than that in the original stimulus.

Generally, the cause of conductive hearing loss can be identified and treated resulting in a complete or partial improvement in hearing. This type of hearing loss can often be corrected medically or surgically. Following the completion of medical treatment for cause of the conductive hearing loss, hearing aids are effective in correcting the remaining hearing loss. There are some possible causes of conductive hearing loss which are:

• Presence of a foreign body
• Impacted earwax
• Infection in the ear canal or also known as external otitis
• Fluid in the middle ear from colds
• Ear infection (otitis media)
• Allergies
• Absence or malformation of the outer ear, ear canal, or middle ear
• Poor eustachian tube function
• Perforated eardrum
• Swimmer's Ear (otitis externa)

The second type of hearing loss is called sensorineural hearing loss. Sensorineural hearing loss (SNHL) results from malfunction of inner ear structures (cochlea) or when there is damaged to the nerve pathways from the inner ear to the brain. This word can be divided into its two components - sensory and neural. The sensory component may be from damage to the organ of Corti or an inability of the hair cells to stimulate the nerves of hearing or a metabolic problem in the fluids of the inner ea

The neural or retrocochlear component can be the result of severe damage to the organ of Corti that causes the nerves of hearing to degenerate or it can be an inability of the hearing nerves themselves to convey neurochemical information through the central auditory pathways. Most of the time, SNHL cannot be medically or surgically corrected. This is the most common type of permanent hearing loss.

Like conductive hearing loss, sensorineural hearing loss reduces the intensity of sound, but it might also introduce an element of distortion into what is heard resulting in sounds being unclear even when they are loud enough. Once any medically treatable conditions have been ruled out, the treatment for sensorineural hearing loss is amplification through hearing aids. There are some possible causes of SNHL:

• Illnesses, e.g diabetes
• Drugs that are toxic to hearing
• Hearing loss that runs in the family (genetic or hereditary)
• Aging
• Head trauma
• Malformation of the inner ear
• Exposure to loud noise (NIHL)

 

A mixed hearing loss can be thought of as a sensorineural hearing loss with a conductive component overlaying all or part of the audiometric range tested. So, in addition to some irreversible hearing loss caused by an inner ear or auditory nerve disorder, there is also a dysfunction of the middle ear mechanism that makes the hearing worse than the sensorineural loss alone. When this occurs, the hearing loss is referred to as a mixed hearing loss.

The conductive component may be treated with medical treatment and reversal of the associated hearing loss, but the sensorineural component will most likely be permanent. Hearing aids can be beneficial for persons with a mixed hearing loss, but caution must be exercised by the hearing care professional and patient if the conductive component is due to an active ear infection.

 

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JENIS-JENIS MASALAH PENDENGARAN

Masalah Pendengaran Konduktif

Secara umumnya, punca masalah pendengaran konduktif boleh dikenal pasti dan dirawat. Dengan rawatan awal, ada kemungkinan bahawa masalah pendengaran akan pulih sepenuhnya atau bertambah baik. Rawatan biasanya melibatkan pengambilan ubat-ubatan atau pembedahan. Sekiranya pesakit masih mempunyai masalah pendengaran setelah rawatan diberikan, penggunaan alat bantuan pendengaran adalah digalakkan kerana ianya akan membantu penguatkan bunyi dan sekaligus membantu pesakit untuk mendengar dengan lebih baik. Antara punca-punca seseorang mengalami masalah  pendengaran konduktif ialah:

• Terdapatnya bendasing di dalam telinga
• Tahi telinga tersumbat
• Jangkitan kuman pada salur telinga (otitis externa)
• Terdapat cairan di dalam telinga tengah
• Jangkitan pada telinga tengah (otitis media)
• Alahan
• Kecacatan pada struktur telinga
• Tiub Eustachian yang tidak berfungsi dengan baik 
• Gegendang telinga berlubang

Masalah Pendengaran Sensorineural

• Mengambil ubat-ubatan yang boleh merosakkan telinga
• Mempunyai penyakit yang kronik
• Masalah pendengaran disebabkan keturunan (genetic)
• Usia lanjut (lebih dari 50 tahun)
• Kecederaan pada bahgian kepala 
• Terdedah kepada bunyi bising yang kuat

 

Masalah Pendengaran Campuran

 

Masalah pendengaran bercampur adalah gabungan masalah pendengaran sensorineural dan konduktif. Maksudnya, disebalik masalah pendengaran kekal pada telinga dalam dan saraf pendengaran, ada juga masalah / penyakit pada telinga luar dan tengah. Ini menyebabkan masalah pendengaran bertambah parah.

 

Disebabkan pesakit mengalami kedua-dua masalah konduktif dan sensorineural, pesakit perlulah mendapatkan rawatan untuk menyembuhkan penyakit yang dialami dan dalam masa yang sama menggunakan alat bantu pendengaran bagi membantu beliau mendengar.