Wednesday, July 7, 2010

耳骨硬化影響聽力

聽力出現障礙,不少人會首先聯想至耳膜穿破或聽覺神經受損,但其實聲音傳遞除了依靠耳膜及聽覺神經,還有中耳的三塊小聽骨及內耳,倘若這些地方出現問題,也會影響聽力,其中一個例子便是耳骨硬化。

耳骨硬化主要發生於小聽骨中的蹬骨,即是與內耳連接的小聽骨,或是內耳前庭迷路位置的骨膜硬化,以至它們形狀出現改變,影響它們傳遞聲音的功能,令患者聽力下降。

耳骨硬化主要受遺傳影響,多於女士身上發生,而當她們體內賀爾蒙水平出現大幅改變時,即青春期、懷孕及更年期,特別容易誘發耳骨硬化發生。病發初時並沒有明顯病徵,受影響的骨質組織會呈海綿狀,直至骨質硬化時,便會出現耳鳴、暈眩或聽力下降的情況。

由於早期病徵不明顯,所以難以在骨質尚未硬化時介入處理,當病情已進入後期時,並沒有藥物可以治療耳骨硬化,只能透過手術,置換已呈硬化的小聽骨,改善聽力障礙。但手術後患者不能舉重、潛水等令耳朵受壓的活動,否則有機會令內耳中的內淋巴液滲出,進一步破壞耳朵組織。因此,部分患者為免麻煩,寧願選擇佩戴助聽器改善聽力。

There are two types of hearing loss: conductive hearing loss and sensorineural hearing loss. Abnormalities of the hearing bones or ossicles are examples of conductive hearing loss. It affects approximately 1% of the population and is more common in female. The most common age group ranges from 15-45. Diagnosis is by audiogram which shows a conductive hearing loss and absent stapedial reflex. Treatment is either hearing aid or surgery, which involves removing the fixated hearing bone and replacing it with a prosthesis. The success rate of the procedure is about 90%. After the operation, patients are advised to avoid diving and strenuous activities that could affect middle ear pressure and stability of the prosthesis.

Sources:
http://the-sun.on.cc/cnt/news/20100708/00410_033.html

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