Monday, June 6, 2011

Hearing loss - Diagnosis

Diagnosis of hearing loss is based on an examination of the ear, supplemented by a series of explorations of auditory function to assess the degree of hearing loss (acoustic examination quantity).Other tests indicate the location, nature and type of hearing loss in the case (transmission, reception or mixed nerve).
The first step in diagnosis is the examination of the ear. Using an otoscope (an instrument for viewing the eardrum and ear canal), the doctor look for signs of an ear infection.
The following tests are performed to determine the cause of hearing loss:
Audiometers - is a process of investigation of auditory function, which determines the minimum threshold for different frequencies hearing in both ears. The results are then compared with what is considered normal hearing.
Discrimination tests - are performed to assess the ability to refer patients differences between similar words. The patient has to distinguish between similar words monosyllabic. If a hearing loss transmission capability of discrimination is normal, unlike the perception of hearing loss.
Tympanometry - exam that allows highlighting how the eardrum responds to changes in pressure in the ear canal.Tympanometry involves inserting a catheter equipped with a microphone in the ear of the patient and the change in pressure in the ear canal, while you listen to different sounds. Abnormal results indicate a hearing loss timpanometriei transmission.The exam does not require the active participation of the patient and is commonly used in children.
Rinne test - a test that allows differentiation between the hearing loss of the transmission and perception. Compare test hearing by air and bone at about the same ear. To test hearing by air, put vibrating tuning fork is placed a few inches from the patient's ear.To test the sound transmission by bone, the foot placed in vibration range specification is placed on the mastoid bone.If the duration of perception by air is reduced, while the transmission is normal bone, hearing loss is the transmission. If both the bone and air transmission is low, or mixed hearing loss is the perception.Patients with hearing loss of perception require further investigation to look for other conditions such as Meniere's disease or brain tumors.
Brain stem auditory evoked potentials (PEA) - test that measures nerve impulses in the brainstem. Results are abnormal in patients with sensorineural hearing loss or brain tumors.

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