Audiological Evaluation
Pure Tone Audiometry
Pure-tone audiometry is the standard method of determining the degree, type, and configuration of hearing loss.
Pure tones at selected frequencies are presented through either earphones (air conduction) or a vibrator pressed against the mastoid portion of the temporal bone (bone conduction), and the minimal level that the subject can hear (threshold) is determined for each frequency.
Speech Audiometry
Speech Audiometry test is performed with audiometer by our expert audiologist team.
- The speech reception threshold (SRT): The SRT is a test of hearing sensitivity for speech and should reflect the hearing level for pure tones in the speech range.
- The speech discrimination(SDT): the SDT test is a measure of the patient's ability to understand speech when it is presented at a level that is easily heard.
In patients with eighth nerve lesion speech discrimination scores can be severely reduced.
Special Test(TDT,SISI)
- Tone Decay Test (TDT)The tone decay test is used to detect retro cochlear pathology with measure auditory fatigue.
- SHORT INCREMENT SENSITIVITY INDEX TEST (SISI)The SISI test is still widely used to determine cochlear pathology in patients. This test is based on a phenomenon known as recruitment (abnormal loudness growth).
Impedance Audiometry
Impedance audiometry is to determine the status of the tympanic membrane and middle ear via tympanometry. The another purpose of this test is to evaluate acoustic reflex pathways, which include cranial nerves (CN) VII and VIII and the auditory brainstem
Brain Stem Evoke Responses Audiometry (BERA)
BERA is an effective and non-invasive means of assessing the functional status of the auditory nerve and brainstem auditory sensory pathway. The electrical impulses changes in brain can be recorded from scalp electrodes at 0 to 10 msec (early), 10 to 50 msec (middle), and 50 to 500 msec (late) following a click (a high-frequency stimulus). The early potentials reflect electrical activity at the cochlea, eighth cranial nerve, and brain stem; the later potentials reflect cortical activity. Computer averaging of the responses to 1000 to 2000 clicks separates the evoked potentials from background noise. Early evoked responses may be used to estimate the magnitude of hearing loss and to differentiate among cochlea, eighth nerve, and brain stem lesions.
Oto Acoustic Emissions(OAE)
The otoacoustic emission test (OAE) measures hair cell function in the inner ear. An emission refers to the sound generated within the normal cochlea of the ear in response to stimulation. OAE testing is used for a number of reasons, including screening of infants and other special populations.
Paediatric Audiology
- Newborn hearing screening and follow up diagnostic assessment.
- Electro-physiological assessment under natural sleep or sedation.
- Behavioural hearing assessment.
- Full investigation of hearing loss including processing disorders.