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"Conventional" pure tone audiometry (testing frequencies up to 8 kHz) is the basic measure of hearing status. [6] For research purposes, or early diagnosis of age-related hearing loss, ultra-high frequency audiograms (up to 20 kHz), requiring special audiometer calibration and headphones, can be measured. [7]
Conventional audiometry tests frequencies between 250 hertz (Hz) and 8 kHz, whereas high frequency audiometry tests in the region of 8 kHz-16 kHz. Some environmental factors, such as ototoxic medication and noise exposure, appear to be more detrimental to high frequency sensitivity than to that of mid or low frequencies. Therefore, high ...
The standard and most common type of hearing test is pure tone audiometry, which measures the air and bone conduction thresholds for each ear in a set of 8 standard frequencies from 250Hz to 8000Hz. The test is conducted in a sound booth using either a pair of foam inserts or supraural headphones connected to an external audiometer.
There is also high frequency Pure Tone Audiometry covering the frequency range above 8000 Hz to 16,000 Hz. Threshold equalizing noise (TEN) test; Masking level difference (MLD) test; Psychoacoustic (or psychophysical) tuning curve test; Speech audiometry is a diagnostic hearing test designed to test word or speech recognition. It has become a ...
Given that hearing loss can vary by frequency and that audiograms are plotted with a logarithmic scale, the idea of a percentage of hearing loss is somewhat arbitrary, but where decibels of loss are converted via a legally recognized formula, it is possible to calculate a standardized "percentage of hearing loss", which is suitable for legal ...
The threshold of hearing is frequency-dependent and it has been shown that the ear's sensitivity is best at frequencies between 2 kHz and 5 kHz, [5] where the threshold reaches as low as −9 dB SPL. [6] [7] [8]
Hearing loss due to chemicals starts in the high frequency range and is irreversible. It damages the cochlea with lesions and degrades central portions of the auditory system. [72] For some ototoxic chemical exposures, particularly styrene, [73] the risk of hearing loss can be higher than being exposed to noise alone.
As dogs hear higher frequency sounds than humans, they have a different acoustic perception of the world. [24] Sounds that seem loud to humans often emit high-frequency tones that can scare away dogs. Whistles which emit ultrasonic sound, called dog whistles, are used in dog training, as a dog will respond much better to such levels. In the ...