AudiometryAn audiometry exam tests your ability to hear sounds. Sounds vary based on their loudness (intensity) and the speed of sound wave vibrations (tone). Hearing occurs when sound waves stimulate the nerves of the inner ear. Eventually the sound travels along nerve pathways to the brain. Sound waves can travel to the inner ear through the ear canal, eardrum, and bones of the middle ear (air conduction), or through the bones around and behind the ear (bone conduction). The INTENSITY of sound is measured in decibels (dB):
- A whisper is about 20 dB
- Loud music (some concerts) is around 80 – 120 dB
- A jet engine is about 140 – 180 dB
- Sounds greater than 85 dB can cause hearing loss after a few hours. Louder sounds can cause immediate pain, and hearing loss can develop in a very short time.
The TONE of sound is measured in cycles per second (cps) or Hertz:
- Low bass tones range around 50 – 60 Hz
- Shrill, high-pitched tones range around 10,000 Hz or higher
The normal range of human hearing is about 20 Hz – 20,000 Hz. Some animals can hear up to 50,000 Hz. Human speech is usually 500 – 3,000 Hz.
Services1. Pre-employment / Pre-placement audiometry 2. Baseline and Periodic audiometry for Medical Surveillance 3. Provision of audiometric testing facility for ENT specialists
Audiometry test in progress
Example of an Audiogram