If your speech discrimination is poor, speech may sound garbled. Normal hearing range is 250-8,000 Hz at 25 dB or lower.Ī word recognition test (also called speech discrimination test) assesses a person's ability to understand speech from background noise. Low bass tones range 50-60 Hz, high-pitched tones range 10,000 Hz or higher. The tone of sound is measured in frequencies (Hz). A whisper is about 20 dB, loud music ranges 80-120 dB, and a jet engine is about 180 dB. The loudness of sound is measured in decibels (dB). During the test, you will wear earphones and hear a range of sounds directed to one ear at a time. The movement of hair cells generates nerve signals that our brain then understands as sound.Ī pure tone audiometry test measures the softest, or least audible, sound that a person can hear. When the vibration hits the cochlea, it causes the liquid, and subsequently the hair cells, to move. The cochlea is a spiral tube filled with liquid and lined with hair cells that are microscopic in size. The stapes delivers vibrations to the cochlea in the inner ear. The ossicles consist of the malleus, incus, and stapes. Vibrations are passed along tiny bones (ossicles) in the middle ear. Vibrations are made when sound hits the eardrum. The outer ear collects sound waves from the environment and funnels them down the ear canal to the eardrum. If the Rinne test is negative for 256 Hz, 512 Hz, and 1024 Hz, the air-bone gap is 45-60 dB.Figure 1. If the Rinne test is negative for 256 Hz and 512 Hz and positive for 1024 Hz, the air-bone gap is 30-45 dB. If the Rinne test is negative or equal to the frequency of 256 Hz and positive for 512 Hz, the air-bone gap is 20-30 dB. The results and their interpretations are as follows: Rinne test also predicts the air-bone gap with the help of tuning forks of frequency 256 Hz, 512 Hz, and 1024 Hz. The negative result indicates air-bone gap of minimum of 15-20 dB. It indicates the conductive loss of hearing. If BC is longer or louder than AC, the Rinne test is negative. It could indicate normal hearing or sensorineural deafness. If AC is louder or more prolonged than BC, the Rinne test is positive. Interpretation of the results of the Rinne test is as follows: The patient informs the examiner which of the two sounds between air conduction and bone conduction were louder. If the patient can still hear the sound, it implies that AC is more significant than BC. The examiner brings the tuning fork beside the meatus when the patient stops hearing the sound. On the mastoid bone of the patient, the examiner places a vibrating tuning fork. It compares air conduction (AC) of the ear to bone conduction (BC). Two of the most common clinically useful tests for hearing loss are the Weber and Rinne test. There is direct stimulation of the cochlea as the vibrations conduct via the skull bones. To test BC, the examiner places the vibrating tuning fork's footplate on the mastoid bone. Thus, it is used to test the cochlea and the conducting mechanism. The tuning fork is in line with the meatus of the ear and the waves are conducted from the tympanic membrane to the inner ear. The examiner places a vibrating tuning fork near the external auditory canal at a distance of 2 cm for testing AC. The sound heard is louder for air conduction than for bone conduction. The tuning fork is activated by striking it to make it vibrate.Īir conduction (AC) and bone conduction (BC) tests use the tuning fork techniques. Likewise, lower frequency forks are also not preferred due to bone vibrations produced by them. Higher frequency forks are not preferred as they have a shorter decay time. The usual type of clinical testing for deafness is the tuning fork tests, which require tuning forks with different frequencies, 512 Hz frequency is considered ideal for clinical practice.
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