Pure tone audiometry
This test assesses your hearing sensitivity across a range of frequencies (pitches), which are involved in speech perception. It involves listening to sounds via headphones and responding by pressing a button every time a sound is heard. It takes approximately 20 minutes to complete. With regard to degree of hearing loss, the audiologist is looking for quantitative information. Hearing levels are expressed in decibels (dB) based on the pure tone average for the frequencies 250 to 8000 Hz and discussed using descriptors related to severity:
- Normal hearing (up to 20 dB HL)
- Mild hearing loss (21 to 40 dB HL)
- Moderate hearing loss (41 to 70 dB HL)
- Severe hearing loss (71 to 95 dB HL)
- Profound hearing loss (95 dB HL or greater)
With regard to the type of hearing loss the audiologist is looking for information that suggests the point in the auditory system where the loss is occurring (the origin/source of the problem).
After assessment/diagnostic procedures are complete, if necessary, the option of hearing aid amplification is discussed with the patient. The final decision, as to the type of hearing aid fitted, is based on an audiological assessment of the patient’s individual suitability.
Tympanometry and stapedial reflexes (immittance testing)
This is a quick objective test used to assess middle ear function. It involves placing a soft earplug in the ear which records middle ear pressure. This may include listening to some loud noises for a few minutes in order to measure the reflex of the muscles in the middle ear.