My advice to my patients with hearing loss is to do a fresh hearing test every 12-18 months and keep a record of your hearing test results. In addition, it is good to be able to read your test results. Continue reading this article to learn more about Pure Tone Audiometry (PTA) and how to read your audiogram.
Note: This article only discusses the basics of an audiogram so you can have a better understanding of your hearing test results.
What is an audiogram?
A comprehensive hearing test could include several different tests that collectively help your audiologist understand the level of your hearing loss and where it comes from. Pure Tone Audiometry is the most important piece of information that your hearing care professional will obtain. The result of this test is reflected on a graph called an audiogram (see below). An audiogram indicates the threshold of your hearing in the left and right ear at each frequency over 250 Hz to 8 KHz.
A hearing test audiogram
Let's take a closer look at the above audiogram.
Audiogram scales - On the horizontal axis you can see the frequency scale which is from 125 Hz to 8 kHz. In the United Kingdom, most hearing tests are usually done over 250 Hz to 8 kHz. The vertical axis of the audiogram is from -10 dB to 120 dB sound intensity. The patient will hear pure tone sounds (stimulus) over this frequency range in the left and right ear. The sound is more audible at the start and then becomes softer and softer. You will be expected to signal by raising your hand or pressing a push button when you can hear the stimulus sound.
Thresholds - Your hearing thresholds are the quietest sound that you managed to hear at each frequency, at the right and the left side. Your hearing thresholds are presented in Red circles for the right ear and Blue crosses for the left ear. This colour coding is Internationally accepted and carries on to your hearing aids and pretty much everywhere in the domain of hearing care and audiology. The audiologist may use a calibrated headphone or in-the-canal speakers to do what we call aid conduction (or AC) tests. An AC measures your overall hearing thresholds assessing your middle and inner ear together. Another little buzzer will be placed behind your ears on your mastoid bone that sends the stimulus directly to your inner ear (your Chochlea to be exact). This measurement is called Bone Conduction or BC. Such as a test that measures the hearing thresholds of your inner ear. The BC thresholds are markers by < and > and when masking is needed by [ and ] for the left and right side separately. I don't want to make you confused by discussing more details about the test techniques (in particular masking). Please do not hesitate to leave a comment at the end of this article if interested to learn more.
Hearing loss levels - The colour coding on an audiogram (some do not have it), shows the severity of your hearing loss. A hearing threshold falling between zero to 25 dB is categorized as no hearing loss. You will have Mild hearing loss when a hearing threshold is measured between 25 to 40 dB, and so on for Moderately Severe, Severe and Profound hearing loss.
Speech banana - The other piece of information that I usually map on the audiogram and walk my patients through after a hearing test is the speech banana. When you map the consonants that build our words and phrases on an audiogram they can be seen as a banana, hence the speech banana. All the vowels, as well as z, n, m, r, j,... form a group which is low frequency and has a range of intensity about 30 to 60 dB. In the above audiogram, you can see that this group is mostly below the line of hearing thresholds of the patient, hence the patient can hear them naturally (in a conversation in a quiet room). The second group consist of ph, ch, sh and g. This group in mid-frequency and in terms of energy level is spread over 25 to 50 dB. In the above example, the lines of hearing of the patient cut through this group so very likely the patient occasionally hears them when in a conversation in a quiet room. The last group that most of us at age 50 start losing is the 3rd group consisting of k, t, f, s, th which are high frequency by nature and at a low energy range of 20 to 30 dB. As you can see on the above audiogram, the hearing threshold of the patient at high frequency is about 60 dB, therefore the patient is not able to hear the 3rd group of consonants in a conversation naturally, even in a very quiet room.
Life sounds - If you look carefully some signs and symbols are pinned on the audiogram, elements such as an aeroplane, a car noise and a bird. I usually map these elements on the audiogram as they can give a sense to the patient as to why he or she is not able to hear these life-sound elements. Again, if the element is below your threshold line you can hear it naturally, and if the sound element is above your line of hearing you are not able to hear it naturally.
I hope that the above brief helps you understand your audiogram better. Please do not hesitate to post your questions in the comment box at the bottom of this page.
Also, you can book a free hearing test in our clinic in Crystal Palace, or a free online consultation with our audiologist to discuss your hearing loss.
References:
Harrison RV. How can the audiogram be more useful? Journal of Otolaryngology - Head & Neck Surgery. 2016;45(1). doi:10.1186/s40463-016-0132-8
Klyn, Niall A.M. PhD; Rutherford, Cherilee AuD; Shrestha, Neeha; Lambert, Bruce L. PhD; Dhar, Sumitrajit PhD. Counselling with the Audiogram. The Hearing Journal 72(11):p 12,13,17, November 2019. | DOI: 10.1097/01.HJ.0000612568.43372.73
Niall A. M. Klyn, Claire Letendre, Neeha Shrestha, Bruce L. Lambert & Sumitrajit Dhar (2021) Interpretability of the audiogram by audiologists and physician non-specialists, International Journal of Audiology, 60:2, 133-139, DOI: 10.1080/14992027.2020.1805129
Ibrahim Almufarrij, Harvey Dillon & Kevin J. Munro (2023) Do we need audiogram-based prescriptions? A systematic review, International Journal of Audiology, 62:6, 500-511, DOI: 10.1080/14992027.2022.2064925
