Normal Audiogram: Understanding Normal Hearing Test Results Explained
Author: Dr Sagar Rajkuwar, ENT Specialist, Nashik, Maharashtra, India
🌐 www.entspecialistinnashik.com
Table of Contents
- Introduction
- What Is a Diagram?
- Deciphering Audiogram Symbols
- Audiogram Speech Sounds
- Examples of audiograms and levels of hearing loss
- How Do Audiograms Determine Hearing?
- Summary
- FAQ
Introduction
Your hearing is within the healthy range across various sound frequencies and volumes, as shown by a normal audiogram. It is one of the most critical tools employed by audiologists and ENT doctors to assess hearing capacity and identify initial hearing loss. If you’ve recently completed a hearing test and are curious about the meaning of your audiogram, comprehending the graph, symbols, and normal hearing levels can assist you in analyzing your findings with assurance.
You’ll find out what a typical audiogram looks like, how hearing is measured, and when to visit an audiologist or ENT doctor in this guide.
What Is a Diagram?
The outcome of a hearing test is shown on an audiogram, which is a graph. At various sound frequencies (pitches) and decibel levels, it displays the quietest noises a person can detect. To ascertain the kind, degree, and pattern of hearing loss, ENTs and audiologists employ audiograms.
Frequency (Hz), ranging from low to high pitches, is shown on the horizontal axis of the graph, while hearing level (dB HL) is displayed on the vertical axis. Higher hearing thresholds on the graph show improved hearing, while lower values indicate more hearing loss. The classification of hearing as normal, mild, moderate, moderately severe, severe, or profound is aided by the location of the test results.
Deciphering Audiogram Symbols
Audiograms employ standardized symbols to symbolize hearing levels in every ear:
- O (Red Circle): The threshold of hearing for air-conduction in the right ear.
- X (Blue Cross): Threshold of left ear air conduction hearing.
- Threshold of bone conduction in the right ear is < or [: .
- or ]: Threshold for left ear bone conduction.
These symbols are explained by a key or legend on the audiogram, which facilitates accurate interpretation of the results by healthcare experts.
Audiogram Speech Sounds
The “speech banana,” which represents the spectrum of noises utilized in spoken language, is another thing that an audiogram emphasizes. The pitch and loudness of typical speech sounds are shown by this shaded area.
For instance:
- When hearing loss first appears, “s,” “f,” and “th” are softer and harder to hear because they are high-pitched noises.
- Sounds with lower pitches, like “o,” “a,” and “u,” are louder and usually simpler to hear.
Conversations might be unclear, particularly in loud environments, if you have trouble understanding these speech noises.
Examples of audiograms and levels of hearing loss
Typical Hearing
People who have normal hearing are able to hear low-level sounds at every frequency range associated with speech. Their hearing thresholds are between -10 and 20 dB HL.
A bit of hearing loss
Those who have a minor hearing loss may find it difficult to hear gentle speech, discussions from a distance, or speech in crowded areas.
Mild Hearing Loss
Even when someone is speaking nearby, those with moderate hearing loss frequently have difficulty understanding a typical conversation.
Severe loss of hearing
Typically, persons with severe hearing loss can only hear extremely loud speech or sounds in their surroundings, like sirens, alarms, or crashing doors.
How Do Audiograms Determine Hearing?
A comprehensive hearing evaluation uses two fundamental testing techniques to produce an audiogram:
Testing Using Air Conduction
Sounds are administered via headphones or earphones during air conduction testing. The whole hearing system may be evaluated using sound passing via the inner, middle, and exterior ears.
Testing using bone conduction
If hearing loss is discovered, a bone conduction test is conducted using a tiny bone vibrator that is placed behind the ear. This equipment transmits sound waves straight to the cochlea, which is the inner ear, avoiding the middle and outer ear.
Knowing whether you have bone conduction or air conduction is useful for identifying the type of hearing impairment:
- Bone conduction hearing is superior to air conduction in conductive hearing loss because sound is trapped in the outer or middle ear.
- Sensorineural Hearing Loss: The bone and air conduction thresholds are equally reduced, suggesting damage to the cochlea or auditory nerve.
- Mixed Hearing Loss: Both air and bone conduction thresholds are decreased, with an air-bone gap demonstrating a combination of conductive and sensorineural hearing loss.
An audiogram offers useful information that enables ENT doctors and audiologists to identify hearing problems and recommend the best course of treatment, such as medicine, surgery, hearing aids, or cochlear implants.
Summary
A normal audiogram indicates that a person can hear low sounds over a large range of frequencies, with hearing thresholds typically ranging from -10 dB to 20 dB HL. By assessing air and bone conduction, audiograms aid in the identification of conductive, sensorineural, and mixed hearing loss. Early detection and treatment of hearing issues are possible with knowledge of your hearing test findings. If you have trouble hearing despite having a normal audiological test or if your audiogram is outside the normal range, speak with an ENT specialist or an audiologist for additional evaluation.
FAQ
1. What does a typical audiogram look like?
A normal audiogram reveals hearing thresholds in the range of -10 dB to 20 dB HL across the tested frequencies, suggesting good hearing.
2. On an audiogram, what do the symbols O and X mean?
Right ear air conduction is represented by O (Red).
X (Blue): Air conduction left ear
3. What frequencies are measured in a hearing test?
The range of frequencies from 250 Hz to 8000 Hz, which is crucial for comprehending speech, is typically covered by hearing tests.
4. What is regarded as standard hearing?
A person with normal hearing can hear sounds between -10 dB and 20 dB HL at all frequencies that have been tested.
5. Is it possible to have normal audiograms but still have hearing issues?
Indeed. Despite a normal audiogram, some individuals may have trouble hearing in noisy surroundings. Further hearing tests could be suggested.
6. What exactly is air conduction testing?
Testing with air conduction gauges hearing through the whole hearing route using headphones or earbuds.
7. What does it mean to undergo bone conduction testing?
Bone conduction testing bypasses the middle and outer ear to examine the auditory nerve and inner ear function.
8. Why is an audiogram necessary?
It assists in determining the type and severity of hearing loss, making early diagnosis possible, and directing the best course of action.
9. How frequently should grown-ups get their hearing checked?
Healthcare providers should advise adults to get a baseline hearing test and repeat it if their hearing changes.
10. When should I consult an ENT specialist?
Seek medical attention if you suffer from hearing loss, tinnitus, dizziness, ear discomfort, ear discharge, or abrupt changes in your hearing.
Medical Disclaimer:
This article is intended for educational and informational purposes only and should not be considered a substitute for professional medical advice, diagnosis, or treatment. Hearing test results should always be interpreted by a qualified ENT specialist or audiologist. If you experience sudden hearing loss, persistent tinnitus, dizziness, ear pain, or any concerning symptoms, seek prompt medical evaluation.
References
- World Health Organization (WHO). World Report on Hearing.
- American Speech-Language-Hearing Association (ASHA). Understanding Audiograms.
- National Institute on Deafness and Other Communication Disorders (NIDCD). Hearing Tests.
- American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS). Hearing Loss Evaluation.
- Centers for Disease Control and Prevention (CDC). Hearing Loss and Prevention.
- British Society of Audiology (BSA). Recommended Procedure for Pure Tone Audiometry.
- National Health Service (NHS). Hearing Tests and Hearing Loss.
