Audiograms

Summary

This video provides an in-depth tutorial on audiometry, focusing on how audiograms help diagnose hearing loss. It explains the process of testing a patient’s hearing with pure tones at varying frequencies and intensities, and how tuning fork tests like Rinne’s and Weber’s assist in identifying conductive and sensory neural hearing loss. The video covers common hearing conditions, including presbycusis, noise-induced hearing loss, and Meniere’s disease, and demonstrates how to interpret audiograms to differentiate between normal hearing, conductive, sensory neural, and mixed hearing losses. Understanding these concepts is essential for accurate diagnosis and treatment of hearing disorders.

Takeaways

• 😀 Audiometry involves testing air and bone conduction to assess hearing thresholds at various frequencies and intensities.
• 😀 An audiogram is a graphical representation that helps diagnose different types of hearing loss by plotting hearing thresholds.
• 😀 Rinne's and Weber's tests are bedside methods to compare air and bone conduction, helping identify the type of hearing loss.
• 😀 Normal hearing in adults is typically between 0 and 20 decibels across all frequencies, as indicated by an audiogram.
• 😀 Conductive hearing loss occurs when bone conduction is normal but air conduction is impaired, often due to issues in the outer or middle ear.
• 😀 Sensory neural hearing loss is diagnosed when both air and bone conduction are impaired, indicating issues with the cochlea or auditory nerve.
• 😀 Mixed hearing loss is a combination of both conductive and sensory neural loss, with a gap between air and bone conduction on the audiogram.
• 😀 Common causes of conductive hearing loss include otitis media, otosclerosis, and middle ear tumors, while sensory neural loss can result from conditions like presbycusis, noise-induced hearing loss, and acoustic neuromas.
• 😀 Audiograms can help identify the specific frequencies at which hearing loss occurs, which is crucial for diagnosing conditions like noise-induced hearing loss and presbycusis.
• 😀 The speech banana concept on the audiogram illustrates how losing hearing at certain frequencies affects speech comprehension, especially consonants and high-frequency sounds.

Q & A

What is audiometry and how is it performed?

Audiometry is a test used to measure a person's ability to hear different frequencies at varying intensities. It is performed by playing pure tone sounds through headphones and having the patient respond when they hear the sounds. The intensity of the sound is adjusted in 10 decibel steps until the patient can no longer hear it, then the intensity is increased in 5 decibel steps to find the hearing threshold.

What does an audiogram represent?

An audiogram is a graphical representation of a person's hearing ability across a range of frequencies. The x-axis represents frequency in Hertz (Hz), and the y-axis represents intensity in decibels (dB). Normal hearing for an adult is between 0 and 20 dB across all frequencies.

How does the Rinne test work and what does it measure?

The Rinne test compares air conduction to bone conduction. Air conduction involves sound traveling through the ear canal and middle ear, while bone conduction involves vibrations transmitted directly to the inner ear through the bones of the skull. A positive Rinne test occurs when air conduction is louder than bone conduction, indicating normal hearing, while a negative Rinne test suggests a possible conductive hearing loss.

What is the difference between conductive and sensorineural hearing loss as shown on an audiogram?

Conductive hearing loss is indicated on an audiogram when air conduction is worse than bone conduction, suggesting a problem in the outer or middle ear. Sensorineural hearing loss is shown when both air conduction and bone conduction are similarly affected, indicating damage to the inner ear or auditory nerve.

What is the role of the Weber's test in diagnosing hearing loss?

The Weber's test helps determine the type of hearing loss. It involves placing a tuning fork on the forehead or crown of the head to see which ear hears the sound louder. Lateralization to the affected ear suggests conductive hearing loss, while lateralization to the unaffected ear suggests sensorineural hearing loss.

What are some common causes of conductive hearing loss?

Common causes of conductive hearing loss include otitis media (middle ear infection), perforation of the tympanic membrane, otosclerosis, foreign objects in the ear canal, and cholesteatoma.

What is presbycusis and how does it appear on an audiogram?

Presbycusis is age-related hearing loss, typically affecting the high frequencies. On an audiogram, it shows bilateral high-frequency sensorineural hearing loss. The patient may have difficulty hearing high-pitched sounds, such as consonants in speech.

How does noise-induced hearing loss present on an audiogram?

Noise-induced hearing loss often shows a characteristic dip around 4000 Hz on the audiogram. This occurs due to permanent damage to the hair cells in the cochlea caused by prolonged exposure to loud noises.

What does a 'dead ear' refer to, and what are its potential causes?

'Dead ear' refers to a condition where no response can be registered during the audiometric test, suggesting the ear is nonfunctional. Common causes include labyrinthitis, trauma to the temporal bone, and post-surgical damage, such as after the removal of an acoustic neuroma.

What is mixed hearing loss, and how is it diagnosed on an audiogram?

Mixed hearing loss occurs when both conductive and sensorineural hearing loss are present in the same ear. On an audiogram, there is a significant gap between air conduction and bone conduction thresholds, indicating both middle ear and inner ear involvement.