Audiogram Essentials for Otolaryngologists
Introduction
Audiograms are indispensable in otolaryngology, providing essential insights into a patient’s hearing capabilities. This comprehensive guide is designed for otolaryngologists and medical students preparing for board examinations, offering an in-depth understanding of audiograms, their interpretation, and their role in diagnosing and managing hearing loss.
Understanding Audiograms
An audiogram is a graph depicting a person’s hearing sensitivity across different frequencies. It is fundamental for determining the type, degree, and configuration of hearing loss. However, it’s crucial to note that the pure-tone audiogram only measures hearing sensitivity and has limited utility in assessing central auditory processing or the auditory processing of complex sounds like speech and music [Kassjański, Kulawiak & Przewoźny, 2022].
Limitations of Audiograms
Despite being a primary audiological tool, the pure-tone audiogram has limitations. Normal or near-normal pure-tone thresholds can sometimes be observed despite underlying cochlear damage. There are instances of patients with acoustic neuromas exhibiting normal pure-tone thresholds. Additionally, in cases of profound deafness, depressed pure-tone thresholds may not accurately reflect the status of the peripheral auditory system [Klyn et al., 2020].
Complementing Audiograms with Other Tests
Given the limitations of the pure-tone audiogram, other tests like ultra-high-frequency audiometry and non-behavioral measures are recommended to detect hidden hearing loss and cochlear synaptopathy. Self-report questionnaires may help identify auditory dysfunction in individuals with normal hearing thresholds [Li et al., 2021].
Audiogram Display Formats
The display format of audiograms can affect comprehension of pure tone audiometry data. Studies have shown that overlaid thresholds on a chart are preferred over numeric tables or multi-dimensional charts for computerized audiometry displays [Hirabayashi et al., 2022].
Audiograms in Telehealth
The rise of telehealth has introduced automated audiometry using pre-defined diagnostic protocols, which accurately identify disabling, conductive, and unilateral hearing loss, thus improving tele-audiology service delivery [Shilo et al., 2021].
High-Frequency Audiometry
High-frequency audiometry, not typically included in routine hearing examinations, is valuable in specific cases, such as patients treated for tumors of the pontocerebellar angle. This method can detect clinically significant asymmetry or pathological elevation of the hearing threshold at frequencies above 8 kHz [Svobodová et al., 2022].
Conclusion
Audiograms are a crucial tool in otolaryngology but are not without limitations. Understanding these limitations and using audiograms in conjunction with other tests can provide a more comprehensive assessment of a patient’s hearing health. Advancements in technology, such as automated audiometry in telehealth, are opening new avenues for improving the diagnosis and management of hearing loss.
FRCS ORL-HNS / Otolaryngology Board examinations Question for Audiogram Essentials:
Question 1
A 35-year-old patient presents with difficulty understanding speech in noisy environments and occasional tinnitus, but has normal results on a standard audiogram. Which of the following is the maximum in all likelihood diagnosis?
A) Otitis media
B) Acoustic neuroma
C) Cochlear synaptopathy
D) Central deafness
E) Myringosclerosis
Answer: C. Cochlear synaptopathy
Explanation: This patient’s symptoms suggest hidden hearing loss or cochlear synaptopathy, conditions that can present with difficulty understanding speech in noise or other complaints such as tinnitus, but may not be detected on standard audiograms.
Question 2
A 45-year-old patient with a history of cranial radiation therapy during childhood presents with sensorineural hearing loss. What is the most likely cause of this patient’s hearing loss?
A) Otitis media
B) Acoustic neuroma
C) Cochlear synaptopathy
D) Radiation-induced damage
E) Myringosclerosis
Answer: D. Radiation-induced damage
Explanation: Childhood cancer survivors treated with cranial radiation therapy have a higher risk of sensorineural hearing loss, which may worsen over time.
Question 3
A 50-year-old patient presents with hearing loss. The patient is given a hearing aid and asked to select their own signal processing parameters using a simple interface. What is the most likely outcome of this approach?
A) The patient will select parameters that are significantly different from those selected by an audiologist.
B) The patient will select parameters that are similar to those selected by an audiologist.
C) The patient will not be able to select appropriate parameters.
D) The patient will select parameters that result in worse sound quality than clinician-selected parameters.
E) The patient will select parameters that result in no change in sound quality compared to clinician-selected parameters.
Answer: B. The patient will select parameters that are similar to those selected by an audiologist.
Explanation: Research has shown that users can effectively select effective amplification parameters for their hearing aids using a simple interface, with some reporting better sound quality than clinician-selected parameters.
Question 4
A 30-year-old patient presents with hearing loss. The patient undergoes pure-tone audiometry, which shows normal results. What is the most likely explanation for this patient’s hearing loss?
A) The patient does not have hearing loss.
B) The patient has central auditory involvement.
C) The patient has otitis media.
D) The patient has an acoustic neuroma.
E) The patient has myringosclerosis.
Answer: B. The patient has central auditory involvement.
Explanation: The pure-tone audiogram, though fundamental to audiology, presents limitations, especially in the case of central auditory involvement. Normal or near-normal pure-tone thresholds sometimes are observed despite cochlear damage or central auditory involvement.
Question 5
A 40-year-old patient presents with hearing loss. The patient undergoes automated audiometry using pre-defined diagnostic protocols in an asynchronous telehealth model. What is the most likely outcome of this approach?
A) The patient will be misdiagnosed.
B) The patient will be accurately diagnosed.
C) The patient will not be diagnosed.
D) The patient will be overdiagnosed.
E) The patient will be underdiagnosed.
Answer: B. The patient will be accurately diagnosed.
Explanation: Pre-defined diagnostic protocols applied asynchronously to automated audiometry provide accurate identification of disabling, conductive and unilateral hearing loss. This approach has the ability to enhance synchronous and asynchronous tele-audiology carrier transport.