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Audiology

Audiology Clinical Masking

Hearing loss is common in the United States, with approximately 13% of people over 12 years of age reported experiencing hearing loss in both ears on clinical testing. Therefore, it is vital that audiologists can accurately measure patients' hearing to help provide the best management for hearing loss. If a hearing loss is detected, it is also important to understand whether it is a conductive or sensorineural hearing loss, as both possible underlying pathophysiology and management options diffe

v1 · Reviewed Nov 7, 2026 by Automated Clinical Reviewer (Strict Verbatim v1)
  • Rarer but more serious causes of hearing impairment, such as vestibular schwannoma, a benign tumor arising from the Schwann cells of the vestibular nerve, should be excluded if unilateral hearing loss is detected.
  • A pure tone audiogram is a behavioral test of hearing, where a tone at a specific frequency is presented to the test ear by over-ear headphones or inserted earphones.
  • The loudness of the tone is altered to find the quietest tone in decibels (dB) which can be heard 50% of the time, which is termed the threshold.
  • Typically 6 to 8 frequencies are tested, between 250 Hz and 8000 Hz, and the process is repeated for the other ear.
  • Clinical masking in audiology refers to introducing noise to the non-test ear during a pure-tone audiogram.
  • Cross-hearing occurs when a tone presented to the test ear overcomes interaural attenuation, which refers to the loss of acoustic energy as sound waves travel transcranially to the contralateral ear.
  • for air conduction testing, masking is employed when the difference between unmasked thresholds in both ears is greater than 40 dB (or 55 dB when using insert earphones), which is thought to be the minimum interaural attenuation for pure tones.
  • There is negligible interaural attenuation for bone conduction, which is assumed to be 0 dB for bone conduction testing, as sound travels via bone conduction through the skull to both cochleae.
  • immittance (tympanometry)
  • When non-masked hearing thresholds are established, and it has been determined that masking should be employed, the effective masking threshold should be obtained for the non-test ear.
  • The masking noise in the non-test ear is increased in intervals, with further testing of the pure tone thresholds in the test ear with each new interval until a plateau threshold is found.
  • Once a new accurate threshold has been found for each frequency in both ears, these results are plotted onto an audiogram, as seen below.
  • Awareness, assessment, and management of hearing loss with amplification devices are important, with sound amplification being shown to positively impact the quality of life.
  • Conductive hearing loss occurs when sound waves are inhibited from reaching the cochlea, primarily due to mechanical pathology of the pinna, ear canal, or middle ear.
  • Sensorineural hearing loss occurs due to pathology of the inner ear or the cochlear nerve from the inner ear to the auditory cortex.
  • In situations with a sizeable conductive component in both ears, it may not be possible to mask effectively at all.
  • The masking noise crosses over to the test ear as the test tone increases, creating a masking dilemma.
  • In this circumstance, the unmasked responses are labeled with an asterisk, and it is stated that masking is not possible without over-masking.
  • A single pure-tone audiogram should be validated, meaning the results are analyzed and should be consistent with the clinical history, examination findings, immittance (tympanometry), and speech audiometry.
  • Inconsistent results may highlight the need for further investigation, with repeated audiological testing, to ensure the accuracy of findings.
  • review
    Audiology Clinical Masking. StatPearls [Internet] — Clare J. Perkins, Scott Mitchell — StatPearls Publishing, 2022

Decision support only. Verify against local protocols and current labeling. Source: www.ncbi.nlm.nih.gov