Normal-hearing classification requires thresholds below 30 dB HL at all standard frequencies

Evidence

Listeners with audiometric thresholds of < 30 dB HL at all the frequencies between 125 and 4000 Hz in both ears were classified as normal-hearing; otherwise, as (mildly) hearing-impaired. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1031

Categorization

Category: Definitional Content

• DEFINE: Specific operational definition of ‘normal-hearing’ used across audiology studies — a usable baseline for the reader’s physiology understanding.

Related

• Normal hearing is defined as thresholds below 30 dB across 125-4000 Hz (similarity 0.97)
• Normal hearing is operationally defined as a four-frequency average threshold below 25 dB HL. (similarity 0.89)
• Standards accept up to 25 dB of hearing loss as medically normal (similarity 0.88)
• Normal-hearing EEG listeners were screened to 20 dB HL at octave bands (similarity 0.82)
• The 0 dB HL audiometric zero varies across frequency by design (similarity 0.82)
• Hearing thresholds vary individually but share a common perceptual order (similarity 0.82)
• WHO defines disabling hearing loss as a 40 dB threshold shift for adults (similarity 0.81)
• Audibility thresholds can be expressed on physical or perceptual decibel scales (similarity 0.81)
• Speech intelligibility is the standard criterion for hearing function (similarity 0.81)
• Hearing-impaired listeners vary more than normal hearers in quiet threshold, complicating averaging (similarity 0.81)
• Hearing-impaired perception studies illuminate the mechanisms behind normal hearing (similarity 0.81)
• Blind-tested listeners with normal hearing produce reliable, measurement-grade subjective ratings (similarity 0.81)
• Mild SNHL elevates thresholds from 15 to 30 dB across frequency (similarity 0.81)
• The 1935 Beasley survey first established US normal-hearing thresholds (similarity 0.80)
• Pitch perception differs across listeners despite normal hearing thresholds (similarity 0.80)