Normal hearing is operationally defined as a four-frequency average threshold below 25 dB HL.

Evidence

All participants had normal hearing bilaterally, defined by four frequency average hearing loss thresholds (500 Hz, 1 kHz, 2 kHz and 4 kHz) of less than 25 dB HL. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4163

Categorization

• DEFINE: Operational definition of ‘normal hearing’ used in audiology research.
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 4163
• XREF: connects to: Standards accept up to 25 dB of hearing loss as medically normal; Hearing thresholds are clinically tested at octave-spaced frequencies covering the speech range; Averaging hearing loss across frequencies can mask serious impairment — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2360 (+2 more)

Broader Connections

• Averaging hearing loss across frequencies can mask serious impairment #complicates (0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2360
• Hearing thresholds are clinically tested at octave-spaced frequencies covering the speech range #expands (0.75)
• Noise-induced hearing loss first appears near 4 kHz as an audiometric notch #expands (0.72)
• Audiometric testing requires ambient sound below 35 dBA with frequency-specific limits #expands (0.70) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2344