The human sensory apparatus operates across extraordinary ranges of physical energy, translating subtle environmental disturbances into rich conscious experiences. At the foundational boundary of hearing lies the auditory threshold, a fundamental psychophysical marker demarcating the minimum acoustic energy necessary to evoke an auditory sensation. Understanding this perceptual borderline illuminates not only the bio-mechanical elegance of the peripheral and central auditory systems but also the statistical and probabilistic nature of human perception itself.
Auditory Threshold
1. Concise Definition
The auditory threshold denotes the lowest sound pressure level or physical acoustic energy of a pure tone or complex sound wave that an individual can reliably detect in the absence of extraneous background noise. In classical psychophysics, it is operationally defined as the stimulus intensity at which an organism detects the presence of sound on a specified percentage of experimental trials, conventionally 50 percent.
Beyond this absolute boundary, the construct also encompasses the difference threshold (or just noticeable difference), which measures the smallest perceptible change in frequency, intensity, or temporal duration between two acoustic stimuli. Rather than serving as an immutable physical line, the auditory threshold represents a dynamic psychophysical interface governed by peripheral mechanics, neurobiological transduction, cognitive decision criteria, and environmental acoustics.
2. Etymology & Linguistic Origin
The term is a compound derived from classical Latin and Germanic linguistic roots. The adjective auditory originates from the Latin verb audire, meaning “to hear,” which developed into the Late Latin substantive auditorium (a place of hearing) and the adjectival form auditorius, signifying “pertaining to hearing.” This root entered Early Modern English during the sixteenth century to categorize biological structures and faculties associated with the perception of sound.
The noun threshold descends from the Old English þerscold or þrescold, related to the Old Norse þreskoldr and the Proto-Germanic threskan (to thresh, stamp, or tread). Historically designating the sill of wood or stone beneath a doorway that one treads upon when entering a structure, the term acquired an abstract philosophical and scientific meaning in nineteenth-century German philosophy and psychophysics as die Schwelle (the threshold). Pioneering investigators, notably Johann Friedrich Herbart and Gustav Theodor Fechner, adopted the metaphor of the threshold to characterize the transition point between unconsciousness and consciousness, an idiom subsequently translated into English scientific discourse as “auditory threshold.”
3. Pronunciation & Grammatical Form
In standard International Phonetic Alphabet (IPA) notation, the phrase is transcribed as: British English /ˈɔː.dɪ.tər.i ˈθrɛʃ.həʊld/ and American English /ˈɑː.də.tɔːr.i ˈθrɛʃ.hoʊld/.
Grammatically, “auditory threshold” functions as a countable noun phrase. It is regularly employed in both singular and plural forms (e.g., “the listener’s auditory threshold was elevated,” or “auditory thresholds vary systematically across the frequency spectrum”). It is frequently modified by attributive adjectives to denote specific operational conditions, yielding specialized nominal compounds such as absolute auditory threshold, masked auditory threshold, differential auditory threshold, and binaural auditory threshold.
4. Detailed Conceptual Explanation
The concept of the auditory threshold represents a core pillar of psychoacoustics, bridging the objective physics of sound waves with the subjective psychology of sensory perception. Sound travels through an elastic medium as mechanical longitudinal waves of compression and rarefaction. When these pressure fluctuations strike the tympanic membrane, they initiate a cascade of biomechanical events: the three middle ear ossicles (malleus, incus, and stapes) amplify and transfer this mechanical energy to the oval window of the fluid-filled cochlea. Inside the cochlea, basilar membrane displacement triggers the shearing of inner hair cell stereocilia, opening mechanically gated ion channels that depolarize the receptors and generate action potentials along the eighth cranial nerve.
The human ear does not exhibit uniform sensitivity across all frequencies. The absolute auditory threshold forms a distinct U-shaped curve across the standard audible frequency spectrum (nominally 20 Hz to 20,000 Hz). Human audition demonstrates its greatest sensitivity between 2,000 Hz and 5,000 Hz, a range precisely corresponding to the acoustic resonances of the external auditory canal and the middle ear transfer function, as well as the critical frequency bands of human speech. At these optimal frequencies, the auditory threshold is so sensitive that the tympanic membrane is displaced by distances smaller than the diameter of a hydrogen atom. At extreme low frequencies (below 100 Hz) and extreme high frequencies (above 10,000 Hz), the sound pressure level required for detection rises dramatically.
In experimental and clinical audiology, two foundational physical measurement paradigms establish the threshold: Minimum Audible Field (MAF) and Minimum Audible Pressure (MAP). MAF refers to the auditory threshold measured under free-field conditions where sounds are delivered through calibrated loudspeakers situated at a specified distance from the listener, thereby incorporating the natural acoustic amplification provided by the head, pinna, and torso. In contrast, MAP measures the threshold using calibrated earphones or insert receivers, isolating the ear and measuring the sound pressure level generated directly within the external ear canal. Consequently, MAF thresholds are systematically lower (representing greater sensitivity by 6 to 10 dB) than MAP thresholds due to binaural summation and the natural acoustic gain of the human head and outer ear.
Crucially, an individual’s auditory threshold is neither static nor purely deterministic. Moment-to-moment physiological fluctuations—such as cardiovascular pulsation, middle ear muscle contractions, intrinsic neural firing rates, and spontaneous mechanical emissions from outer hair cells—create a fluctuating internal noise floor. Therefore, psychoacousticians conceptualize the threshold as a statistical probability density function rather than an impenetrable physical wall. A tone presented at the nominal threshold level will elicit detection in roughly half of presentations, with detection likelihood rising monotonically as a function of stimulus intensity along a classic sigmoidal psychometric function.
5. Historical Development
The systematic exploration of the auditory threshold began in the mid-nineteenth century with the formalization of psychophysics. In 1860, German physicist and philosopher Gustav Theodor Fechner published his seminal work, Elemente der Psychophysik, expanding upon observations made by physiologist Ernst Heinrich Weber. Fechner formalized the mathematical and experimental methodology for quantifying the relationship between physical stimulus energy and conscious sensation, introducing the classical psychophysical methods—the method of limits, the method of constant stimuli, and the method of adjustment—to measure sensory thresholds rigorously.
During the late nineteenth and early twentieth centuries, the study of auditory thresholds transformed from qualitative physiological philosophy into an exact quantitative science. Hermann von Helmholtz, in his landmark 1863 treatise Die Lehre von den Tonempfindungen als physiologische Grundlage für die Theorie der Musik (On the Sensations of Tone), elucidated the resonance properties of the cochlea and laid the theoretical groundwork for understanding frequency-specific hearing thresholds.
The advent of electronic amplification and telecommunications in the 1920s and 1930s catalyzed unprecedented advances in threshold standardization. Researchers at Bell Telephone Laboratories, driven by the engineering imperative to optimize telephone transmission lines, conducted large-scale normative studies. In 1933, Harvey Fletcher and Wilden A. Munson published their definitive investigation establishing equal-loudness contours, systematically demonstrating how the absolute auditory threshold varies across frequencies and establishing the standard baseline for normal human audition. Subsequent refinements by D. W. Robinson and R. S. Dadson in 1956 formed the basis for international standards adopted by the International Organization for Standardization (ISO 226).
Simultaneously, Hungarian biophysicist Georg von Békésy developed micro-dissection and stroboscopic illumination techniques to observe basilar membrane movement in human cadaveric temporal bones. Von Békésy demonstrated that acoustic frequencies are mapped tonotopically along the basilar membrane via traveling waves, a discovery for which he received the 1961 Nobel Prize in Physiology or Medicine. His research provided the exact physical and mechanical mechanisms explaining why auditory thresholds are exquisitely frequency-dependent.
6. Theoretical Foundations
The theoretical framing of the auditory threshold has evolved through three primary conceptual models over the past century and a half: Classical Threshold Theory, Signal Detection Theory, and Modern Auditory Neuroscience.
Classical Threshold Theory: Postulated by early psychophysicists, this model assumed the existence of an absolute, biological barrier (the “all-or-none” sensory limen). Below this threshold, sensory events fail to activate neural mechanisms; above it, sensations inevitably reach consciousness. Deviations from an ideal step-function were attributed to extraneous “experimental error” or temporary lapses in attention. While computationally straightforward, classical threshold theory failed to account for listener bias, motivation, and false alarm rates.
Signal Detection Theory (SDT): Formulated in the mid-twentieth century by David M. Green and John A. Swets (1966), SDT fundamentally revolutionized sensory science by dismantling the classical concept of a fixed threshold. SDT posits that any auditory detection task occurs against a backdrop of continuous sensory noise (both external environmental noise and internal neurobiological noise). The listener’s sensory system produces an internal response whose magnitude varies continuously. Consequently, detecting an acoustic signal is bifurcated into two independent components: sensitivity (quantified as the discriminability index, d’), which reflects the true physiological capacity of the auditory system to separate signal from noise, and the response criterion (denoted as beta, β, or c), which reflects the psychological bias, motivation, or expectancy of the observer. Within SDT, there is no single fixed threshold; rather, performance reflects an optimal decision rule applied to a probabilistic continuum.
Neurobiological and Coding Theories: Contemporary neurobiology explains auditory thresholds through the physiology of hair cells and neural firing statistics. At threshold intensities, the motion of the basilar membrane is actively amplified by outer hair cells acting as a local mechanical amplifier (the cochlear amplifier). When outer hair cells lose functionality, auditory thresholds elevate by approximately 40 to 60 decibels. At the neural level, threshold detection requires that the firing rate of primary auditory nerve fibers significantly exceeds their baseline spontaneous discharge rate, or that a population of phase-locked neurons achieves coherent temporal synchronization across the auditory brainstem pathways.
7. Key Components, Types & Dimensions
Auditory thresholds are classified across multiple theoretical dimensions and operational criteria:
- Absolute Threshold of Hearing (ATH): The lowest sound pressure level at which an acoustic pure tone can be perceived in total silence.
- Difference Threshold (Difference Limen / Just Noticeable Difference – JND): The minimal physical change in frequency (Δf), intensity (ΔI), or phase necessary for a listener to perceive that two sounds are distinct. For mid-frequency sounds at moderate intensities, humans can detect intensity changes as fine as 0.5 to 1.0 dB and frequency changes as narrow as 0.2 to 0.3 percent.
- Masked Threshold: The elevated sound pressure level at which a target signal becomes detectable when presented concurrently with, immediately before (backward masking), or immediately after (forward masking) a competing interfering sound or noise band.
- Threshold of Discomfort / Uncomfortable Loudness Level (UCL): The upper boundary of hearing, typically occurring between 100 and 120 dB SPL, where sound transitions from being uncomfortably loud to painful, risking immediate mechanical damage to the auditory epithelium.
- Binaural vs. Monaural Thresholds: The auditory threshold measured when both ears listen simultaneously versus when a single ear is tested. Binaural hearing confers a physiological advantage known as “binaural summation at threshold,” lowering the detection threshold by approximately 3 dB relative to monaural listening.
- Temporary Threshold Shift (TTS): A reversible elevation in auditory threshold following sustained or intense exposure to acoustic trauma, reflecting temporary metabolic exhaustion of cochlear hair cells and support structures.
- Permanent Threshold Shift (PTS): An irreversible elevation in auditory threshold caused by structural loss of hair cells, auditory nerve synapses, or stria vascularis degeneration due to aging, chronic noise toxicity, or ototoxic pharmacological agents.
8. Examples & Illustrative Cases
To grasp the practical operation of auditory thresholds, consider three characteristic real-world scenarios across the lifespan and across clinical pathology:
Case 1: The Healthy Young Adult Baseline: A healthy 18-year-old undergoing standard pure-tone audiometry inside a sound-attenuated booth reveals thresholds between -5 and 5 dB Hearing Level (HL) across all octave frequencies from 250 Hz to 8,000 Hz. In quiet environments, this individual can readily detect extremely faint sounds, such as the gentle rustling of leaves at a distance (approximately 15 dB SPL) or a quiet whisper at two meters (approximately 20 to 25 dB SPL). At 3,000 Hz, where auditory canal resonance peaks, their threshold approaches 0 dB SPL, representing an exquisitely tuned mechanical system.
Case 2: Industrial Noise-Induced Threshold Shift: A 45-year-old factory machinist with 20 years of unprotected exposure to heavy stamping machinery presents with communication difficulties. Audiometric evaluation reveals normal hearing thresholds (10 dB HL) at 250 Hz, 500 Hz, and 1,000 Hz, but demonstrates a precipitous “notch” at 4,000 Hz, where the threshold is elevated to 65 dB HL. While the individual can hear low-pitched environmental noises and detect that someone is speaking, their elevated threshold in the high-frequency spectrum obliterates voiceless consonant sounds (such as /s/, /f/, /t/, and /th/), severely impairing speech intelligibility.
Case 3: Age-Related Threshold Elevation (Presbycusis): An 82-year-old grandmother experiences progressive difficulty conversing in crowded family gatherings. Her audiogram indicates a bilateral, symmetrical, sloping threshold elevation that begins moderately at 1,000 Hz (35 dB HL) and worsens progressively at 2,000 Hz (50 dB HL), 4,000 Hz (70 dB HL), and 8,000 Hz (85 dB HL). Environmental acoustic cues that once comfortably crossed her sensory threshold—such as birdsong or the chime of a microwave oven—now fall entirely beneath her absolute limit of perception.
9. Measurement & Assessment
Measuring auditory thresholds requires meticulous control over acoustic stimuli, environmental ambient noise levels, and psychological testing procedures. Measurement paradigms are divided into subjective (behavioral) and objective (electrophysiological) methodologies.
Behavioral Audiometry: The gold standard in clinical settings is pure-tone audiometry, administered using a calibrated audiometer and specialized transducers (supra-aural earphones, insert earphones, or bone-conduction oscillators). The standard clinical paradigm follows the modified Hughson-Westlake procedure, an ascending-descending staircase algorithm. In this protocol, the tester presents a pure tone; if the patient responds, the intensity decreases by 10 dB (“down 10”); if the patient fails to respond, the intensity increases by 5 dB (“up 5”). The auditory threshold is formally identified as the lowest intensity level at which a response is elicited in at least 50% of ascending trials (typically two out of three presentations at that level).
In experimental psychoacoustics, more rigorous psychophysical methods are employed: the Method of Constant Stimuli (presenting pre-determined randomized sound levels dozens of times to construct a complete psychometric curve) and adaptive tracking procedures (such as Levitt’s transformed up-down staircase method), which converge mathematically on predetermined points along the psychometric function (e.g., 70.7% or 79.4% detection accuracy).
Objective Electrophysiological Measures: When subjects cannot provide reliable behavioral feedback (such as neonates, pre-verbal infants, or uncooperative individuals), clinicians rely on objective neurophysiological correlates of the auditory threshold:
- Auditory Brainstem Response (ABR): Surface electrodes record synchronous electrophysiological potentials generated along the acoustic nerve and brainstem pathways within 10 milliseconds of a transient click or tone-burst stimulus. The lowest intensity that consistently evokes Wave V of the ABR corresponds closely to behavioral thresholds.
- Otoacoustic Emissions (OAEs): Sensitive miniature microphones placed in the ear canal measure low-level acoustic energy generated by the electromechanical motility of healthy outer hair cells in response to sound, providing an objective screening tool for cochlear threshold integrity.
- Auditory Steady-State Response (ASSR): Uses continuous, amplitude-modulated tones to evoke frequency-specific electrophysiological responses, automatedly analyzing brain wave synchronization across multiple frequencies simultaneously to predict audiometric thresholds.
10. Applications & Practical Significance
The auditory threshold holds deep significance across diverse scientific, clinical, and technological domains:
Clinical Audiology and Otology: Determining the absolute auditory threshold is the central diagnostic step for classifying the type (conductive, sensorineural, or mixed), degree (mild, moderate, severe, profound), and configuration (flat, sloping, notched) of hearing loss. Furthermore, precise threshold mapping directly governs the programming and fitting of electronic hearing aids and cochlear implants, ensuring that speech cues are amplified into the patient’s residual dynamic range without exceeding their threshold of discomfort.
Industrial Hygiene and Occupational Safety: Regulatory bodies worldwide, such as the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA), utilize auditory threshold shifts as clinical metrics to assess the hazardous nature of occupational soundscapes. Baseline and annual threshold monitoring protects workers by identifying early-stage temporary threshold shifts before they transition into irreversible permanent sensorineural damage.
Consumer Audio and Digital Media Compression: Modern lossy audio compression formats—most notably MP3, AAC, and Ogg Vorbis—rely entirely on mathematical models of human auditory thresholds and psychoacoustic masking. By calculating the absolute threshold of hearing and the dynamic masking thresholds of simultaneous musical tones, audio codecs systematically discard acoustic data that fall below the threshold of human audibility or are masked by louder neighboring frequencies, shrinking file sizes by over 80% without perceptible loss of fidelity to the human ear.
Architectural Acoustics and Noise Control: Architects, acoustic consultants, and environmental engineers design concert halls, classrooms, sound studios, and hospital wards around human auditory thresholds. Background noise criteria curves (such as NC or RC curves) ensure that heating, ventilation, and air conditioning (HVAC) systems do not generate ambient noise levels that mask important communicative auditory signals.
11. Research & Empirical Evidence
Extensive empirical research spanning more than a century has continually refined our understanding of auditory thresholds. The pioneering work of Fletcher and Munson (1933) established the first empirical equal-loudness contours, demonstrating that human hearing thresholds require up to 40 dB higher sound pressure at 100 Hz than at 1,000 Hz to reach audibility. These findings were critically revised and modernized by international laboratory consortiums, culminating in the standardized ISO 226:2003 equal-loudness contours, which established that the human ear is even less sensitive to low-frequency threshold stimuli than previously theorized.
Large epidemiological cohorts, including the landmark Framingham Heart Study and the National Health and Nutrition Examination Survey (NHANES) in the United States, have cataloged how auditory thresholds change across populations over time. These studies have consistently demonstrated that high-frequency auditory thresholds decline continuously from the third decade of life onward, with men exhibiting more severe and accelerated high-frequency threshold shifts than women, attributable to combined occupational exposures, systemic vascular health, and genetic susceptibility.
More recently, groundbreaking neuro-otological research led by Charles Liberman and Sharon Kujawa (2009) challenged the classical assumption that the auditory threshold represents the definitive index of auditory health. Their empirical animal and post-mortem human investigations demonstrated the phenomenon of “cochlear synaptopathy”—frequently termed hidden hearing loss. They revealed that noise trauma and aging can permanently destroy up to 50% of the synaptic connections between inner hair cells and auditory nerve fibers without causing any measurable elevation in the standard pure-tone auditory threshold. This research proved that while standard audiometric thresholds evaluate outer hair cell integrity and minimum sensitivity, they do not capture complex neural processing deficits in noisy environments.
12. Cultural & Cross-Cultural Considerations
Although the anatomical architecture of the peripheral human ear is biologically universal, ecological, cultural, and environmental settings substantially shape auditory threshold preservation and perceptual processing across the globe.
A classic series of anthropological and epidemiological investigations conducted by Samuel Rosen and colleagues in the 1960s studied the Mabaan tribe, an isolated, pre-industrial population living in the acoustically quiet savanna of southeast Sudan. The researchers discovered that elderly Mabaan individuals exhibited remarkably preserved auditory thresholds at high frequencies (4,000 to 12,000 Hz) that were far superior to age-matched cohorts in industrialized North American and European cities. While initially attributed to genetic differences, subsequent research emphasized the absence of intense industrial noise pollution, lower systemic blood pressure, and low-fat diets as decisive environmental factors that prevent premature threshold elevation.
Cultural and linguistic backgrounds also influence differential auditory thresholds for complex sounds. Native speakers of tonal languages (such as Mandarin Chinese, Cantonese, and Vietnamese) frequently display significantly finer frequency difference limens (difference thresholds) than native speakers of non-tonal languages (such as English or Spanish). Because lexical meaning in tonal languages hinges on pitch contours, continuous linguistic immersion sharpens auditory cortex plasticity, resulting in heightened behavioral and neural sensitivity to microscopic acoustic pitch fluctuations.
Furthermore, access to health literacy, occupational protective equipment, and healthcare infrastructure creates profound disparities in auditory threshold preservation across different socioeconomic groups and developing nations. In developing economies with limited occupational safety regulation, young industrial and agricultural laborers frequently develop severe, premature threshold shifts that remain undiagnosed and unmanaged due to a dearth of basic audiological testing resources.
13. Criticisms, Debates & Limitations
Despite its ubiquitous clinical utility, the construct of the auditory threshold faces important scientific criticisms and operational limitations:
The Fallacy of the Fixed Sensory Limen: As highlighted by Signal Detection Theory, treating the auditory threshold as an invariant, physiological property of the ear is theoretically flawed. An individual’s apparent behavioral threshold shifts according to response bias, instruction set, economic reward, state of fatigue, emotional stress, and vigilance. A cautious observer will exhibit an artificially elevated threshold, whereas an eager observer will display an artificially lower threshold accompanied by high false-alarm rates.
The Clinical Invisibility of “Hidden Hearing Loss”: The reliance on pure-tone auditory thresholds as the primary clinical indicator of auditory wellness has drawn sharp debate. Because standard pure-tone audiometry evaluates hearing in absolute silence, patients with significant cochlear synaptopathy or early auditory processing disorders routinely present with completely “normal” auditory thresholds (0 to 20 dB HL), yet struggle profoundly to understand speech in moderately reverberant or noisy social settings. Consequently, critics argue that relying exclusively on threshold testing leads to underdiagnosis and systemic dismissal of legitimate auditory complaints.
Acoustic Simplicity vs. Ecological Validity: Pure sinusoidal tones presented in clinical testing bear almost no resemblance to the acoustic complexity of natural soundscapes. Natural sounds are spectrally rich, temporally modulated, and dynamically unpredictable. Measuring absolute detection thresholds for isolated pure tones reveals very little about how the auditory brainstem and cortex integrate speech, localize sounds, or segregate simultaneous acoustic streams.
Test-Retest Reliability and Calibration Discrepancies: In conventional pure-tone testing, intra-subject test-retest threshold variability of ±5 dB is considered clinically standard. This variance stems from slight differences in earphone placement, ear canal collapse under headphone pressure, standing waves in the ear canal during high-frequency stimulation (above 4,000 Hz), and natural fluctuations in ambient room noise.
14. Related Terms & Distinctions
To avoid conceptual ambiguity, the auditory threshold must be systematically differentiated from closely related acoustic and psychoacoustic constructs:
- Auditory Threshold vs. Sensation Level (SL): The auditory threshold represents the absolute physical level of sound required for detection (referenced to 0 dB HL or dB SPL). By contrast, Sensation Level designates the intensity of a sound in decibels above an individual’s specific auditory threshold (e.g., a tone presented at 30 dB SL to a person with a 20 dB threshold is presented at an absolute physical level of 50 dB).
- Auditory Threshold vs. Loudness: Threshold refers strictly to audibility (the borderline between hearing and not hearing), whereas loudness is the subjective psychological magnitude of sound intensity perceived well above the threshold. Two sounds presented at their respective threshold levels share identical detection probability (audibility), but do not necessarily share identical loudness growth trajectories once intensity increases.
- Auditory Threshold vs. Speech Reception Threshold (SRT): While the pure-tone auditory threshold measures the detection of simple single frequencies, the Speech Reception Threshold (or Speech Recognition Threshold) identifies the lowest intensity level at which an individual can correctly identify and repeat complex speech materials, such as spondaic words, 50% of the time.
- Auditory Threshold vs. Hyperacusis: An elevated auditory threshold indicates a decrease in hearing sensitivity (hearing loss). Hyperacusis, conversely, represents a pathology wherein everyday moderate sounds are perceived as excruciatingly loud or painful, despite the patient often exhibiting normal or even heightened absolute auditory thresholds.
- Auditory Threshold vs. Auditory Recruitment: Recruitment is an abnormal growth of loudness that frequently accompanies sensorineural hearing loss. Although an individual’s auditory threshold is significantly elevated (requiring louder sounds to initiate detection), sounds just slightly above that threshold quickly become as loud as they would to a person with normal hearing, compressing their functional dynamic range.
15. Summary / Key Takeaways
The auditory threshold represents the fundamental sensory gateway of human audition, marking the transition from physical acoustic energy to conscious perception. Governed by the mechanical architecture of the outer and middle ear, the active biological amplification of outer hair cells, and the neural synchronization of the auditory pathway, the threshold exhibits exquisite frequency tuning, peaking between 2,000 and 5,000 Hz. Standardized through historical psychophysics and refined by modern Signal Detection Theory, the threshold is recognized today not as a rigid biological wall, but as a probabilistic decision boundary continually influenced by internal neural noise and cognitive factors.
From clinical diagnostics and hearing aid engineering to industrial noise standards and perceptual audio algorithms, measuring and preserving auditory thresholds remains essential across modern society. While standard pure-tone audiometry remains the international benchmark for quantifying sensory sensitivity, emerging discoveries surrounding hidden hearing loss and cochlear synaptopathy emphasize that complete auditory health extends far beyond the traditional threshold of audibility.
References
- American National Standards Institute. (2018). Specifications for audiometers (ANSI/ASA S3.6-2018). American National Standards Institute.
- Fechner, G. T. (1860). Elemente der Psychophysik. Breitkopf und Härtel.
- Fletcher, H., & Munson, W. A. (1933). Loudness, its definition, measurement and calculation. Journal of the Acoustical Society of America, 5(2), 82–108. https://doi.org/10.1121/1.1915637
- Green, D. M., & Swets, J. A. (1966). Signal detection theory and psychophysics. John Wiley & Sons.
- Helmholtz, H. von. (1863). Die Lehre von den Tonempfindungen als physiologische Grundlage für die Theorie der Musik. Friedrich Vieweg und Sohn.
- International Organization for Standardization. (2003). Acoustics — Normal equal-loudness-level contours (ISO Standard No. 226:2003). https://www.iso.org/standard/34222.html
- Kujawa, S. G., & Liberman, M. C. (2009). Adding insult to injury: Cochlear nerve degeneration after “temporary” noise-induced hearing loss. The Journal of Neuroscience, 29(45), 14077–14085. https://doi.org/10.1523/JNEUROSCI.2845-09.2009
- Moore, B. C. J. (2012). An introduction to the psychology of hearing (6th ed.). Brill.
- von Békésy, G. (1960). Experiments in hearing (E. G. Wever, Trans. & Ed.). McGraw-Hill.