Hearing threshold: The point at which you can just barely hear a sound 50% of the time. It’s the foundation of the audiogram, usually measured in Decibel (dB HL) to reflect loudness needed for detection. - Frequency (Hz): The pitch of a sound. Audiograms plot thresholds across frequencies, typically from low to high: 🎧 Frequencies that matter most for speech are the speech frequencies. - Intensity: The loudness level. Thresholds are often plotted from soft (near 0 dB HL) to louder sounds to see how well you detect tones at various intensities. - Hearing level: The reference used on the audiogram. A normal hearing person has thresholds within a standard range, while elevated thresholds indicate some degree of hearing loss. Key measurements and symbols you’ll see - Pure tone: The basic beep used in testing, across multiple frequencies. - Air conduction vs. Bone conduction: Air conduction tests sound through the ear canal; bone conduction tests vibrations directly to the inner ear. Comparing the two helps distinguish types of loss. - Masking: When a sound presented to one ear could be heard by the other, masking noise is used to keep the non-test ear quiet. - Unmasked / Masked thresholds: The graph may show thresholds without masking (unmasked) and with masking (masked) when necessary. - Hearing Threshold Symbols: The specific marks on the audiogram legend indicate where thresholds lie for air and bone conduction. Types of hearing loss you might see reflected in the graph - Normal hearing: Thresholds within the typical range across frequencies. - Conductive hearing loss: Air conduction impaired, bone conduction near normal. - Sensorineural hearing loss: Both air and bone conduction show elevated thresholds, reflecting inner ear or neural pathway issues. - Mixed hearing loss: A combination of conductive and sensorineural findings (air conduction worse than bone conduction; both elevated). - Notation often highlights where the gap lies and whether masking was applied. Degree of hearing loss (how loud sounds have to be for detection) - Mild, Moderate, Moderately severe, Severe, Profound - The degree helps guide decisions about amplification, assistive devices, and communication strategies. Speech and performance measures that complement the audiogram - Speech audiometry breaks down how well you understand speech, not just hear it. - Speech Reception Threshold (SRT): The quietest level at which you can repeat or recognize words or phrases. - Speech Detection Threshold (SDT): The level at which you can detect speech sounds, even if you can’t understand them fully. - Word Recognition Score (WRS): How well you identify words at a comfortable listening level, a key gauge of real-world understanding. - Speech discrimination assesses how well speech is distinguished from noise, which can differ from pure-tone results. Audiogram configurations you might notice - Flat: Similar thresholds across frequencies—consistent loss. - Sloping: Better low frequencies, worse high frequencies—common in age-related (presbycusis) or noise-related losses. - Rising: Poor low frequencies with better high frequencies—rarer, seen in certain pediatric or medical conditions. - Notched: Drop at a particular frequency band (often around 3–6 kHz) while others are better. - Cookie-bite: Mid-frequency notch, with better lows and highs—classic in some hereditary conditions. Clinical terms and testing considerations - Masking noise: Used to prevent the non-tested ear from influencing results. - Interaural attenuation: The reduction of sound energy as it crosses from one ear to the other; a key concept for deciding when masking is needed. - Crossover: When signals intended for one ear are heard by the other, potentially confounding thresholds. - Reliability: The consistency of responses across repeated tests and conditions—critical for trusting the audiogram. Putting it together: a clinician’s workflow 1) Measure air conduction and bone conduction thresholds across a range of frequencies (low, mid, high). Note the Pure tone thresholds. 2) Decide if masking is required based on interaural attenuation and crossover risk. 3) Interpret the degree and type of hearing loss, using the Audiogram Configuration as a guide. 4) Add speech audiometry results (SRT, SDT, WRS) to assess functional communication. 5) Classify into Normal hearing, Mild to Profound loss, and determine the likely diagnosis (Conductive, Sensorineural, Mixed). 6) Communicate implications for everyday listening and potential interventions (hearing aids, cochlear implants, or other supports).