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Questions and Answers
What range defines normal hearing for adults?
What range defines normal hearing for adults?
What characterizes mild hearing loss?
What characterizes mild hearing loss?
In what situation is AC masking needed?
In what situation is AC masking needed?
What defines a profound hearing loss?
What defines a profound hearing loss?
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Which type of hearing loss is indicated by a significant air-bone gap?
Which type of hearing loss is indicated by a significant air-bone gap?
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What initial threshold is used in the Hughson-Westlake procedure?
What initial threshold is used in the Hughson-Westlake procedure?
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What classification applies to hearing with normal bone conduction and poor air conduction?
What classification applies to hearing with normal bone conduction and poor air conduction?
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What does the speech banana represent on an audiogram?
What does the speech banana represent on an audiogram?
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What is the initial component of a complete audiological evaluation?
What is the initial component of a complete audiological evaluation?
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Which type of testing primarily assesses middle ear function?
Which type of testing primarily assesses middle ear function?
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During the Pure Tone Testing Procedure, how is the hearing threshold determined according to the Hughson-Westlake Procedure?
During the Pure Tone Testing Procedure, how is the hearing threshold determined according to the Hughson-Westlake Procedure?
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What does Air Conduction (AC) thresholds indicate in terms of hearing loss?
What does Air Conduction (AC) thresholds indicate in terms of hearing loss?
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What does the Pure Tone Average (PTA) indicate?
What does the Pure Tone Average (PTA) indicate?
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Which frequency range is used during Bone Conduction (BC) testing?
Which frequency range is used during Bone Conduction (BC) testing?
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Which frequencies are used to calculate the Pure Tone Average (PTA)?
Which frequencies are used to calculate the Pure Tone Average (PTA)?
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When recording results in Air Conduction Audiometry, how is the right ear threshold represented?
When recording results in Air Conduction Audiometry, how is the right ear threshold represented?
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What component of an audiogram indicates the pitch of sound?
What component of an audiogram indicates the pitch of sound?
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When is masking necessary during Bone Conduction testing?
When is masking necessary during Bone Conduction testing?
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Which factor does NOT affect hearing thresholds during Pure Tone Audiometry?
Which factor does NOT affect hearing thresholds during Pure Tone Audiometry?
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What minimum Interaural Attenuation (IA) value is required for Air Conduction testing with insert earphones?
What minimum Interaural Attenuation (IA) value is required for Air Conduction testing with insert earphones?
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What distinguishes Conductive Hearing Loss (HL) from Sensorineural HL as per the Air-Bone Gap (ABG)?
What distinguishes Conductive Hearing Loss (HL) from Sensorineural HL as per the Air-Bone Gap (ABG)?
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Which description accurately reflects a 'mixed hearing loss' as per the provided information?
Which description accurately reflects a 'mixed hearing loss' as per the provided information?
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What does cross-hearing refer to in the context of audiometric testing?
What does cross-hearing refer to in the context of audiometric testing?
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What is the typical range for a mild degree of hearing loss?
What is the typical range for a mild degree of hearing loss?
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Study Notes
Pathways of Sound
- Air Conduction (AC): Sound travels through the outer ear to the inner ear.
- Bone Conduction (BC): Sound bypasses the outer and middle ear and vibrates directly through the skull.
- Air-Bone Gap (ABG): The difference between AC and BC thresholds. A significant ABG (greater than 12 dB) indicates a conductive hearing loss.
Air and Bone Conduction Testing
- Air Conduction (AC) Testing: Measures AC thresholds using supra-aural or insert earphones.
- Bone Conduction (BC) Testing: Measures BC thresholds using a bone vibrator. There is no interaural attenuation (IA) for BC, meaning both ears can respond.
Audiogram Interpretation
- Conductive Hearing Loss (CHL): Normal BC, but AC shows a significant ABG.
- Sensorineural Hearing Loss (SNHL): BC thresholds are not within normal limits, and there is no significant ABG.
- Mixed Hearing Loss: BC thresholds are not within normal limits, and there is a significant ABG.
Masking in BC Testing
- Purpose: To prevent the non-test ear from responding to the test signal.
- When to Mask: When there are significant ABGs at any frequencies.
- Procedure: Deliver noise to the non-test ear to isolate responses from the test ear.
Crossover and Cross-Hearing
- Crossover: Sound presented to the test ear can reach the non-test ear.
- Cross-Hearing: The crossover sound is audible in the non-test ear.
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Interaural Attenuation (IA): The amount of sound reduction that occurs when sound crosses from one ear to the other.
- AC: Supra-aural earphones have 40 dB IA; Insert earphones have 70 dB IA.
- BC: Has virtually no IA.
Degree of Hearing Loss
- Mild: 26-40 dB HL
- Moderate: 41-55 dB HL
- Moderately Severe: 56-70 dB HL
- Severe: 71-90 dB HL
- Profound: >90 dB HL
Basic Hierarchy of Auditory Skills Development
- Detection: Awareness of sound
- Discrimination: Recognizing if two sounds differ.
- Identification: Associating meaning with a sound.
- Comprehension: Understanding words, phrases, and sentences, and responding to directions.
Complete Audiological Evaluation
- Case History: Information about the patient's complaints, symptoms, medical and rehabilitation history.
- Otoscopy: Exam of the ear canal and tympanic membrane.
- Immittance Testing: Assessment of middle ear function.
- Degree and Type of Hearing Loss: Identification of the severity and type of hearing loss (conductive, sensorineural, or mixed).
- Speech Testing: Checking speech perception.
- Counseling & Recommendations: Sharing results and next steps.
Pure Tone Audiometry
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Factors Affecting Hearing Thresholds:
- Methodological: Test environment and instructions.
- Physiological: Ear and auditory pathway health.
- Psychological: Patient's alertness and responses.
- Physical: Earphone fit and equipment accuracy.
- Environmental: Background noise.
Pure Tone Testing Procedure
- Instructions: The patient is instructed to respond when they hear a tone.
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Setup:
- Seating: Patient can sit in the front, back, or side.
- Earphones: Standard or insert earphones are utilized.
- Response Modes: The patient can respond by hand, verbally, or pressing a button.
- Testing Frequencies: 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, and 8 kHz are tested.
- Hughson-Westlake Procedure: Uses a descending/ascending approach to determine the hearing threshold.
Air Conduction Audiometry
- Purpose: Determines the degree of hearing loss affecting the entire auditory pathway.
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Testing Process:
- Start at 1 kHz, 30 dB HL: Adjust the intensity based on the patient's response.
- Establish thresholds: Determine the thresholds for each ear.
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Recording results:
- Right ear (AC) threshold: Marked as "O"
- Left ear (AC) threshold: Marked as "X"
- Pure Tone Average (PTA): Calculated by averaging the 500 Hz, 1 kHz, and 2 kHz thresholds.
- PTA Significance: Indicates the degree of hearing loss and potential communication impact.
The Audiogram
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Axes:
- Frequency (Pitch): Vertical axis from low to high pitch (125 Hz to 8 kHz).
- Intensity (Loudness): Horizontal axis from soft to loud (0 dB HL to 120 dB HL).
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Thresholds:
- The lowest sound level a person can hear at each frequency.
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Normal Hearing:
- Adults: -10 dB HL to 25 dB HL
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Children: -10 dB HL to 15 dB HL
- Slight/Minimal Loss: 16-25 dB HL
- Speech Banana: An area on the audiogram representing the frequencies and intensities typical for human speech sounds.
Degree of Hearing Loss
- Mild: 26-40 dB HL - Adults may have difficulty understanding soft speech; children may have language learning difficulties.
- Moderate: 41-55 dB HL - Hearing aids are often beneficial; visual cues may be necessary.
- Moderately Severe: 56-70 dB HL - Speech sounds at normal conversation levels are inaudible.
- Severe: 71-90 dB HL - Difficulty hearing loud speech; hearing aids or implants may help.
- Profound: >90 dB HL - Limited benefit from hearing aids; cochlear implants may be considered.
Types of Hearing Loss
- Conductive Hearing Loss: Affecting the outer or middle ear. AC thresholds are worse than BC thresholds.
- Sensorineural Hearing Loss (SNHL): Inner ear or auditory nerve damage. Similar AC and BC thresholds.
- Mixed Hearing Loss: Both conductive and sensorineural components; shown by significant differences between AC and BC.
Masking in AC and BC Testing
- AC Masking: Needed if the AC threshold in the test ear is louder than the NTE's BC threshold by 40 dB (supra-aural) or 70 dB (inserts).
- BC Masking: Necessary for cases of AC masking or when there is a significant ABG.
Hughson-Westlake Procedure
- Start at 1 kHz and 30 dB HL.
- Decrease by 10 dB if they hear it; increase by 5 dB if they don't.
- Repeat until threshold (softest audible level) is found.
Speech Testing
- Checks speech perception at various loudness levels.
- Useful for evaluating real-world hearing abilities.
Interaural Attenuation (IA)
- The sound reduction as it crosses from the test ear to the non-test ear helps determine the need for masking.
- IA for Supra-aural Earphones: 40 dB
- IA for Insert Earphones: 70 dB
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Description
Explore the mechanisms of sound conduction in audiology, including air and bone conduction. This quiz covers air-bone gap implications and interpretation of audiograms in relation to different types of hearing loss. Test your understanding of these critical concepts in sound testing.
