Aud exam 2 study

Audiometry Overview

Audiometry is the science concerned with evaluating hearing loss through various testing methods, including screening and diagnostic assessments.

Basic Notion of Hearing Tests

  • Testing approach:

    • Down 10, Up 5: Method to determine hearing sensitivity.

    • Two primary types:

      • Screening Tests:

        • Purpose: Pass/refer assessment.

        • Duration: Approximately 3 minutes.

      • Diagnostic Tests:

        • Purpose: Determines thresholds and provides a complete audiometric evaluation.

        • Duration: Approximately 20 minutes.

  • Key Role of Audiologists:

    • Explaining and discussing audiogram results with clients.

    • Use of color code: RED for right ear and BLUE for left ear.

Types of Testing

Behavioral Testing

  • Client’s task: Raise hand or push button upon hearing a tone or speech.

  • Limitations:

    • Clinician cannot control when the client raises their hand.

    • Potential for malingering (faking results).

Physiological Testing

  • Measures body’s responses to presented signals, requiring no active response from the client.

  • More objective than behavioral tests, as clients can’t fake this response.

Pure Tone Audiometry

  • Involves assessing both bone and air conduction thresholds.

Speech Audiometry

  • Assesses speech thresholds using speech instead of tones.

  • Uses Spondee Words: Two-syllable words with equal stress (e.g., hotdog, baseball).

Basic Concepts

  • Threshold: The minimum level of sound that can be heard.

  • Stimuli: Different forms of input used in assessments.

    • Pure Tone: Single frequency tone ranging from 250 to 8000 Hz.

    • Speech: Spondees with equal stress.

  • Intensity Level: The loudness of the stimuli presented.

Equipment for Audiometry

Audiometer Types

  • Console Audiometer:

    • Designed for use in sound treated booths.

    • Features two channels for masking.

  • Screening Audiometer:

    • Simplified controls; intensity relates to dB HL.

    • Normally off position unless activated by pressing a button.

Important Equipment Features

  • Talk Forward Button: Communicates directly with clients and overrides other sounds.

  • Stimulus Presentation and Control: Knobs for adjusting intensity and choosing transducers (air, bone, speaker).

  • Transducer Types:

    • Circum-aural headphones, Supra-aural headphones, Bone oscillator, and loudspeakers.

  • Calibration: Necessary for accurate measurements; must be performed annually and checked daily.

Audiometry Variables

Calibration and Accuracy

  • Importance of regular calibration to ensure equipment accuracy.

  • Types of calibration:

    • Acoustic Output: Ensuring the equipment matches output with settings.

    • Biological Calibration: Test with a known hearing individual for basic accuracy.

    • Ambient Noise Conditions: Should be under ANSI-1989 standard for optimal results.

Audiological Evaluations

  • Case History: First step to understanding a client’s background.

    • Collect information from referrals about medical history and symptoms.

  • Otoscopic Examination: Inspecting the external ear canal and tympanic membrane.

Main Purpose of Hearing Evaluation

  • Define the nature and extent of hearing loss, determining type and degree.

Referral Sources

  • Different individuals may refer clients:

    • Self-referrals, physicians, teachers, spouses, children, allied health professionals, etc.

Types of Hearing Loss

  • Categories:

    • Conductive, Sensorineural, Mixed, Central.

Air-Bone Gaps

  • Indicates potential conductive issues in the hearing pathway.

  • Bone conduction testing reveals a person's best potential for hearing.

Masking in Audiometry

Reasons for Masking

  • Used when there is a risk of crossover during testing, especially to obtain ear-specific information for unilateral or asymmetric hearing loss.

  • Plateau Method:

    • Identifies optimal level for masking: 50 without mask, then escalating noise levels to see if responses change within a plateau, confirming validity of results.

Final Notes

  • Regardless of the test, individual characteristics such as age and cognitive function can impact results.

  • Show confidence and thoroughness in the testing and evaluation process, while ensuring a supportive environment for the client.