Manual Pure Tone Audiometric Procedures

Flashcards covering key terms and definitions from the lecture on Manual Pure Tone Audiometric Procedures, including general order of events, otoscopy, audiogram descriptors, and threshold determination.

Pure Tone Audiometry (General Order of Events)

Preliminary information/history, otoscopic inspection, listener instructions, earphone placement, and following test procedures.

Otoscopy

Visual inspection of the ear and ear canal to check the health and quality of the eardrum (e.g., spink, shiny, cone of light, absence of debris/pus, and no holes).

Tympanic Membrane (TM)

An 8-10 mm diameter membrane, approximately 0.1 mm thick, consisting of epidermal, fibrous, and membranous layers, which covers the middle ear space.

Tympanosclerosis

Calcified plaques occurring around the circumference of the Tympanic Membrane and/or the head of the malleolus, often related to hearing loss, especially when the ossicular chain is involved.

Cross-Check Principle

The practice of using multiple tests to corroborate findings and ensure the validity of a hypothesis regarding a patient's hearing.

Routine Audiologic Evaluation

A typical sequence of tests including preliminaries (interview, otoscopy, Weber & Rinne), audiometric evaluation (Air Conduction, SRT, Pure-Tone Thresholds, Speech Understanding, Bone Conduction), and immittance tests (Tympanometry, Acoustic Reflex Tests).

Tympanometry

A measure of several aspects of middle ear function, distinct from a hearing test.

Acoustic Reflex Tests

Measures middle ear, cochlear, and neural (VIIIth nerve and brainstem) function.

Pure Tone Audiometric Threshold Testing (Basic Steps)

Equipment readiness, patient preparation, and threshold determination.

AC Unmasked (symbols)

Right ear: O, Left ear: X (representing air conduction, assessing the entire auditory pathway).

AC Masked (symbols)

Right ear: triangle, Left ear: square (representing air conduction when the non-test ear is masked).

BC Unmasked (symbols)

Right ear:

BC Masked (symbols)

Right ear: [, Left ear: ] (representing bone conduction when the non-test ear is masked).

Audiogram Descriptors

Four classical ways to describe hearing depicted on an audiogram: degree, type, configuration, and symmetry of loss.

Pure Tone Audiometry

The most common test to estimate a person's threshold of audibility, recorded on an audiogram, which answers the question "how much hearing loss is there?".

Audiogram

A standard form used to record the threshold of audibility, marking the 'beginning' of what sounds a listener can hear.

Threshold of Hearing/Audibility

The least amount of amplitude of a signal a listener can hear 50% of the time (e.g., on 2 out of 3 trials), a statistical concept based on data across several trials.

Threshold Determination (Examiner Decisions)

The examiner's decisions during testing: which ear to test first (right vs. left), which modality (air vs. bone), and which frequency to start with.

Ear Selection Rule (Pure Tone Audiometry)

Per ASHA (2005), the better ear should be tested first, determined by patient history, fork tests, or previous test results.

Modality Selection Rule (Pure Tone Audiometry)

Air conduction testing is performed first. Bone conduction is typically done only if the patient's first test shows hearing loss to determine the type of loss.

Familiarization (Audiometry)

The process of introducing the task to the patient and familiarizing them with the sound, typically starting at 1000 Hz.

Initial Frequency Selection Rule (Pure Tone Audiometry)

ASHA (2005) recommends starting at 1000 Hz, then higher frequencies (2000, 4000, 8000 Hz), repeating 1000 Hz for intra-test reliability, then lower frequencies (500, 250 Hz).

Familiarization Phase (Threshold Search)

The initial stage of threshold determination where the patient is introduced to the task and the sound.

Measurement Phase (Threshold Determination)

The stage following familiarization, where the actual hearing threshold is sought.

ASHA (2005) Familiarization Phase Procedure

Start at 1000 Hz, 30 dB HL. If no response, increase to 50dB; if still no response, increase in 10 dB steps until a response is obtained.

ASHA (2005) Threshold Determination Phase

Uses an "ascending technique beginning with an inaudible signal" where the volume is gradually increased to find the threshold.

Up 5, Down 10 Procedure / Bracketing

The basic principle of threshold determination: increase 5 dB until a response ("up 5"), then decrease 10 dB until no response ("down 10"), for subsequent presentations.

Threshold (Audiometry Definition)

The lowest dB value at which a patient responded for 50% of the trials, occurring after increases ('up 5' moves), with a minimum of two responses required (ANSI 2004).

ASHA (2005) Threshold Determination (Five Features)

Tone duration 1-2 sec; varied inter-stimulus intervals (not shorter than tone); first presentation below expected threshold; succeeding presentation levels based on preceding response; threshold based on 50% response rate criterion.

Degree of Hearing Loss (Audiogram)

A descriptor indicating the extent of hearing loss or the amount of residual hearing.

Configuration of Hearing Loss (Audiogram)

A descriptor referring to the shape of the audiogram, indicating how hearing varies across different frequencies.

Type of Hearing Loss (Audiogram)

A descriptor classifying hearing loss as sensorineural, conductive, or mixed.

Symmetry of Hearing Loss (Audiogram)

A descriptor indicating whether the hearing loss values are equal or asymmetric between the two ears.

Information Not on a Single Audiogram

A single audiogram does not provide information on the time of onset, permanency, or progression of hearing loss, nor does it directly measure the ability to understand speech.

Normal Hearing (dB HL)

Hearing thresholds between -10 and 25 dB HL.

Mild Hearing Loss (dB HL)

Hearing thresholds between 26 and 40 dB HL.

Moderate Hearing Loss (dB HL)

Hearing thresholds between 41 and 55 dB HL.

Moderate-Severe Hearing Loss (dB HL)

Hearing thresholds between 56 and 70 dB HL.

Severe Hearing Loss (dB HL)

Hearing thresholds between 71 and 90 dB HL.

Profound Hearing Loss (dB HL)

Hearing thresholds at 91 dB HL or greater.

Problems with 'Degree' Description (Audiogram)

Categorization words for degree of loss are not universally agreed upon, results often cross categories, and the degree of loss does not reliably predict the extent of an individual's hearing problems or speech understanding.