Audiological Procedures Notes

Purpose of Hearing Screening Programs

Separate those who most likely do not have the disorder from those who might have the disorder

Target Populations for Hearing Screening Programs

Newborns and young children
Those who are unable or reluctant to obtain the services they need

Elderly may ignore their problems or think it is just a normal aging process that they cannot do anything about.

Employees at risk for NIHL

Criteria for Screening Populations

Do not show or act upon symptoms of disorder, good chance of finding those with disorder, disorder is important enough to identify in larger population

Reliability

Repeats what is told at first

Validity

The test is capable of finding what the clinician is looking for

Universal Screening

Screening of a large group, disorder must be highly significant, need a cost-effective way of managing personnel and equipment

Targeted Screening

A way of making the screening more cost effective is to only screen a subgroup from the larger population that is at higher risk for the disorder

UNHS

Universal Newborn Hearing Screening

EHDI Program

Early Hearing Detection and Intervention

UNHS - EHDI Goal

Identify permanent and significant hearing loss

OAE

Otoacoustic Emissions, has built-in algorithm to determine if infant meets the criteria for a “pass”

AABR

Automated Auditory Brainstem Response, quick attaching disposable electrodes with a single pre-set click stimulus level (30-40 dB nHL), software algorithm to determine if waveform matches a “pass” waveform

1-3-6 Rule

1 Month - Screened, 3 Months - Tested for Loss/No Loss, 6 Months - Aural Rehabilitation to produce spoken language

Risk Factors for Congenital and Delayed Onset Hearing Loss

Caregiver concern regarding speech, language, and/or hearing development

Family history of permanent childhood HL

Time spent in NICU (>5 days) 

Ototoxic medications/chemotherapy

In utero or postnatal infections associated with hearing loss

Craniofacial anomalies

Syndromes associated with congenital, progressive, or late-onset hearing loss

Head trauma

School-Age Hearing Screening Guidelines

Hearing screening recommended annually for children in preschool through 3rd grade, 7th grade, and 11th grade. Use portable audiometers, tymp machine, and trained nurse with students supervised by an audiologist

School-Age Hearing Procedures

Otoscopy, Tympanometry, Pure-Tone Testing (1k, 2k, and 4k frequencies, 20 dB)

School-Age Children Hearing Screening Results/Follow Up

Pass

Recommended cerumen removal by pediatrician

Pass pure tone screening, fail tympanometry in one/both ears

Fail pure tone screening, pass tympanometry

Fail both pure tone screening and tympanometry

CNT (Could Not Test) due to behavioral issues or young age

Screening Outcomes and Efficacy

Purpose: Separate those who might have a disorder and those who might not have a disorder

Assumes a “gold standard” exists to validate screening results

Pure-tone audiometry

ABR if 0-6 months (> 6 month pure tones via VRA)

True Positive

A hit

True Negative

True normal

False Positive

Inaccurate or error response

False Negative

A miss

Sensitivity

How well the test correctly identifies the disorder, calculated as TP/(TP+FN)

Specificity

How well the test correctly identifies those without the disorder, TN/(TN+FP)

Positive Predictive Value

Level of confidence you have in the true positive outcome, TP/(TP+FP)

Negative Predictive Value

Level of confidence you have in the true negative outcome, TN/(TN+FN)

HA (Hearing Aid) Selection and Fitting Steps

Assessment, Treatment Planning, Selection, Verification, Orientation, Validation

Assessment

Candidacy: Look at audiogram, Patient’s mindset/ownership re: his/her hearing loss, questionnaires/self-assessment inventories

Treatment Planning

Share results with family, environments they need the most help in? Do they feel the need for hearing aids?

Selection

Determine style, size, technology level, cost of hearing aids

Verification

Sound quality check, is the HA functioning according to manufacturer specs?

Orientation

explain use/care/maintenance of HA, discuss realistic expectations, is there a need for an aural rehabilitation program?

Validation

Evaluate HA benefit and satisfaction

Noah

Plugging in required software

Common Fitting Methods

NAL-NL3, DSLv5.0a

Basic HA Components

Microphone, Analog to Digital Conversion, Amplifier, Digital to Analog Conversion, Receiver
Battery, Volume Control, Telecoil

Multiple Memory Programs

Specific settings can be saved into “programs”

Multiple Channels

Frequency specific channels; Gain can be adjusted independently in each channel

Automatic Gain Control for Output

Need to limit maximum output of sound; The HA will not allow a sound to be amplified more than what you specify to go into the client’s ear; AGC is a type of compression

Automatic Gain Control for Input

This is used when soft sounds need to be amplified more than loud sounds; This type of compression often called WDRC (wide dynamic range compression); Requires increased gain for soft sounds, reduced gain for moderate sounds, and further reduction for louder sounds

Automatic Digital Noise Reduction

Reduce gain in frequencies when it detects a steady state noise; Helps listening comfort and decreases listener fatigue

Adaptive Feedback Reduction

Feedback - Sound that has been amplified and leaks out, getting re-amplified; Phase cancellation

Directional Microphone Technology

Allows listener to hear sounds from the front and reduces output of sound coming from the back and sides of the listener; Automatic: switches automatically b/w omni-directional and directional depending on the listening environment; Adaptive: while in directional mode, will “adapt” to changing environment

Data Logging

Log of hearing aid; Audiologist can look at the data log once client comes back for follow-up after the fitting

Trainable Hearing Aids

• Patient-controlled training

• Hearing aid self-training

  • HA will slowly increase its volume over the next four weeks

Linked Hearing Aids

• When adjusting one aid, it automatically transmits that adjustment to the other aid

• Radio frequency transmission/Bluetooth

• Adjust one, adjustment will be made to the other

Frequency Lowering

• Target client: 

  • Low to mid frequencies: mild to moderate

    • High frequencies: severe to profound

• Goal: to “transpose” the high frequency information into the low/mid frequencies

Wireless Connectivity

• Remote reception

  • Assistive listening devices (ALDs), Hearing Assistive Technology (HATS)

  • Connectivity to communication devices