AudiologyOnline Phone: 800-753-2160
Otometrics Madsen, Aurical, Bio-logic - April 2019

When Do You Use Masking for ABR?

Karen Morris, MS, CCC-A

June 21, 2010

Share:

Question

Are there any rules when you should use masking when testing ABR, and how do you know how much masking to use? How does the masking noise affect the result?

Answer

The easiest way to determine when to mask during ABR testing, is to examine the collected ABR. For air conduction, if the absolute latencies of waves I and V are normal, there is no need to mask. This is because the crossover of the stimulus to the non-test ear takes time. This time delay would in turn delay the absolute latencies of the waveforms. The latencies would also be delayed due to the inter-aural attenuation (IA) of the stimulus. (The IA of the click is 65dB.) Therefore, a normal ABR can only be elicited from the stimulated ear. If, however, the latencies are abnormal, masking is needed.

For bone conduction, masking is not required if wave I is present at normal latencies. This is because wave I is a near-field potential and a normal wave I can only be recorded from the electrode near the stimulated ear. If, however, wave I is absent or delayed for bone conduction, masking is needed.

Most ABR systems offer white noise as a masker which is an appropriate choice because the click is a broadband stimulus. The amount of masking noise needed would be enough to elevate the hearing threshold in the non-test ear so cross over is prevented. For example, if a click is presented at 95 dB nHL via insert earphones and the IA is 65 dB, the signal will be reaching the non-test ear at 30 dB. Enough masking noise (without over-masking) that elevates the threshold in that ear above 30 dB would be adequate—approximately 40-50 dB. Masking noise does not affect the latency or amplitude of the response.

Karen Morris, M.S., CCC/A is the Manager of Audiology Services for GN Otometrics. She received her Master's degree in Audiology from Purdue University. She has worked as a clinical audiologist for over 20 years in a variety of settings and has extensive clinical experience that includes evoked potentials and vestibular assessment. Prior to joining GN Otometrics, Karen worked for Bio-logic for 7 years most recently as the Technical Support Manager and Sales Specialist.

For more information about GN Otometrics, visit http://www.otometrics.com/ or the GN Otometrics web channel on AudiologyOnline.


Karen Morris, MS, CCC-A

Manager of Audiology Services for GN Otometrics


Related Courses

A Guide to Bithermal Caloric Testing
Presented by Amanda Cerka Mroz, AuD, FAAA, CCC-A
Recorded Webinar
Otometrics North America, a division of Natus (formerly Audiology Systems)

Presenter

Amanda Cerka Mroz, AuD, FAAA, CCC-A
Course: #8151 Hour
  'Good explanations'   Read Reviews
No CEUs/Hours Offered
The purpose of this course is to provide an in-depth discussion of the caloric testing portion of the VNG/ENG test battery. Content will include descriptions of testing procedures, analysis and interpretation of results.

View this Course for FREE.
Need CEUs? Become a AudiologyOnline member to get unlimited CEUs.

Only $99/yr

Learn More

Evoked Potentials Part 3: Auditory Steady State Response
Presented by Wendy Crumley, MS, CCC-A
Recorded Webinar
Otometrics North America, a division of Natus (formerly Audiology Systems)

Presenter

Wendy Crumley, MS, CCC-A
Course: #8781 Hour
  'Instruction was easy to follow!'   Read Reviews
No CEUs/Hours Offered
This presentation presents tips and recommendations for collecting quality ASSR responses. It includes understanding ASSR, uncovering the myths about ASSR, patient preparation, data collection as well as understanding the ICS RapidASSR algorithm and determining the threshold response.

View this Course for FREE.
Need CEUs? Become a AudiologyOnline member to get unlimited CEUs.

Only $99/yr

Learn More

Best Practices in Electrophysiology
Presented by Wendy Crumley-Welsh, MS, CCC-A
Text/Transcript
Otometrics North America, a division of Natus (formerly Audiology Systems)

Presenter

Wendy Crumley-Welsh, MS, CCC-A
Course: #233505 Hours
  'Refresher with new detail'   Read Reviews
No CEUs/Hours Offered
This course is a compilation of two articles discussing best practices in electrophysiology. The first describe Auditory Brainstem Response testing, including test parameters, waveform identification and diagnostic techniques. Part 2 reviews electrocochleography, MLR, P300 and Cortical Response testing, including test techniques and diagnostic guidelines.

View this Course for FREE.
Need CEUs? Become a AudiologyOnline member to get unlimited CEUs.

Only $99/yr

Learn More

Vestibular Evoked Myogenic Potentials (VEMP) - How Do I Get Started?
Presented by Jill Craig
Recorded Webinar
Otometrics North America, a division of Natus (formerly Audiology Systems)

Presenter

Jill Craig
Course: #270421 Hour
  'Great slides and explanations'   Read Reviews
This course will provide the attendee with the fundamentals of the vestibular evoked myogenic potential (VEMP). It will include: • An overview of the vestibular system • How to collect the cervical VEMP (cVEMP) and ocular VEMP (oVEMP) • Common pitfalls in testing and contraindications • VEMP results and interpretation. NOTE: There were two times that the presenter lost audio for a few seconds, no information was lost.

View this Course for FREE.
Need CEUs? Become a AudiologyOnline member to get unlimited CEUs.

Only $99/yr

Learn More

Efficient Use of the ICS Chartr EP 200
Presented by Kathleen Hill, AuD, FAAA
Recorded Webinar
Otometrics North America, a division of Natus (formerly Audiology Systems)

Presenter

Kathleen Hill, AuD, FAAA
Course: #285791 Hour
  'very practical information presented clearly'   Read Reviews
The purpose of this course is to provide instruction for efficient use of the Chartr EP 200 ABR system.

View this Course for FREE.
Need CEUs? Become a AudiologyOnline member to get unlimited CEUs.

Only $99/yr

Learn More