5 Diagnostic Aud II ABR Presentation

Question 1

What are typical recording parameters for ABR testing using clicks?

Answer 1

• Low pass filter: between 2kHz & 3kHz
• High pass filter: between 5Hz & 30Hz
• Click polarity could be rarefaction, condensation, or alternating.
• Most common electrode arrangement: Vertex active referenced to ipsilateral earlobe or mastoid.
• Typically averaged over 2000 trials
• Possible to record both ipsi & contra response simultaneously.

Question 2

Typical click rate for adults & why?

Answer 2

Wave I: Use a slower CR (5/s or 11/s) and Wave I will get larger.
Wave 5: Use a faster CR. This will decrease the other waves but keep Wave 5 robust…easier to identify it.

Question 3

What are some possible strategies for identifying Waves I & V of the ABR?

Answer 3

• Knowing that wave I is the first positive peak following the baseline recording and that wave V is the largest positive peak prior to negative-going baseline crossing
• Changing the electrode montage. *Closer to TM for wave I and on neck for wave V.
• Changing the stimulus rate
• Changing the stimulus intensity
• Changing stimulus polarity

Question 4

Why is it useful to plot ABR latency-intensity function for individuals with hearing loss?

Answer 4

The latency intensity function can help predict the type of hearing loss an individual as.

Question 5

How are subject factors related to the amplitude and latency of the ABR components?

Answer 5

• Waveform amplitude is largest and latencies are shorter in females relative to males
• ABR waveforms are smaller in amplitude and longer latencies in infants than in adults and both variables change as a function of gestational age
• Latencies are longer and ABR responses are more variable with advanced age