The audiologist obtained rarefaction and condensation click runs to evaluate CNS function and to rule out auditory neuropathy. The summation run is on the top, the rarefaction & condensation run polarity is noted on the printout. (You will need to click on the ABR to see the right ear responses.)
Pediatric patients have prolonged latencies relative to adults, but the same general guidelines about the interaural latency differences remains.
The audiologists at Pediatrix Inova Hospital of Fairfax County, VA took the data from the appendix of Jay Hall’s ABR text and formatted it into an Excel spreadsheet. The columns show the normal latency, and what value is prolonged by one and two standard deviations. With their permission, that format reference is attached. Below is an abstract of the data for age 4 years. As an example of how to read this information, wave I should come in at 1.72 ms but would not be abnormally prolonged unless the latency is 2.20 ms. The left ear latency is 2.10, so that is within normal limits.
I III V
Avg 1 SD 2 SD Avg 1 SD 2 SD Avg 1 SD 2 SD
1.72 1.96 2.20 3.99 4.24 4.49 5.90 6.14 6.38
I-III III-V I-V
Avg 1 SD 2 SD Avg 1 SD 2 SD Avg 1 SD 2 SD
2.21 2.47 2.73 1.89 2.12 2.35 4.19 4.46 4.73
- – Are the above traces normal?