ASSR testing was conducted three weeks after the ABR testing.  The report notes that the parents think he can hear – he responds to things like a crinkling bag of chips and hears his father getting up in the morning.  The table above (click for full screen view) shows the intensities and frequencies tested. The numbers, which are largely illegible, are the probability values – telling us the probability that the results happened by chance. If the p values are low enough, we presume the results are truly present.  The color original is easier to read.  Here, the lighter shaded blocks are responses, dark colored blocks indicate that the results could be obtained by chance.

To the left of the 500 Hz responses are + and – symbols to aid in seeing how to read the table.  Note that for both ears, there are higher intensity test series with “no response” and then a positive response at lower levels, followed again by no response at yet lower levels. This is not an ideal pattern of data.  Ideally all suprathreshold responses would be present, and below a given level, all responses should be negative.  Myogenic activity can contaminate traces, causing negative findings when hearing is present. And, when doing testing at many frequencies, and many intensities, there is also the chance that one or more of the present responses is really not a true response.  If responses were absent at “suprathreshold” levels, then we need to consider that the myogenic noise could also cause the lower intensity runs to falsely show no response.

The results are summarized in a “physiologic audiogram”.

• Compare the ASSR results to the ABR results.