Test Procedure - SISI (Short Increment Sensitivity Index) Test
The SISI test is used to detect small level changes in a steady-state signal in
patients with disorders of the cochlea. The SISI tests a patient’s ability to detect a
1 dB level change in a pure tone stimulus presented at 20 dB SL. A SISI consists
of 20 target increments (200 msec at 1, 2, or 5 dB) presented every 5 seconds and
can be completed for a number of frequencies. The SISI test is scored in terms of
the percentage of correctly identified 1 dB increments out of a possible 20.
Scores of higher than 70% indicate cochlear involvement equals Positive SISI.
Scores of less than 70% indicate auditory disorders not in the cochlea or normal
hearing equals Negative SISI.
Presentation Level
• Set the attenuator to 20 dB SL re: the pure tone threshold for the test
frequency.
Test Instructions
“You will hear a steady tone in your left or right ear. There may be an increase
in loudness. Each time you hear the increase in loudness, press the patient
response button.”
Test Procedure
• Familiarize patient by presenting an easily heard (5 dB) SISI step. To do
this, press the presentation bar one time per presentation of the SISI
increment.
• Select dB Step (1 dB) for the test.
• To begin, press the “Interrupt” button to automatically begin the
stimulus level increment change every 5 seconds.
• Observe the patient responses – Record them using the
“correct/incorrect” counter.
• Press Store to record the SISI score for each frequency. Results are
displayed on the results table.
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