SISI Test KA450

The SISI test (Short Increment Sensitivity Index) is used to differentiate between inner ear damage and neural hearing loss. It is usually sufficient to perform this test at one frequency. The SISI test is only relevant if the hearing loss at one frequency is at least 40 dB. It is carried out 20 dB above the determined hearing threshold.

To switch to SISI test mode, press the "SISI" button (27). The parameters of the SISI test are shown on the LC display (55) and the indicator (23) lights up.

Set the test side using button (6) and then select the corresponding frequency using buttons (52) or (53) based on the available audiogram. Now use the level control of the selected side (42) or (47) to set a volume 20 dB higher than the hearing threshold at the selected frequency.

You can now start the test by pressing the "OK" button (30). The patient now hears a volume increase of 5 dB (increment) approximately every 5 seconds. The patient's task is to press the patient hand control when they hear an increment. They must do this within 2 seconds of the increment.

For the examiner, the text "5 dB" (or 3, 2, 1, dB in the other test levels) is highlighted on the LC display when an increment is given. Furthermore, the number of increments given as well as the increments recognized by the patient and their percentage ratio are indicated.

A test run consists of 20 increments, but can also be aborted earlier by pressing the "OK" button (30) and restarted if required. The test parameters cannot be changed during a test run.

After the test run with 5 dB increments, the level increments can be reduced to 3dB, 2dB and finally to 1 dB by pressing the "SISI" button (27). The tests with 5, 3 & 2 dB increments are exercises, the actual diagnostics are carried out with 1 dB increments.

The test run with 1 dB increment used for diagnostics can be aborted if the respondent has not recognized any after 10 increments. In this case, the test is scored 0%.

The test can also be aborted if the respondent has recognized all of them after 10 increments. The test is then rated as 100% and thus provides an indication of inner ear damage.