Electrical Evoked Stapedial Reflex Thresholds (eSRT) can be a very useful objective measure for the upper stimulus levels during the programming of a cochlear implant (Brickley et al., 2005; Buckler et al., 2003). The measure is particular useful during the fitting of cochlear implants in pediatrics (Cowdrey & Dawson, 2003), but also during the fitting on adults in particular adults unable to provide reliable behavioral measures (Andrade KC et al., 2013, Wolfe & Kasulis, 2008).
When using the Titan to obtain the eSRT levels, the cochlear implant is used as the stimulus source, while the Titan is used for monitoring. Titan monitors if there is any change as a function of time when a stimulus is presented through the cochlear implant.
eSRT protocol setup
Enter Menu – Seup – Protocol Setup and create a protocol pressing New. Add the eSRT test as a protocol by selecting and pressing Add . Press Settings to modify the protocol created.
|Set the probe tone frequency to 226 Hz, 678 Hz, 800 Hz, 1000 Hz.|
|Check the box to obtain an eSRT at the ambient pressure. If unchecked, the pressure will be obtained at peak pressure, if a peak pressure is present.|
|The more smoothing that is applied, the less noisy/detailed the trace will be. The smoothing level can be set from 0-4, with 0 being no smoothing applied and 4 being maximum smoothing applied.|
|Set the display of the reflexes to positive to have a positive deflection and negative to have a negative deflection of the reflexes.|
|This setting adds a threshold line to the graph, so it is possible to see when a threshold is present, e.g. by setting it for 0.05 ml.|
Once the protocol is modified, press OK to save the changes to the protocol.
eSRT Test Screen
Select an eSRT protocol.
226Hz, 678 Hz, 800 Hz, 1000 Hz.
Indicates probe status (in ear, out of ear, leaking, blocked).
Indicates how far the pressure is from target pressure.
|5||Tests in protocol||
Lists the tests that is part of the protocol, a checkmark at the right indicates the test is included, a checkmark at the left indicates data is obtained for the test.
Start and stop the measurement. In case of drifting, Stop and Start the measure to reset the baseline.
The time scale is continuous. Use the slider to move back and forth on the time scale.
Press the end of the time scale to go back to the point in time of the running measurement.
The dashed line indicates the setting of the reflex threshold level, which is used to see when a reflex is present.
Use the marker (M) to indicate when a reflex is present. This is done by clicking with the mouse in top of the reflex. As default the marker will indicate Mnumber (time).
Edit the name of the marker to help you identify which electrode it is from.
|12||Save and review session||
Press Save or Save & Exit to save the session. Review a saved session from the session list.
Brickley, G., Boyd, P., Wyllie, F., O’Driscoll, M., Webster, D., & Nopp, P. (2005). Investigations into electrically evoked stapedius reflex measures and subjective loudness percepts in the MED-EL COMBI 40+ cochlear implant. Cochlear Implants International, 6(1), 31-42.
Buckler L., Dawson K, Overstreet E. (2003) Relationship between Electrical Stapedial Reflex Thresholds and HiRes Program Settings.
Wolfe J., Schafer EC. (2015) Programming Cochlear Implants, Plural Publishing Inc. 2nd Edition
Wolfe J., Kasulis H. (2008) Relationships among objective measures and speech perception in adult users of the HiResolution Bionic Ear. Cochlear Implants Int. 9(2), 70-81.
Andrade KC., Leal MC., Muniz LF., Menezes PL., Albuquerque KM., Carnaúba AT. (2013). The importance of electrically evoked stapedial reflex in cochlear implant. Braz J Otorhinolaryngol. 80(1):68-77.
Julie Kosaner, Ilona Anderson, Zerrin Turan, Martina Deible (2009), Use of ESRT in Fitting Children with Cochlear Implants, Int. Adv. Otol. 2009; 5:(1) 70-79.