The GSI Novus™ is a handheld, comprehensive newborn hearing screening instrument. The Novus features a touch screen display and user-friendly software in a compact hardware design. Novus may be configured with AABR, OAE, or both which allows for seamless two stage infant screening. When the Novus was initially released, there was only one protocol option each for AABR, DPOAE, and TEOAE. With the latest update to HearSIM, support for multiple protocols for all test modalities is included. The original protocols will be the default protocols that will come loaded on the device from the factory.
Summary of Default Protocols
The AABR protocol utilizes a fast rate auditory brainstem response (ABR) algorithm with a rate of 88/sec left ear and 92.5/sec right ear. The varying rates allow for simultaneous ear testing, which reduces overall test time, with the maximum being three minutes. Once the passing criteria has been met, the device will abort testing, and a passing result is usually achieved within 30 seconds. The stimulus is CE-Chirp® at 35 dB nHL and the device will provide a Pass, Fail, or Incomplete result. This protocol has been optimized for the infant ear and should only be utilized on infants under six months of age.
With DPOAE, L1/L2 are established at 65/55 dB SPL with the F2/F1 ratio equal to 1.22. Test frequencies include 5000, 4000, 3000, and 2000 Hz. To achieve a pass, 3/4 tested frequencies must record a SNR of 6 dB with a minimum amplitude of -5 dB. As with AABR, the device will abort testing once the passing criteria has been met. The maximum testing time for DPOAE is one minute and this protocol is appropriate for any age.
During TEOAE, an 83 dB click stimulus is analyzed in different frequency bands that center around 1400, 2000, 2800, and 4000 Hz. Similar to DPOAE, 3/4 frequencies with a SNR of at least 4 dB and minimum amplitude of -5 dB are needed for a passing result. While this protocol is appropriate for any age, it has been optimized for the infant ear. Maximum testing time is 60 seconds.
Both OAE protocols give only a Pass, Fail, or Incomplete result.
Newly Added Protocols for All Modalities
Newly added protocols for AABR include the CE-Chirp stimulus at varying intensities. The default will remain at 35 dB nHL, but now 30, 40, and 45 dB nHL are also available. In addition, a traditional Click Stimulus at 30, 35, 40, and 45 dB nHL can be selected. No other options will be available to change, and the device will still only function as a screening device, providing only a Pass, Fail, or Incomplete result.
For DPOAE, the default will be 2000 - 5000 Hz range, with three additional protocols added. 1.5 - 4k Hz will have the same passing criteria as the default protocol, and will include F2 frequencies of 4000, 3000, 2000, and 1500 k Hz. A 1.5 - 6k Hz protocol will consider five F2 frequencies (6000, 4000, 3000, 2000, 1500 Hz) with 3/5 needed for a pass, along with a minimum of 6 dB SNR and -5 dB amplitude. A 6-frequency protocol was also added between 1.5 - 5k Hz (6000, 4000, 3000, 2000, 1500 Hz) and will require 3/6 for a pass along with a 7 dB SNR and -5 minimum amplitude.
There are two new TEOAE protocols that both consider the same four center frequencies of 1400, 2000, 2800, and 4000 Hz with a click (non-linear) stimulus. The first variation measures at 83 dB peSPL and requires 2/4 passing criteria for each frequency band with a 6 dB minimum SNR and 0 dB SPL amplitude. The second measures at 80 dB peSPL and 3/4 passing frequencies with a minimum of 4 dB SNR and -5 dB amplitude. Both will have a maximum test time of one minute.
New protocols can be loaded onto the Novus with the companion HearSIM software with software version 2.1 and above.
Learn more by viewing our tutorial video: https://www.youtube.com/watch?v=kt-fD7lG0y4&list=PLf-QVux8dOsBPP-8NGoZ8YRQZbe_1TI6E&index=15