A comparison of the Arizona Biomedical Institute (AzBio) and City University of New York (CUNY) sentence recognition tests: A study on English speaking postlingually deafened cochlear implant recipients in Australia

Background: The benefit of a cochlear implant device is measured by utilizing a number of speech tests, e.g. using words and sentences. Studies have shown that speech perception scores measured by the CUNY sentence test suffer from ceiling effects as early as three months after implantation. This has made longitudinal studies on speech perception performance of the cochlear implant (CI) recipients and comparison of different electrodes, coding strategies, manufacturer’s devices, etc. challenging. It has been shown that the AzBio is a more sophisticated test to evaluate the candidacy and postoperative performance in this population; however, the AzBio sentence test has not been tested in an Australian population. The primary aim of this study was to compare the AzBio and CUNY sentence tests in postlingually deafened adult CI recipients who speak Australian English as their first language to determine if the AzBio test has fewer ceiling effects.

Method: The study was conducted in two phases. Phase 1: twenty five adult participants, aged between 18-40 years (M=30.9; SD=6.2), who speak Australian English as their first language. All participants had normal hearing sensitivity. Phase 2: sixteen post-lingually deafened adult cochlear implant recipients, age 18-65 years (M=48.8; SD = 14.7). Speech perception of the participants was tested at three and six months post implantation with CUNY and AzBio sentence tests. Two random selections from the 15 AzBio words lists were used for the participants. Scores between 95-100% were considered to be ceiling scores.

Results: Phase 1: The intelligibility for AzBio sentence test across the 15 lists for the normal hearing participants ranged from 97-100% (Mean=99.5; SD=0.3). The average testing time for the normal hearing participants was 2.3 minutes (SD=0.17). Phase 2: Intelligibility at 3 months post implantation across the 15 lists for AzBio ranged from 30 to 94% (M=73; SD=16.4) and for the CUNY test ranged from 72 to 100% (M=93; SD=9.7). At 6 months post implantation CI participants’ sentence intelligibility ranged from 29 to 87% (M=63.3; SD=18.1) for AzBio and CUNY scores ranged from 71 to 100% (M=93.5; SD=9). At 3 months post implantation 50.8% of the participants scored above 95% in CUNY sentence test, increasing to 57.8% at 6 months and 71.9 at 12 months post-implantation. No ceiling effects were found for the AzBio test at either 3, 6 or 12 months post implantation. Mean testing times for the AzBio were 2.96 (SD: 0.8, range 2.24 to 5.29), 2.73 (SD: 0.5, range 2.23 to 4.8) and 2.63 (SD: 0.4, range 2.23 to 3.39) minutes for the tests conducted 3, 6 and 12 month post implantation respectively.

Conclusion: This study has shown that AzBio test is a reliable test to be used on post-lingually deafened cochlear implant recipients. Furthermore, fewer ceiling effects mean that the AzBio is a test that can be utilised for long term follow-ups and comparison between conditions. The test times are reasonable for incorporation into a clinical test battery. Further study is required to develop a normative data set for different age groups in Australian English speaking population.