Clinical application of spectral modulation detection (Kessler et al., 2020)

Purpose: The purpose of this study was to investigate the relationship between speech recognition benefit derived from the addition of a hearing aid (HA) to the nonimplanted ear (i.e., bimodal benefit) and spectral modulation detection (SMD) performance in the nonimplanted ear in a large clinical sample. An additional purpose was to investigate the influence of low-frequency pure-tone average (PTA) of the nonimplanted ear and age at implantation on the variance in bimodal benefit.
Method: Participants included 311 unilateral cochlear implant (CI) users who wore an HA in the nonimplanted ear. Participants completed speech recognition testing in quiet and in noise with the CI-alone and in the bimodal condition (i.e., CI and contralateral HA) and SMD in the nonimplanted ear.
Results: SMD performance in the nonimplanted ear was significantly correlated with bimodal benefit in quiet and in noise. However, this relationship was much weaker than previous reports with smaller samples. SMD, low-frequency PTA of the nonimplanted ear from 125 to 750 Hz, and age at implantation together accounted for, at most, 19.1% of the variance in bimodal benefit.
Conclusions: Taken together, SMD, low-frequency PTA, and age at implantation account for the greatest amount of variance in bimodal benefit than each variable alone. A large portion of variance (~80%) in bimodal benefit is not explained by these variables.

Supplemental Material S1. Scatter plots displaying the following results:
A significant correlation was found between acoustic benefit for CNC words and LFPTA of the nonimplanted ear from 125 to 750 Hz (n = 305, r = .24, p < .0001), QSMD in nonimplanted ear (n = 255, r = .26, p < .0001), and age at implantation (n = 305, r = .14, p = .018). There was a significant correlation between acoustic benefit for AzBio at +5 dB SNR with LFPTA in the nonimplanted ear from 125 to 750 Hz (n = 162, r = .30, p = .0001), QSMD in the nonimplanted ear (n = 141, r = .20, p = .017), and age at implantation (n = 162, r = .20, p = .011).

Kessler, D. M., Wofle, J., Blanchard, M., & Gifford, R. H. (2020). Clinical application of spectral modulation detection: Speech recognition benefit for combining a cochlear implant and contralateral hearing aid. Journal of Speech, Language, and Hearing Research. Advance online publication. https://doi.org/10.1044/2020_JSLHR-19-00304