A meta-analysis to compare speech recognition in noise with bilateral cochlear implants and bimodal stimulation.

OBJECTIVE

This investigation quantified the relative benefits of binaural CI arrangements (i.e., bilateral, bimodal) for three binaural phenomena (i.e., binaural squelch, binaural summation, head-shadow effect) and sensitivity of two speech-recognition test paradigms (i.e., adaptive and fixed).

DESIGN

A repeated-measures meta-analytical approach was used to compare effect sizes between binaural CI arrangements for each of the three binaural-listening phenomena and between the two test paradigms.

STUDY SAMPLE

A total of 95 effect sizes were calculated and analyzed from 42 peer-reviewed studies published between January 2000 and April 2011.

RESULTS

Findings revealed significant effect sizes for both CI arrangements for the binaural phenomena of summation and head-shadow effect. A significant effect size for binaural squelch was determined only for bilateral CI users. Further, the two paradigms resulted in similar effect sizes for bilateral and bimodal users, with the exception of binaural squelch. Here, significant effect sizes were significant only in the fixed-testing paradigm.

CONCLUSIONS

The average user of binaural CI arrangements realizes the binaural phenomena of summation and the head-shadow effect, but only the bilateral CI arrangement is afforded the advantage of binaural squelch. Statistically, listeners fit with bilateral CIs have a slight advantage in binaural performance over those using bimodal stimulation.