In Brief:
The impact of bilateral cochlear implant use on speech perception in noise in 21 bilateral users of the MED-EL COMBI 40/40+ cochlear implants. Speech reception thresholds were measured using the Oldenburg sentence test. Speech was presented from the front. Noise was either presented from the front, or from the left side, or from the right side. Each condition was measured for unilateral and bilateral implant use. The 18 subjects from which a complete data set could be obtained showed a significant head shadow effect and summation effect for all test conditions whereas the squelch effect was significant for noise from the left side only. Average effect sizes were significant for all effects and amounted to 6.8 dB for the head shadow effect, 0.9 dB for the squelch effect, and 2.1 dB for the summation effect. Bilateral CI users can at least qualitatively benefit from the effects which are known from ‘normal hearing’ subjects, i.e., head shadow, summation, and squelch effect.
