Factors associated with broad binaural pitch fusion in children and adults with hearing aids and cochlear implants

Many hearing-impaired adults who use hearing aids (HAs) and/or cochlear implants (CIs) have broad binaural pitch fusion, such that sounds with large pitch differences are fused across ears (Reiss et al., JARO 2014; JASA). The goal was to determine which subject factors are associated with broad binaural pitch fusion. Binaural pitch fusion was measured in bilateral HA users, bimodal CI users who use a HA in the contralateral ear, and bilateral CI users. Fusion ranges were measured by simultaneous, dichotic presentation of reference and comparison stimuli in opposite ears, and varying the comparison stimulus to find the range that fused with the reference stimulus. Both children (ages 6-9) and adults were tested. Children in the HA and bilateral CI groups had broader fusion than the bimodal CI group. In addition, broad fusion was positively correlated with long durations of HA use and early onset of hearing loss in adult HA users, and negatively correlated with duration of CI use in pediatric bimodal CI use...